Introduction to Agriculture

Book · January 2011with 130,957 Reads
Publisher: 1st
Publisher: None
Publisher: Anonymous
Cite this publication
Introduction to Agriculture are basically notes for Fresh students who have just enrolled in any Agricultural University. These notes are series of lectures delivered by teachers of Agronomy of the University of Agriculture Peshawar Pakistan. These notes will also be helpful for those who are aspirant to pass CSS, FPSC or any other competitive exams about agriculture conducted in Pakistan.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Introduction to Agriculture Notes prepared by: Aqleem Abbas
The word agriculture is derived from the Latin word ager………….its mean soil and cultural means cultivation. Simply
we can say cultivation of soil
Technical definition
It is the science in art of farming including the work of cultivating the soil, producing the crops and raising livestock.
It has two main branches 1. Crops 2. Animals
1. Forestry
2. Crops
1. Fisheries
2. Livestock
Components of agriculture
It has four components
1. Crops 54 %
2. Livestock 41 %
3. Fisheries 4.5 %
4. Forestry .5 %
1. Supply or provide us food and fiber
2. Contributes about 25 % in GDP
3. Agriculture provides raw materials to industries.
4. Agriculture provides 80 % in foreign exchange.
5. 45 % labor force in Pakistan are engaged in agriculture
6. It is backbone of our country.
It is derived from Greek word agro—field Nomo’s –manage—so development and management of
crop and soil sciences to produce abundant high quality food and fibers in a protected
environment. Students who study agronomy are called agronomist.
Causes of low yield in Pakistan
Maize is 70 % less than America and Canada.
Our yield is low because low soil fertility. Our soil is 60 percent deficient in nutrients.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Low yielding varieties.
Poor agronomic practices
Farmers are illiterate
Application of water, harvesting of crops, attacks of insects, diseases, weeds
Non availability of seed.
Non availability of chemicals
Un availability of inputs
Low income
Water logging, salinity
Small land holdings
Lack of agro based industry.
Lack of storage, transport facilities and next one is weak govt policy.
Natural disaster, drought and
In case of KPK rains has not occurred in time
1. Use of high yielding variety
2. Proper tillage practices
3. Prepare seed bed properly
4. Balance fertilizers
5. Proper irrigation
6. Control of pest and diseases, weeds.
7. Proper time sowing
8. Time of harvesting.
9. Proper seed rate
10. Crop rotation-growing of crops one after the other in regular sequence in order to keep in view that fertility of
soil may not disturb.
11. Multiple cropping system
Our lands are so small because of small holdings and because of population we in Pakistan grow more crops in one year.
America grow only one crop in a year called mono cropping
Modern agriculture depends heavily on engineering and technology and on the biological and physical sciences. Irrigation,
drainage, conservation, and sanitary engineering—each of which is important in successful farming—are some of the fields
requiring the specialized knowledge of agricultural engineers. Agricultural chemistry deals with other vital farming concerns,
such as the application of fertilizer, insecticides (see Pest Control), and fungicides, soil makeup, analysis of agricultural
products, and nutritional needs of farm animals. Plant breeding and genetics contribute immeasurably to farm
productivity. Genetics has also made a science of livestock breeding. Hydroponics, a method of soilless gardening in which
plants are grown in chemical nutrient solutions, may help meet the need for greater food production as the world’s
population increases. The packing, processing, and marketing of agricultural products are closely related activities also
influenced by science. Methods of quick-freezing and dehydration have increased the markets for farm products.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Mechanization, the outstanding characteristic of late 19th- and 20th-century agriculture, has eased much of the backbreaking
toil(involving enormous physical effort) of the farmer. More significantly, mechanization has enormously increased farm
efficiency (desired result without using much effort) and productivity (rate of production). Animals including horses, oxen,
llamas, alpacas, and dogs, however, are still used to cultivate fields, harvest crops, and transport farm products to markets in
many parts of the world. Airplanes and helicopters are employed in agriculture for seeding, spraying operations for insect and
disease control, transporting perishable products, and fighting forest fires. Increasingly satellites are being used to monitor
crop yields. Radio and television disseminate vital weather reports and other information such as market reports that
concern farmers. Computers have become an essential tool for farm management.
Over the 10,000 years since agriculture began to be developed, peoples everywhere have discovered the food value of wild
plants and animals, and domesticated and bred them. The most important crops are cereals such as wheat, rice, barley, corn,
and rye; sugarcane and sugar beets; meat animals such as sheep, cattle, goats, and pigs or swine; poultry such as chickens,
ducks, and turkeys; animal products such as milk, cheese, and eggs; and nuts and oils. Fruits, vegetables, and olives are also
major foods for people. Feed grains for animals include soybeans, field corn, and sorghum. Agricultural income is also derived
from nonfood crops such as rubber, fiber plants, tobacco, and oil seeds used in synthetic chemical compounds, as well as
animals raised for pelts(animal skin). Conditions that determine what is raised in an area include climate, water supply and
waterworks, terrain, and ecology. In 2003, 44 percent of the world’s labor force was employed in agriculture. The
distribution ranged from 66 percent of the economically active population in sub-Saharan Africa (mali,Ethiopia,Zimbabwe
etc) to less than 3 percent in the United States and Canada. In Asia and the Pacific the figure was 60 percent; in Latin
America and the Caribbean, 19 percent; and in Europe, 9 percent. Farm size varies widely from region to region. In the early
2000s the average for Canadian farms was about 273 hectares (about 675 acres) per farm; for farms in the United States,
180 hectares (440 acres). By contrast, the average size of a single land holding in India was 2 hectares (about 5 acres).
Size also depends on the purpose of the farm. Commercial farming, or production for cash, usually takes place on large
holdings. The latifundia of Latin America are large, privately owned estates worked by tenant labor. Single-crop
plantations produce tea, rubber, and cocoa. Wheat farms are most efficient when they comprise thousands of hectares
and can be worked by teams of people and machines. Australian sheep stations and other livestock farms must be large to
provide grazing for thousands of animals. Individual subsistence(condition of managing to stay alive) farms or small-
family mixed-farm operations are decreasing in number in developed countries but are still numerous in the developing
countries of Africa and Asia. Nomadic herders range over large areas in sub-Saharan Africa, Afghanistan, and Lapland
(region largely within the arctic circle, extending across the northern parts of Norway,Sweden, finland and the Kola
peninsula of Russia.) ; and herding is a major part of agriculture in such areas as Mongolia.
Much of the foreign exchange earned by a country may be derived from a single agricultural commodity; for example, Sri
Lanka depends on tea, Denmark specializes in dairy products, Australia in wool, and New Zealand and Argentina in meat
products. In the United States, wheat, corn, and soybeans have become major foreign exchange commodities in recent
Introduction to Agriculture Notes prepared by: Aqleem Abbas
The importance of an individual country as an exporter of agricultural products depends on many variables. Among them is
the possibility that the country is too little developed industrially to produce manufactured goods in sufficient quantity or
technical sophistication (advance technical development). Such agricultural exporters include Ghana, with cocoa, and
Myanmar (formerly Burma), with rice. However, a developed country may produce surpluses that are not needed by its
own population; this is the case with the United States, Canada, and some other countries. Because nations depend on
agriculture not only for food but for national income and raw materials for industry as well, trade in agriculture is a constant
international concern. It is regulated by the World Trade Organization. The Food and Agriculture Organization of the United
Nations (FAO) (to eliminate hunger on world scale main headquarter is Rome, Italy) directs much attention to agricultural trade
and policies. According to the FAO, world agricultural production, stimulated by improving technology, grew steadily from the
1960s to the 1990s. Per capita food production saw sustained growth in Latin America, the Caribbean, Asia, and the Pacific areas
(surrounding pacific ocean), and limited growth in the Near East ( middle east) and North Africa. The only region not to
experience growth during the 1980s and 1990s was sub-Saharan Africa, which suffered from climatic conditions that
made agriculture difficult. Although agricultural growth began to taper off in the year 2000, it continued to outpace world
population growth.
The history of agriculture may be divided into five broad periods of unequal length, differing widely in date according to
1. Prehistoric,
2. Historic through the Roman period,
3. Feudal,
4. Scientific
5. Industrial.
A countertrend to industrial agriculture, known as sustainable (exploiting natural resources without destroying ecological
balance of an area), agriculture or organic farming, may represent yet another period in agricultural history.
Early farmers were, archaeologists agree, largely of Neolithic culture (latest period of stone age, between about 8000BC and
5000 BC,characterized by the development of settled agriculture and use of polished stone tools and weapon) Sites
occupied by such people are located in southwestern Asia in what are now Iran, Iraq, Israel, Jordan, Syria, and Turkey ; in
southeastern Asia, in what is now Thailand; in Africa, along the Nile River in Egypt; and in Europe, along the Danube
River and in Macedonia, Thrace, and Thessaly (historic regions of southeastern Europe). Early centers of agriculture have
also been identified in the Huang He (Yellow River) area of China; the Indus River valley of India and Pakistan; and the
Tehuacán Valley of Mexico, northwest of the Isthmus of Tehuantepec. The dates of domesticated plants and animals vary
with the regions, but most predate the 6th millennium
, and the earliest may date from 10,000
. Scientists have carried
out carbon-14 testing of animal and plant remains and have dated finds of domesticated sheep at 9000
in northern
Iraq; cattle in the 6th millennium
in northeastern Iran; goats at 8000
in central Iran; pigs at 8000
in Thailand
and 7000
in Thessaly; onagers, or asses, at 7000
in Iraq; and horses around 4000
in central Asia. The llama and
alpaca were domesticated in the Andean regions of South America by the middle of the 3rd millennium
Introduction to Agriculture Notes prepared by: Aqleem Abbas
According to carbon dating, wheat and barley were domesticated in the Middle East in the 8th millennium
; millet and
rice in China and Southeast Asia by 5500
; and squash in Mexico about 8000
. Legumes found in Thessaly and
Macedonia are dated as early as 6000
. Flax was grown and apparently woven into textiles early in the Neolithic Period.
The transition from hunting and food gathering to dependence on food production was gradual, and in a few isolated parts of the
world this transition has not yet been accomplished. Crops and domestic meat supplies were augmented by fish and wildfowl
as well as by the meat of wild animals. The farmer began, most probably, by noting which of the wild plants were edible or
otherwise useful and learned to save the seed and to replant it in cleared land. Lengthy cultivation of the most prolific and
hardiest plants yielded stable strains. Herds of goats and sheep were assembled from captured young wild animals, and
those with the most useful traits—such as small horns and high milk production—were bred. The wild aurochs was the
ancestor of European cattle, and an Asian wild ox of the zebu, was the ancestor of the humped cattle of Asia. Cats, dogs,
and chickens were also domesticated very early.
Neolithic farmers lived in simple dwellings—caves and small houses of sun baked mud brick or reed and wood. These homes
were grouped into small villages or existed as single farmsteads surrounded by fields, sheltering animals and humans in
adjacent or joined buildings. In the Neolithic Period, the growth of cities such as Jericho (founded about 9000
) was
stimulated by the production of surplus crops.
Pastoralism (individual country living) may have been a later development. Evidence indicates that mixed farming, combining
cultivation of crops and stock rising, was the most common Neolithic pattern. Nomadic herders, however, roamed (wander
aimlessly) the steppes (tree less plains covered by grasses} of Europe and Asia, where the horse and camel were domesticated.
The earliest tools of the farmer were made of wood and stone. They included the stone adz, an ax like tool with blades at right
angles to the handle, used for woodworking; the sickle or reaping knife with sharpened stone blades, used to gather grain; the
digging stick, used to plant seeds and, with later adaptations, as a spade or hoe; and a rudimentary plow, a modified tree
branch used to scratch the surface of the soil and prepare it for planting. The plow was later adapted for pulling by oxen.
The hilly areas of southwestern Asia and the forests of Europe had enough rain to sustain agriculture, but Egypt
depended on the annual floods of the Nile River to replenish soil moisture and fertility. The inhabitants of the Fertile
Crescent around the Tigris and Euphrates rivers in the Middle East also depended on annual floods to supply irrigation
water. Drainage was necessary to prevent the erosion of land from the hillsides through which the rivers flowed. The farmers
who lived in the area near the Huang He developed a system of irrigation and drainage to control the damage caused to
their fields in the flood plain of the meandering river.
Although Neolithic settlements were more permanent than the camps of hunting peoples, villages had to be moved
periodically in some areas when the fields lost their fertility from continuous cropping. This was most necessary in northern
Europe, where fields were produced by the slash-and-burn method of clearing. Settlements along the Nile River, however, were
more permanent, because the river deposited fertile silt annually.
With the close of the Neolithic period and the introduction of metals, the age of innovation in agriculture was largely over.
The historical period—known through written and pictured materials, including the Bible; Middle Eastern records and
Introduction to Agriculture Notes prepared by: Aqleem Abbas
monuments; and Chinese, Greek, and Roman writings—was highlighted by agricultural improvements. A few high points must
serve to outline the development of worldwide agriculture in this era, roughly defined as 2500
500. For a similar period
of development in Central and South America, somewhat later in date Some plants became newly prominent. Grapes and wine
were mentioned in Egyptian records about 2900
, and trade in olive oil and wine was widespread in the Mediterranean
area by the 1st millennium
. Rye and oats were cultivated in northern Europe about 1000
Many vegetables and fruits, including onions, melons, and cucumbers, were grown by the 3rd millennium
in Ur (now
Iraq). Dates and figs were an important source of sugar in the Middle East, and apples, pomegranates, peaches, and
mulberries were grown in the Mediterranean area. Cotton was grown and spun in India about 2000
, and linen and silk
were used extensively in 2nd-millennium
China. Felt was made from the wool of sheep in Central Asia and the Russian
steppes. The horse, introduced to Egypt about 1600
, was already domesticated in Mesopotamia and Asia Minor. The
ox-drawn four-wheeled cart for farm work and two-wheeled chariots drawn by horses were familiar in northern India in
the 2nd millennium
. Improvements in tools and implements were particularly important. Tools of bronze and iron were
longer lasting and more efficient, and cultivation was greatly improved by such aids as the ox-drawn plow fitted with an
iron-tipped point, noted in the 10th century
in Palestine. In Mesopotamia in the 3rd millennium
a funnel-like device
was attached to the plow to aid in seeding, and other early forms of seed drills were used in China. Farmers in China further
improved efficiency with the invention of a cast-iron moldbar plow. Threshing was also done with animal power in Palestine
and Mesopotamia, although reaping, binding, and winnowing were still done by hand. Egypt retained hand seeding through this
period on individual farm plots and large estates alike. Storage methods for oil and grain were improved. Granaries—jars, dry
cisterns, silos, and bins containing stored grain—provided food for city populations. Without adequate food supplies and
trade in both food and nonfood items, the high civilizations of Mesopotamia, northern India, Egypt, Greece, and Rome
would not have been possible. Irrigation systems in China, Egypt, and the Middle East were refined and expanded,
putting more land into cultivation. The forced labor of peasants and the growth of bureaucracies to plan and supervise
work on irrigation systems were probably basic in the development of the city-states of Sumer (now Iraq and Kuwait).
Windmills and water mills, developed toward the end of the Roman period, increased control over the many uncertainties of
weather. The introduction of fertilizer, mostly animal manures, and the rotation of fallow and crop land increased crop
production.NMixed farming and stock raising, which were flourishing in the British Isles and on the continent of Europe as far
north as Scandinavia at the beginning of the historical period, already displayed a pattern that persisted throughout the next 3,000
years. In many regions, fishing and hunting supplemented the food grown by farmers.About
100 Roman historian Cornelius
Tacitus described the Germans as a tribal society of free peasant warriors who cultivated their own lands or left them to
fight. About 500 years later, a characteristic European village had a cluster of houses in the middle, surrounded by rudely
cultivated fields comprising individually owned farmlands; and meadows, woods, and wasteland were used by the entire
community. Oxen and plow were passed from one field to another, and harvesting was a cooperative effort.
The Roman Empire appears to have started as a rural agricultural society of independent farmers. In the 1st millennium
after the city of Rome was established, however, agriculture started a development that reached a peak in the Christian
era. Large estates (sector of society with some political power} that supplied grain to the cities of the empire were owned by
absentee landowners and cultivated by slave labor under the supervision of hired overseers. As slaves, usually war captives,
decreased in number, tenants replaced them. The late Roman villa of the Christian era approached the medieval ( old fashion or
middle age in Europe) manor (noble house and land) in organization; slaves and dependent tenants were forced to work on a
fixed schedule, and tenants paid a predetermined share to the estate owner. By the 4th century
, serfdom was well established,
and the former tenant was attached to the land.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
The feudal period in Europe began soon after the fall of the Roman Empire, reaching its height about
1100. This period was
also marked by development of the Byzantine Empire (late roman empire with its capital constanipole) and the power of the
Saracens (Muslim opposing Christian crusade) in the Middle East and southern Europe. Agriculture in Spain, Italy, and
southern France, in particular, was affected by events outside continental Europe.
As the Arab influence extended to Egypt and later Spain, irrigation was extended to previously sterile or unproductive
land. In Egypt, grain production was sufficient to allow the country to sell wheat in international markets. In Spain, vineyards
were planted on sloping land, and irrigation water was brought from the mountains to the plains. In some areas of the
Middle East, oranges, lemons, peaches, and apricots were cultivated.
Rice, sugarcane, cotton, and vegetables such as spinach and artichokes, as well as the characteristic Spanish flavoring saffron,
were produced. The silkworm was raised and its food, the mulberry tree, was grown.
By the 12th century agriculture in the Middle East had become static, and Mesopotamia declined to subsistence
production levels when irrigation systems were destroyed by invading Mongols. The Crusades, however, increased
European contact with Islamic lands and familiarized western Europe with citrus fruits and silk and cotton textiles.
The structure of agriculture was not uniform. In Scandinavia (Norway Sweden and Denmark) and eastern Germany, the small
farms and villages of previous years remained. In mountainous areas and in the marshlands of Slavic (Bulgaria, Russia and
polish) Europe, the manorial system could not flourish.
A manor required roughly 350 to 800 hectares (about 900 to 2,000 acres) of arable land and the same amount of other prescribed
lands, such as wetlands, wood lots, and pasture. Typically, the manor was a self-contained community. On it was the large home
of the holder of the fief—a military or church vassal of rank, sometimes given the title lord—or of his steward. A parish church
was frequently included, and the manor might make up the entire parish. One or more villages might be located on the manor,
and village peasants were the actual farmers. Under the direction of an overseer, they produced the crops, raised the meat and
draft animals, and paid taxes in services, either forced labor on the lord’s lands and other properties or in forced military service.
A large manor had a mill for grinding grain, an oven for baking bread, fishponds, orchards, perhaps a winepress or oil press, and
herb and vegetable gardens. Bees were kept to produce honey.
Woolen garments were produced from sheep raised on the manor. The wool was spun into yarn, woven into cloth, and then sewn
into clothing. Linen textiles could also be produced from flax, which was grown for its oil and fiber.
The food served in a feudal castle or manor house varied according to the season and the lord’s hunting prowess. Hunting for
meat was, indeed, the major nonmilitary work of the lord and his military retainers. The castle residents could also eat domestic
ducks, pheasants, pigeons, geese, hens, and partridges; fish, pork, beef, and mutton; and cabbages, turnips, carrots, onions, beans,
and peas. Bread, cheese and butter, ale and wine, and apples and pears also appeared on the table. In southern Europe olives and
olive oil might be used, often instead of butter.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Leather was produced from the manor’s cattle. Horses and oxen were the beasts of burden; as heavier horses were bred and a new
kind of harness was developed, they became more important. A blacksmith, wheelwright, and carpenter made and maintained
crude agricultural tools.
The cultivation regime was rigidly prescribed. The arable land was divided into three fields: one sown in the autumn in wheat or
rye; a second sown in the spring in barley, rye, oats, beans, or peas; and the third left fallow. The fields were laid out in strips
distributed over the three fields, and without hedges or fences to separate one strip from another. Each male peasant head of
household was allotted about 30 strips. Helped by his family and a yoke of oxen, he worked under the direction of the lord’s
officials. When he worked on his own fields, if he had any, he followed village custom that was probably as rigid as the rule of an
About the 8th century a four-year cycle of rotation of fallow appeared. The annual plowing routine on 400 hectares would be 100
hectares plowed in the autumn and 100 in the spring, and 200 hectares of fallow plowed in June. These three periods of plowing,
over the year, could produce two crops on 200 hectares, depending on the weather. Typically, ten or more oxen were hitched to
the tongue of the plow, often little more than a forked tree trunk. The oxen were no larger than modern heifers. At harvest time,
all the peasants, including women and children, were expected to work in the fields. After the harvest, the community’s animals
were let loose on the fields to forage.
Some manors used a strip system. Each strip, with an area of roughly 0.4 hectare (about 1 acre), measured about 200 m (about
220 yd) in length and from 1.2 to 5 m (4 to 16.5 ft) in width. The lord’s strips were similar to those of the peasants distributed
throughout good and bad field areas. The parish priest might have lands separate from the community fields or strips that he
worked himself or that were worked by the peasants.
In all systems, the lord’s fields and needs came first, but about three days a week might be left for work on the family strips and
garden plots. Wood and peat for fuel were gathered from the commonly held wood lots, and animals were pastured on village
meadows. When surpluses of grain, hides, and wool were produced, they were sent to market.
In about 1300 a tendency developed to enclose the common lands and to raise sheep for their wool alone. The rise of the textile
industry made sheep raising more profitable in England, Flanders (now in Belgium), Champagne (France), Tuscany and
Lombardy (Italy), and the Augsburg region of Germany. At the same time, regions about the medieval towns began to specialize
in garden produce and dairy products. Independent manorialism was also affected by the wars of 14th- and 15th-century Europe
and by the widespread plague outbreaks of the 14th century. Villages were wiped out, and much arable land was abandoned. The
remaining peasants were discontented and attempted to improve their conditions.
With the decline in the labor force, only the best land was kept in cultivation. In southern Italy, for instance, irrigation helped
increase production on the more fertile soils. The emphasis on grain was replaced by diversification, and items requiring more
care were produced, such as wine, oil, cheese, butter, and vegetables.
By the 16th century, population was increasing in Europe, and agricultural production was again expanding.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
The nature of agriculture there and in other regions was to change considerably in succeeding centuries. Several reasons can be
identified for this trend. Europe was cut off from Asia and the Middle East by an extension of Ottoman power. New economic
theories were put into practice, directly affecting agriculture. Continued wars between England and France, within each of these
countries, and in Germany consumed capital and human resources.
A new period of global exploration and colonization was undertaken to circumvent the Ottoman Empire’s control of the spice
trade, to provide homes for religious refugees, and to provide new resources for European nations convinced that only precious
metals constituted wealth.
Colonial agriculture was intended not only to feed the colonists but also to produce cash crops and to supply food for the home
country. This meant cultivation of such crops as sugar, cotton, tobacco, and tea, and production of animal products such as wool
and hides.
From the 15th to the 19th century the slave trade provided laborers needed to fill the large workforce required by colonial
plantations. Many early slaves replaced indigenous peoples who died from diseases carried by the colonists or were killed by
hard agricultural labor to which they were unaccustomed. Slaves from Africa worked, for example, on sugar plantations in the
Caribbean region and on indigo and cotton plantations in what would become the southern United States. Native Americans were
virtually enslaved in Mexico. Indentured slaves from Europe, especially from the prisons of Great Britain, provided both skilled
and unskilled labor to many colonies. Both slavery and serfdom were substantially wiped out in the 19th century. See Peonage;
Plantation; Slavery.
When encountered by the Spanish conquistadors, the more advanced Native Americans in the New World—the Aztec , Inca, and
Maya—already had intensive agricultural economies, but no draft or riding animals and no wheeled vehicles. Squash, beans,
peas, and corn had long since been domesticated. Land was owned by clans and other kinship groups or by ruling tribes that had
formed sophisticated governments, but not by individuals or individual families. Several civilizations had risen and fallen in
Central and South America by the 16th century.
The scientific revolution resulting from the Renaissance and the Age of Enlightenment in Europe encouraged experimentation in
agriculture as well as in other fields. Trial-and-error efforts in plant breeding produced improved crops, and a few new strains of
cattle and sheep were developed. Notable was the Guernsey cattle breed, which is still a heavy milk producer. Land enclosure
was increasingly practiced in the 18th century, enabling individual landowners to determine the disposition of cultivated land and
pasture that previously had been subject to common use.
Crop rotation, involving alternation of legumes with grain, was more readily practiced outside the village strip system inherited
from the manorial period. In England, where scientific farming was most efficient, enclosure brought about a fundamental
reorganization of land ownership. From 1660 large landowners had begun to add to their properties, frequently at the expense of
small independent farmers. By the mid-19th century the agricultural pattern was based on the relationship between the
landowner, dependent on rents; the farmer, producer of crops; and the landless laborer, the hired hand of American farming lore.
Drainage brought more land into cultivation, and, with the Industrial Revolution, farm machinery was introduced.
It is not possible to fix a clear decade or series of events as the start of the agricultural revolution through technology. Among the
important advances were the purposeful selective breeding of livestock, begun in the early 1700s, and the spreading of limestone
on farm soils in the late 1700s. Mechanical improvements in the traditional wooden plow began in the mid-1600s with small iron
Introduction to Agriculture Notes prepared by: Aqleem Abbas
points fastened onto the wood with strips of leather. In 1797, Charles Newbold, a blacksmith in Burlington, New Jersey,
reconceived of the cast-iron moldboard plow (first used in China nearly 2,000 years earlier). John Deere, another American
blacksmith, further improved the plow in the 1830s and manufactured it in steel. Other notable inventions included the seed drill
of English farmer Jethro Tull, developed in the early 1700s and progressively improved for more than a century; the reaper of
American Cyrus McCormick in 1831; and numerous new horse-drawn threshers, cultivators, grain and grass cutters, rakes, and
corn shellers. By the late 1800s, steam power was frequently used to replace animal power in drawing plows and in operating
threshing machinery.
The demand for food for urban workers and raw materials for industrial plants produced a realignment of world trade. Science
and technology developed for industrial purposes were adapted for agriculture, eventually resulting in the agribusinesses of the
mid-20th century.
In the 17th and 18th centuries the first systematic attempts were made to study and control pests. Before this time, handpicking
and spraying were the usual methods of pest control. In the 19th century, poisons of various types were developed for use in
sprays, and biological controls such as predatory insects were also used. Resistant plant varieties were cultivated; this was
particularly successful with the European grapevine, in which the grape-bearing stems were grafted onto resistant American
rootstocks to defeat the Phylloxera aphid.
Improvements in transportation affected agriculture. Roads, canals, and rail lines enabled farmers to obtain needed supplies from
remote suppliers and market their produce over a wider area. Food could be protected during transport more economically than
before as the result of rail, ship, and refrigeration developments in the late 19th and early 20th centuries. Efficient use of these
developments led to increasing specialization and eventual changes in the location of agricultural suppliers. In the last quarter of
the 19th century, for example, Australian and North American suppliers displaced European suppliers of grain in the European
market. When grain production proved unprofitable for European farmers, or an area became more urbanized, specialization in
dairying, cheese making, and other products was emphasized.
The impetus toward increased food production following World War II (1939-1945) was a result of a new population explosion.
A so-called green revolution, involving selective breeding of traditional crops for high yields, new hybrids, and intensive
cultivation methods adapted to the climates and cultural conditions of densely populated countries such as India, temporarily
stemmed the pressure for more food. A worldwide shortage of petroleum in the mid-1970s, however, reduced the supplies of
nitrogen fertilizer essential for the success of the new varieties. Simultaneously, erratic weather and natural disasters such as
drought and floods reduced crop levels throughout the world. Famine became common in many parts of Africa south of the
Sahara. Economic conditions, particularly uncontrolled inflation, threatened the food supplier and the consumer alike. These
problems became the determinants of agricultural change and development.
Many of the innovations introduced to agriculture by the scientific and Industrial revolutions paved the way for a qualitative
change in the nature of agricultural production, particularly in advanced capitalist countries. This qualitative change became
known as industrial agriculture. It is characterized by heavy use of synthetic fertilizers and pesticides; extensive irrigation; large-
scale animal husbandry involving animal confinement and the use of hormones and antibiotics; reliance on heavy machinery; the
growth of agribusiness and the commensurate decline of family farming; and the transport of food over vast distances. Industrial
agricultural has been credited with lowering the cost of food production and hence food prices, while creating profitable
Introduction to Agriculture Notes prepared by: Aqleem Abbas
businesses and many jobs in the agricultural chemistry and biotechnology industries. It has also allowed farmers and
agribusinesses to export a large percentage of their crops to other countries. Farm exports have enabled farmers to expand their
markets and have contributed to aiding a country’s trade balance.
At the same time, industrial-scale agriculture has had adverse environmental consequences, such as intensive use of water,
energy, and chemicals. Many aquifers and other water reservoirs are being drained faster than they can be renewed. The energy
required to produce nitrogen-based synthetic fertilizers, to operate heavy farm equipment, to manufacture pesticides, and to
transport food over long distances involves burning large amounts of fossil fuels, which in turn contribute to air pollution and
global warming. The use of synthetic fertilizers has affected the ability of soil to retain moisture, thus increasing the use of
irrigation systems. Fertilizer runoff has also stimulated algae growth in water systems. Finally, herbicides and insecticides in
many cases have contaminated ground and surface waters. See also Environment.
During the 20th century, a reaction developed to industrial agriculture known as sustainable agriculture. While industrial
agriculture aims to produce as much food as possible at the lowest cost, the main goal of sustainable agriculture is to produce
economically viable, nutritious food without damaging natural resources such as farmland and the local watershed. Examples of
sustainable agricultural practices include rotating crops from field to field to prevent the depletion of nutrients from the soil,
using fertilizers produced naturally on the farm rather than synthetic products, and planting crops that will grow without needing
extensive irrigation. Sustainable agricultural practices have seen great success in parts of the developing world where resources
such as arable land and water are in short supply and must be carefully utilized and conserved. See also Organic Farming.
Application of principles, of physical, biological and social science to growing domesticated plants
to meet a diversity of human need in a profitable manner. It is a challenge to increase yield as
population increases. It must be sustainable. (to use current resources in a way to safe guard future
use of these resources)
Why we study field crop production
To increase production.
To bringing more area under cultivation.
Dependence of agriculture
In 1951 it was 82%.
While in 1991 it was 70 %.
Share of agriculture in GDP
In 1951 it was 53.2%.
In 1998 it was 26 %.
In 2008-2009 it was 22.32 %.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Two ways to increase production sharing in GDP
1. Extensive cultivation
To produce crop using more resources particularly land.
2. Intensive cultivation
To produce crops by less resource particularly land.
Reason for low productivity Or Factors affecting crop productivity
1. Climate it is general weather conditions prevailing in an area over a long period.
2. Soil it is upper layer of earth in which plants grows.
3. Socioeconomic
Some crops can be grown in one climate while other can be grown in other climates. Some
factors of climate can be manipulated e.g. irrigation makes desert bloom while some climatic
component can not be manipulated.
Major component of climate
Most crop need optimum temperature.
Hydrophytes e.g. rice need a lot of water for optimum growth
Mesophytes some crops need moderate quantities of water
Can get low quantities of water e.g. grain sorghum
Soil is medium for crop growth. It provide water, nutrients and also oxygen for root respiration.
Some crops can be grown in heaviest soil (more clay than silt e.g. potato
Some crops grow in lightest soil e.g. sugarcane
Relating to or concerned with the interaction of social and climatic factors.
Inflexible surface irrigation system
Small land holding,
Inequitable land distribution and indigenous technology, poor quality of research and extension
and other essential services.
Cultivation of crops
There is a big gap (yield gap) in potential yield of crop.
Yield gap = potential yield –average yield.
For mustard we get only 1/3 of potential yield.
Potential yield
It is maximum possible achievable yield of crop.
Average yield.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Currently achieving yield.
Requirement of improving
Or developing crop productivity
Solving agriculture problems
National level policy
Specific strategies
Farming system approach
Improve marketing system
Modern technology
Solving agriculture problem
Major part of Pakistan’s agriculture land is situated in arid and semi arid regions.
Means excess of salt
Excess of sodium ions
Irrigation losses are 59 percent in Pakistan. Seepage (leakage of water) is about
24 percent.
Ill manner water sources (canals)
Inadequate water distribution or drainage
Lack of inputs or timely supply of inputs
Solving of problems
Solve these problems other due to water harvesting or storage, control of
seepage, control of evaporation, water harvesting and storage, control of seepage,
prevention of evaporation properly designing water canals (shape, design of
National level policy
We have three priorities
Policy should be national food security.
Full employment to rural area.
Expanded foreign exchange (exports)
Specific strategy
Regulate support price (fix price by government) for inputs and out puts
Import and export duties
Fertilizers recommendation
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Establishing soil labs in different zones.
Modernizing agriculture
Diversifying agriculture means to practice different crop on same land. Rural
employment opportunity.
Farming system approach
Is to modify and generate technology to increase productivity for identified groups of
farmers. It can be done to work for entire field through using farming system. To develop
technology according to the local climate and farmer participation.
Improving marketing system
To improve marketing system government as well as private sector should participate.
Government should regulate rules for marketing.
Modern technology
We should have modern technology.
The variability in field or plot size has greater influence on the research conclusion. The
conversion of one form of unit to other form need serious attention. Otherwise it will
result in a big mistake in formulating and recommendation of agricultural technology.
One hectare 10000 meter square.
One hectare 2.47 acre
One acre 2 jareb
One jareb 4 kanal
One kanal 20 marla
One kanal 505.meter square
One marla 272.25 ft
One meter 3.28 feet
English units of weight (ounces, pounds, and tons)
One meter 3.28 feet One gram .0353 ounce or
.0022 pound or lb
One meter 39.37 inches One kg 2.2 pounds
One inch 2.54 cm One quintal 100 kg
One kilometer 1000 meter One metric ton 1000 kg
One mile 1.69km One ounce 28 g
One meter cub 1000 liters
One liter .2201 gallon
One cubic feet 23.32 liter
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Classification, in biology, identification, naming, and grouping of organisms into a formal
system based on similarities such as internal and external anatomy, physiological functions,
genetic makeup, or evolutionary history. Most plants are usually known by their common local
name, which are different from country to country, locality to locality. For example pumpkin
refer to species cucurbitaceous in America while in Britain pumpkin refer to any of several
species of squash. In order to avoid confusion and to facilitate international communication, in
scientific writing, a plant is given one name …………it’s scientific, technical, or botanical name.
According to international accepted rule, each plant has a two words or binomial name given in
Latin. The first name refers to the Genus and second to Species. The initial of the person
(authority) who names a plant species or variety is listed after the species name. for example in
the name Triticum aestivum L.
L means Linnaeus who named the wheat plant. Generic name always begins with a capital letter
while species name with lower case letter. These names are underlined If written by hand or type
writer and italicized when printed.
1. To identify related species for different purposes like feed, food and fiber.
2. To gave reference to avoid any confusion in identification.
3. Common names for some plants in different localities are different or some
where it is extent so single (technical) anme is given for scientific purposes.
4. Classification was initiated by Theophrastus in 370 BC. Later on Carolous
Linnaeous a Swedish botanist (1707-1778) has introduced a two name system for
classification and divided plants on he basis of similarities and differences.
According to him there are four groups of plants
1. Thallophyta
2. Bryotphyta
3. Pteriodeiophyta
4. Spermatophyte.
They may be single cell, rope cells or thallus
They are called lower plants.
They don’t have roots, stems or leaves.
e.g. bacteria, algae and fungi
They have importance.
They fix nitrogen. They are harmful and cause diseases e.g. rust
Introduction to Agriculture Notes prepared by: Aqleem Abbas
They are small green plants. They grow on wet places. Roots are not true called
rhizoids. Stem and leaves are present. Have no agronomic importance e.g. mosses,
liverworth, hornworth.
They don’t have flower and seeds but reproduce by spores. They don’t have
agronomic importance except as ornamentals. They have vascular bundles so called
vascular plants.
E.g. ferns, horse tail
They are highly developed plants. They have leaves, stems, roots as well as having
flowers. All have agronomic importance.
In which seeds are not covered e.g. pine
In which seeds are covered in ovary
Angiosperms are divided into two group on basis of cotyledon.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Monocotyledon Dicotyledonous
Single cotyledon Two cotyledons
Narrow or needle like leaves Broad or web like leaves
Hypogeal germination Epigeal germination
Endosperm (2n) Endosperm (3n)
e.g. maize, wheat e.g. pea, grain, cowpea
Group of plants that normally breed among themselves and have many characters
common or a group of living organism consisting of similar individuals capable of
exchanging genes or of interbreeding.
Is group of similar plants within a particular species that is distinguished by one or
more than one character and given a name.
Cultivars of self pollinated plants as the pea or tomato usually constitute inbred lines
or pure lines that breed naturally. Cultivar name is always capitalized but never
underlined or italized. It may be identified as cultivar by single quotation mark e.g.
Golden Delicious.
It is working unit for agronomist and breeders.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Group of similar species.
For example
Species aestivum
Genus Triticum
Family graminae
Order graminales
Subclass monocot
Class angiosperm
Division spermatophyte
Kingdom plantae
Variation within a species form a variety. It has DUS characteristic means distinct,
uniform and stable characteristic. For example mexico pak, saleem, ghaznavi.
Botanical variety
It is a naturally occurring variety. Variation in it are because of nature. It is also
called wild variety. Different from originally developed. It is unidentified or
unnamed. When a group of plants occurring in nature in diffent form and botanical
binomial is not enough to identify it called botanical variety.
Variety under field or cultivate variety e.g. mexico pak is a variety not cultivar
because now a days it is not cultivated. Saleem is a variety as well as a cultivar. So
all cultivars are varieties but all varieties are not cultivars.
Variety may be
Introduction to Agriculture Notes prepared by: Aqleem Abbas
An organism or cell or a group of organisms or cells produced asexually from one
ancestor to which they are genetically identical. E.g. by vegetatively i.e. cutting,
budding, grafting, layering.
It is also called if it is produced (by seed)
It is produced by pure breeding that is self pollinated. E.g. called pure line.
Open pollinated variety
They are reproduced by cross pollination in field. It is done automatically. E.g. maize
Hybrid variety
It is created artificially or manually by controlled crosses. Cross pollination should be
done each time to develop hybrid. It is more vigorous form.
Fertilizer, natural or synthetic chemical substance or mixture used to enrich soil so as to promote
plant growth. Plants do not require complex chemical compounds analogous to the vitamins and
amino acids required for human nutrition, because plants are able to synthesize whatever
compounds they need. They do require more than a dozen different chemical elements and these
elements must be present in such forms as to allow an adequate availability for plant use. Within
this restriction, nitrogen, for example, can be supplied with equal effectiveness in the form of
urea, nitrates, ammonium compounds, or pure ammonia.
Virgin soil usually contains adequate amounts of all the elements required for proper plant
nutrition. When a particular crop is grown on the same parcel of land year after year, however,
the land may become exhausted of one or more specific nutrients. If such exhaustion occurs,
nutrients in the form of fertilizers must be added to the soil. Plants can also be made to grow
more lushly with suitable fertilizers.
Of the required nutrients, hydrogen, oxygen, and carbon are supplied in inexhaustible form by air
and water. Sulfur, calcium, and iron are necessary nutrients that usually are present in soil in
ample quantities. Lime (calcium) is often added to soil, but its function is primarily to reduce
acidity and not, in the strict sense, to act as a fertilizer. Nitrogen is present in enormous quantities
in the atmosphere, but plants are not able to use nitrogen in this form; bacteria provide nitrogen
from the air to plants of the legume family through a process called nitrogen fixation. The three
elements that most commonly must be supplied in fertilizers are nitrogen, phosphorus, and
potassium. Certain other elements, such as boron, copper, and manganese, sometimes need to be
included in small quantities.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Many fertilizers used since ancient times contain one or more of the three elements important to
the soil. For example, manure and guano contain nitrogen. Bones contain small quantities of
nitrogen and larger quantities of phosphorus. Wood ash contains appreciable quantities of
potassium (depending considerably on the type of wood). Clover, alfalfa, and other legumes are
grown as rotating crops and then plowed under, enriching the soil with nitrogen.
The term complete fertilizer often refers to any mixture containing all three important elements;
such fertilizers are described by a set of three numbers. For example, 5-8-7 designates a fertilizer
(usually in powder or granular form) containing 5 percent nitrogen, 8 percent phosphorus
(calculated as phosphorus pentoxide), and 7 percent potassium (calculated as potassium oxide).
While fertilizers are essential to modern agriculture, their overuse can have harmful effects on
plants and crops and on soil quality. In addition, the leaching of nutrients into bodies of water
can lead to water pollution problems such as eutrophication, by causing excessive growth of
vegetation.Fertilize calculation is done to provide optimum amount of nutrients to crops to
enhance crop production and quality, to increase farmer income to sustain soil fertility, to avoid
environment pollution.
Nitrogenous fertilizers N P K
Urea 46%
Ammonium sulphate . NH4SO4 21%
Ammonium nitrate. NH4NO3 35%
Phosphate fertilizers
Single super phosphate 18%
Triple supper phosphate 46%
Potash fertilizer
Sulphata potash K2SO4 50%
Murata potash KCL 60%
Compound fertilizers
DAP 18 % 46%
Nitrophosphate 23% 23%
Amount of fertilizer =
Amount of nutrient required(recommended by researcher) × 100
%age of nutrient in grade (in table
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Scientific names Sugar cane Sacchrum
flax Linum usittissimum cotton Gossipium
Jute Corchorus
sunhemp Cannabis sativas
sunflower Carthamus
Rape and
Brassica campestris
soybean Glycine max
pepper Capsicum annum
Cereal crops or grain crops or cereal grains
The most important food-energy source for three-fourths of the world population is grains. Most
grains are members of the grass family that are grown for their large edible seeds. Chief among
these are wheat, rice, corn (maize), barley, oats, rye, sorghum, and millet. All are widely used as
food for humans, both directly and in processed forms. Corn, barley, oats, and sorghum also
serve as livestock and poultry feeds; stalks and straw from these crops are important sources of
fodder (feed) and bedding for livestock. Grains are among the oldest crops, with their cultivation
dating from about 10,000 years ago.
Wheat, barley, oats, and rye are grown throughout much of the Temperate Zone world, most
commonly in areas with moderate to low annual rainfall (25 to 76 cm/10 to 30 in), where they
are more productive than crops that require more water. Higher rainfall, irrigation, and
fertilization, however, boost the yields of these cereal grains. Rice is primarily a tropical or
subtropical cereal, although Chinese and Japanese breeders have developed short-season strains
adapted to temperate areas. Most rice is grown in water or in paddies with ample water supplies.
Upland, or dry land, rice is grown in limited areas.
Sorghum historically has been a tropical grain, grown for food in Africa and Asia. In the past
half century its use has spread so widely that it has become an important livestock feed in dry
land (arid) areas such as the southwestern United States. Corn originated in subtropical climates,
but is now grown predominantly in temperate climates that have rainfall of more than 63 cm
(more than 25 in) per year. Rapid expansion of irrigation systems has made possible the
extension of corn acreage into drier areas in the central and western United States.
Grain crops are well adapted to mechanization. In the temperate zones most grain production is
on large farms, where machines till, plant, and harvest (see Agricultural Machinery). This is less
true in the Tropics and in locations where terrain is too rough for machinery. In these areas
Introduction to Agriculture Notes prepared by: Aqleem Abbas
grains are grown in small plantings. Here much of the planting, harvesting, and threshing
continues to be done by hand or with primitive equipment.
The development in the 1960s of improved grain-crop varieties with higher yields, stronger pest
resistance, and greater response to fertilizers has improved productivity throughout much of the
world. In many areas of the Tropics, the new developments triggered the so-called green
revolution, a dramatic increase in grain production. More work was needed, however, to adapt
superior varieties to local conditions and to solve human problems associated with the
distribution of their benefits. The energy shortage that began in 1973 led to a shortage of oil-
based chemical fertilizers and of fuel to run irrigation pumps, which also placed constraints on
further gains from the green revolution. These are grasses grown for their edible seed. They are
also called grain crops. Examples are sugar beet, wheat, maize, rice, sorghum, millet, and oat.
Rye (scale cereal), and sugar cane.
Forage crops
Forage-crop farming serves as the basis for much of the world’s livestock industries. Forage
crops are mowed, dried, and stored as hay; chopped and stored wet as silage; or fed directly to
cattle as pasture or as freshly chopped forage. In tropical and subtropical regions, most livestock
consume forages as pasture. In temperate zones, forages are commonly stored as hay or silage
for winter use.
Common legume forages of the temperate zones include alfalfa; red, white, and alsike clovers;
and birds foot trefoil. Popular grasses include timothy, orchard grass (cocksfoot), smooth brome
grass, tall fescue, and bluegrass. Forage-crop farmers normally grow one or more legumes in
association with a grass. Bacteria in the root nodules of the legumes convert atmospheric
nitrogen (see Nitrogen Fixation) into forms available to these plants and enrich the soil for the
grasses as well, thereby reducing the need for fertilizer and increasing the yields and the quality
of the forage.
These crops are grazed by animals or harvest as green chops, hay, silage. E.g. leguminosa (clover) have
three hundred types. Technically defined
Those crops which has dry matter greater than twenty fiver percent. For example barseem.
Fodder crops
When wheat, maize or other coarse grasses are harvested and cured for animal feed are know as fodder
crops. Most of the forage crops belongs to grass family or leguminous group. E.g. grasses and clovers
Silage crops
Partially fermented and succulent
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Soilage crops
they are green and succulent not cured(dried) directly feed to animals.
Fiber crops
These crops which are grown for their fiber for example textiles, rugs, ropes, kenaf,
Cotton Gossypium hirsute, Jute Corchorus capsularis, Flax Linum usitatissiumum, Kenaf Sun hemp
Sugar crops
Sugar is extracted from these crops e.g. sugar cane, sugar beet, and sweet sorghum.
Oil seed crops
These are crops which are grown for purpose of extracting oil from their edible seeds.
E.g. mustard, rape, ground nut, soybean, canola
Pulses or grain legumes
They are grown for their edible seeds. They belong to family leguminous. E.g. chickpea, pea, bean, and
Root and tuber crops
These are vegetables crops grown for underground parts for example
rhizopus ……………..garlic
root radish and carrot
Tuber potato
Bulb onion
Narcotic or drug crops
Have narcotic value
Have medicinal value
Poppy, tobacco, tea, coffee
Vegetables or garden crops
Grown for edible leaves e.g. lettuce
Grown for edible shoot e.g. okra, asparagus
Grown for edible flower e.g. cauliflower
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Grown for edible fruit e.g. tomato
Condiment crops
E.g. coriander, chili and mint.
Special purpose classification
Green manure crops
These crops are grown and ploughed under in green or manure stage to increase soil fertility e.g. dhancha
(guar), barseen, and brassica.
Silage or haylage crops
Silage crops are cut, and preserved in succulent condition. It is achieved by partial fermentation in silos.
E.g. oat, maize, soybean, sorghum, and grass arre called haylage crops. In Pakistan it is practiced only in
military dairy farms.
Soilage crops or green feed or zero grazing.
It is harvested when still green and succulent and are directly fed to animals without curing e.g. barseem,
shaftal, sorghum and maize.
Cover crops
They are grown to cover soil surface because to reduce soil erosion and nutrient losses by leaching e.g.
rye, grasses, mash, moth,
Catch crops
Catch crops are grown when the major crops failed or could not raise successfully due to some reason.
These crops are grown only for fodder not for yield. E.g. maize and sorghum for fodder purposes.
Companion crops
Companion crops increase soil fertility. Usually legumes are grown mixed with grass. These are those
crops growing two or three together. E.g. leguminosia plus gramminae. Companion crops increase forage
production and to improve quality.
Relay crops
When a major crops reach to reproductive or mature stage and is not harvested and a second crop relay
crop is sown in the field to increase crop intensity. E.g. planting of sugar beet in sugar cane.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Rabi cereals Grain legumes
wheat Triticum
aestivum L.
Cow pea Vigna
linsee Linium
Barley Hordeum
vulgare L.
lentil Lens culinaris Oil seed crops safflower Carthamus
Kharif cereals Grass
Soy bean Gycine max Rap see
Rice Oryza
sativa L
pea Pisum
jojoba Simmondisa
Maize Zeemays Mung
Vigna radiate Ground
sorghum Sorghum
Vigna mungo seesam Sesame
millet Pennisetum
caster Ricinus
Fodder crops
barseem Trifolium alex cowpea Vigna ungculita
Alfalfa /lucerna Medicago sativa
oat Avena sativa
Persian clover or
Sorghum Sorghum bicolor
Millet /bajra Pennisetum
Cluster bean
Legume crops (febacea /leguminosa)
They have pinnate leaves. They are those crops which have compound leaves or ovate leaves. They are
divided into forages and pulses
Pulses are annual leguminous crops yielding one to twelve grains. Play an important role in crop rotation
due to their ability to fix nitrogen. India is world largest produce and larger importer of pulses. Pulses
have twenty to twenty five percent protein by weight, which is double protein content than wheat and
three times than rice so pulses are called poor man’s nut.
Forage is plant material mainly plant leaves and stems eaten by grazing livestock. Historically term forage
has meant nay plant eaten by animals directly as Pasteur, crop residue or immature cereal crops. These
plants have trifoliate leaves for example clover
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Trifolium is a genus of about three hundred species of plants in pea family. They are small annuals,
biennials and short lived perennials herbaceous plants. Their leaves are trifoliate have red, pink while
purple flowers. E.g. shaftal (Trifolium resupinatum), Barseem ( trifolium alexandrium, Alfa alfa
(medicago sativus0
Rabi pulses Kharif pulses
Gram (chicken
Ciser aeritinum Mash(black gram) Vigna mungo
lentil Lens culinaris Mung bean, golden
gramm, green gram
Vigna radiate
peas Pisum sativum Cow pea Vigna unguculita
Pigeon pea(cajan
Cajanvas cajan
Cropping pattern
The distribution of farm area to various crops per year in any agro ecological zone.
Growing one crops again and again in a particular area is called monocropping.
Multiple cropping
Growing two or more than two crops on the same piece of land per year is called multiple cropping.
Growing two or more than two crops simultaneously at the same time with proper row to row
management or distance. E.g. sugarcane plus sugar beet
Mixed cropping
Growing two or more than two crops at the same time in which row to row distance is not maintained.
Oats plus mustard
Sequential cropping
Growing two or more than two crops in sequence on the same length per year. There are different types of
sequential crops.
Double cropping
In gilgit we have maize and wheat per year is called double cropping.
Triple cropping
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Quadruple cropping
Crop rotation
A crop rotation is growing crops in a regular sequence one after the other on the same land keeping in
mind that soil fertility may not be adversely affected
E.g. sugarcane than legume crops.
After the harvest of sugar cane under ground portion of crop is left in the soil to sprout another crop of
sugar cane. Sugar cane is vegetatively grown in Pakistan. Research show that sugar percent is greater than
fresh one.
A process by which plants take in and utilize food substances is called crop nutrition.
Taking in of food nutrients (inorganic substances from the soil by roots.
When these inorganic substance are being converted into organic form.
When these organic material is used by plants to obtain energy. Energy is used for growth and
development. Growth is increase in size while development in which leaves, stem and nodes arises.
Sixteen nutrients are essential. The crops are unable to complete its life cycle in the absence of essential
nutrients if the nutrients are deficient or absent plant cannot grow properly. The function of one essential
nutrient is not replaced by another nutrient. Nutrients are involved in plant metabolism nutrients must be
involved in plant metabolism.
Macro nutrients
Primary nutrients
C, H, O
Plant gets carbon from air while H and O from water.
N, P, K
These are primary nutrients are required by plant in more quantity. Therefore we called this nutrients
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Secondary nutrients
Ca, Mg, S
Are secondary nutrients these are present in soil to some extent. Therefore these nutrients are called
secondary nutrients.
Nitrogen is most important in all over the world
Cell division and cell enlargement
Important for vegetative growth.
Present in enzymes and proteins.
It is important for the protoplasm formation.
Nitrogen Is important for plumbness of seeds
Chlorophyll formation
Greenery of plants depends on nitrogen.
Deficiency symptoms of nitrogen
Leaves of plant become yellow due to deficiency of nitrogen. This process is called chlorosis.
Cell development and cell enlargement stops than plant has stunted growth.
Deficiency of nitrogen causes decrease in no of tillers and inflorescence and also decrease in protein.
Similarly quality of sed.
Excess of nitrogen
When nitrogen increases than the optimum will delay crop maturity.
Excess of nitrogen will increase plant height. It will cause lodging.
Excess of nitrogen in fiber crops decrease the fiber quality.
Excess of nitrogen in fodder crops is toxic to animals. Excess of nitrates cause cancer.
Excess of nitrogen is not economical to the farmers.
Excess of nitrogen increases impurities in sugar.
Phosphorous is second most important nutrients after nitrogen. It is component of energy rich
compounds. Phosphorous is also component of RNA and DNA. Phosphorous application to crops can
Introduction to Agriculture Notes prepared by: Aqleem Abbas
increase the size of seeds. It also helps in the formation of seeds and crops. Phosphorus applications
associated with early maturity.
Research shows that phosphorous resistant toward disease. It is also important for root development of
Deficiency of phosphorus
1. Less not of roots and plants will be stunted.
2. Will delay maturity.
3. Root proliferation.
4. Increase lodging.
5. Old leaves will be yellow if nitrogen is absent. While in absence of phosphorous
leaves will be dark green or purple.
6. Seed size will be reducing so yield will be reducing.
Potassium is very important for enzymes activation. It helps the plant in uptake of water. It increases
resistance to drought. It increases qualities of seed, food and other product of crops. Potassium is useful
for tobacco. Potassium increase oil quality in brassica. It increase shelf life of food products and play a
major role in resistant to diseases.
Enzymes become inactive.
Tip or margins of leaves will be red, white or yellow.
Plant absorb nitrogen only as inorganic nitrate No3 and in a few cases as ammonium NH4 or amimo NH2
IONS. Phosphorous is absorbed by plant as orthophosphate ions H2PO4- ION.
Any organic or inorganic material that is added to the soil to supply one or more than one nutrients
essential for the growth of plant.
Balance fertilizers
Balanced fertilizers are that fertilizer which is applied to the need or requirement of crop.
Fertilizer recommendation
1. Plant analysis
2. Soil analysis
3. Deficiency symptoms
Introduction to Agriculture Notes prepared by: Aqleem Abbas
4. Field experiments
Types of fertilizer
Straight or simple fertilizers
A fertilizer which contain only one essential nutrient. It is called straight fertilizer.
E.g. urea, SSP, and TSP
Compound fertilizer
A fertilizer which contain more than one essential nutrients is called compound fertilizer or
complex or called mixed fertilizer.
E.g. DAP, NP
Complete fertilizer
a fertilizer which contains all the three major nutrients is called complete fertilizer.
NPK = 15; 15; 15
But according to some scientist a fertilizer that contains all essential nutrients.
Methods of fertilizer application
Fertilizers are available in solid and liquid form so their method of application is different from
each other
Solid fertilizer
Standing crops
Basal dose
Basal dose
The fertilizer which is applied to crops in sowing time is called basal dose.
Band application
On the surface of soil uniformly by hand or by a machine
Band application
Application of fertilizer along the rows by drill or hand hoe machine.
Standing crops
Only the nitrogen or urea is used for standing crops.
For standing crops fertilizers are being used by following tow methods’
Top dressing
Fertilizers are used by hands or air crafts .
Side dressing
Along the rows by using hands or machines.
Liquid fertilizer
Liquid fertilizer is also applied in liquid form in advance countries. Fertilizer are applied in liquid
Direct application
Injection of fertilizer to the field or soil by special planters.
Application of fertilizers along with irrigated water .
Foliar application
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Spray of fertilizers on the leaves of crops
Root dipping
The treatment of liquid fertilizers with the roots of crops e.g. in rice treatment witn zinc sulphate
Seed priming
Treatment of crop seeds with nutrient solution for sometime before planting.
Classification on the basis of life cycle or crop duration.
On the basis of their duration or life cycle crops are divided into three groups;
Annual crops
These crops which complete their vegetative as well as reproductive stage in one growing season (year)
and produce flower and seed.
For example wheat, maize, and barley.
Biennial crops
Those crops which complete vegetative growth in first year and reserve food in roots or other plant parts
during second year the reserved food is utilized to produce flowers and fruits. E.g. sugar beet, radish,
carrot, and turnip. However these crops are usually harvested during first year to obtain commercial
Perennial crops
These crops grow for more than two years. They may produce seed each year but their life span is for
more than two years. These crops have the regenerative power to resprout from the stubble after cutting.
E.g. sugar cane and alfalfa.
Fertilizer requirement kg per hectare
nitrogen Phosphorous Potassium
Wheat irrigated 135 60 60
Wheat barani 80 40 40
Rice basmati fine 100 60 60
Rice coarse 140 60 60
Maize 120 60 60
Cotton 120 60 60
Tobacco 35 70 70
Sugar cane 170 70 160
Sugar beet 90 100 60
Pulses 25 60 0
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Classification on the basis of season
In Pakistan we have four distinct seasons like summer, winter, spring and autumn. However plants are not
classified according to seasons. Crops classification is based on planting date, water charges and govt
revenues. Crops are divided into two major seasons
Kharif crops
These crops which are planted in the summer months from march to july and harvested in autumn or
winter are called kharif crops e.g. maize, rice, sorghum, milet.
Rabi crops
These crops are planted in winter from October to December and harvested in summer from March to
may. Examples are wheat, barley, gram and lentil. However crops which deviate from these two
categories are termed as zaid kharif crops and zaid rabi crops.
Zaid kharif crops
These crops which are planted in august –September and harvested in dec-january e.g. toria (brassica
Zaid rabi crops
These are crops which are planted in February and harvested in May-June is called Zaid rabi crops e.g.
Purity analysis and adjusting the seed rate for a specific crops
Objective of practical
To investigate the percent composition of seed sample and to identify the main component of seed sample
that is pure seed, other seed, inert material and also to calculate the adjusted seed rate for a particular crop
Pure seed
Those seeds which dominate the seed sample a lot. It includes 1. Immature 2. Undersize 3. Shrivel 4.
Germinated. Pure seed belong to a particular variety.
Other seeds
We will take all those seeds other than pure seed or all those seeds which donot belong to pure seeds.
Inert materials
All those materials or matter which is neither pure seed nor other seeds.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
For example
A wheat sample five hundred gram having four hundred and thirty three gram pure seed, twenty five gram
other seed, and forty two gram inert material. Than calculate percent purity.
Percent purity = pure seed weight/sample wheat ×100
433/500×100 =87%
In 100 kg wheat sample 87 percent pure seed or purity.
We do purity test to adjust seed rate because the market seed are not hundred percent pure or hundred
percent germinable.
When plumule comes out of soil surface is called emergence.
The protrusion of radical and plumule of seed.
Adjusted seed rate:
Market seed are not 100% pure or 100% germinable. Thus seed rate higher than recommended seed rate
is used for uniform crop growth and stand. It is calculated as
Adjusted seed rate = normal (recommended) seed rate/useful seed rate
Useful seed rate= %purity ×%germination /100
Percent germination
Percent germinated seed out of total seed.
%Germination = germinated seed/total no of seed ×100
Classification based on climate
Based on different climatic factors (light, temp etc) plants are classified as;
Temperate zone crops
These crops are winter hardy and tolerate very low temperature. Around the world these plants grow in a
belt between 30 and 50 north and south latitude. They even existed a tropic of high altitude e.g. chitral,
kalam, gilgit . Some of these crops require chilly temperature e.g. wheat, oat, barley, rye, and rice.
Tropical zone crops
These crops grow between 20 norths and 20 south latitude where frost does not occur during the growing
season. Normal growth is affected by temp below 10 degree centigrade and plants are killed at freezing
Introduction to Agriculture Notes prepared by: Aqleem Abbas
temperature e.g. sugar cane, mango, banana, papaya, pineapple, cotton, mango, maize, rice, millet,
sorghum, sugar can
Subtropical crops
These crops tolerate some sub freezing temperatures but cannot grow well in temperate or tropical zones.
Subtropical belt includes both humid and semi arid zones. Subtropical fruit plants are killed by temp
below -7 degree centigrade e.g. citrus, date, fig, and pomegranate.
Plants grown vegetatively produce leaves and branches, then change from vegetative to reproductive
stage by producing flowers and fruits. This change is brought about by changes in day length i.e. number
of hours of light. Crops are classified according to their responsive to day length which is known as
Short day plants
Short day plants are those plants which change from vegetative to reproductive stage when day become
short for example rice require less than fourteen hours.
Long day plants
They change from vegetative to reproductive stage when the days become longer e.g. wheat, barley,
greater than fourteen hours.
Day neutral plants
Plant whose initiation of flowering is not affected by the length of days e.g. tomato, cucumber and okra.
Classification of crops on basis of growth habit
Based on vegetative and reproductive mode plants are classified into
Determinate plants
Those who initiate their reproductive stage after completion of vegetative stage . They can be harvested
only once. E.g. wheat, rice and maize.
Indeterminate plants
These are those crops which continue simultaneously both vegetative and reproductive stage at the same
time on the same plants. These plants have both mature and immature fruits, flowers and buds on the
same plant at a time.
For example
Soybean, mung bean, pea, tomato, cucurbits
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Agro meteorology
The word meteorology is derived from lating word metro-atmosphere and logos means science. The
science of atmosphere is called meteorology.
Agro meteorology
It is a science that deals with the atmospheric condition which is significant for agriculture.
A thin layer of colorless, odorless and tasteless gases hold to the surface of earth.
Percent of gases
Nitrogen =78%
Oxygen =21 %
Argon =.93 %
Carbon dioxide = .03 %
Neon = .0018 %
Helium = .005 % etc.
Condition of atmosphere at a given place in a given time. Weather is related to smaller area e.g. village,
city, district. It is also related to smaller for short time (day or part of the day), hot day, and cold day, dry
Climate is the summation of weather condition over a given region or given zone related to years. From
fifty years we know Australia has cooler temperature than Pakistan.
Environment is the aggregate (total) of all external condition that influence life and development of an
Introduction to Agriculture Notes prepared by: Aqleem Abbas
The relationship between crops and environment is called agro ecology.
Agro ecological zone
Are large areas in which agriculture and socio-economic conditions are similar for agriculture. They are
ten in number.
Indus delta
This includes south Hyderabad to Arabian sea. This area is called Indus delta e.g. rice, sugarcane, pulses
and barseem
South irrigated plains
The area from Jacobabad to dado is called south irrigated plains. E.g. cotton, beet, mustard, and
Sandy desert
This area includes
Thar to cholistan and thar to mianwali. This zone is divided into east sandy deserat and west sandy desert.
E.g. guar, millet, sorghum and wheat.
Northern irrigated plains
Include those areas of Punjab which are irrigated by river Sutlej and Jhelum.
In kpk from Peshawar to mardan that area is called northern irrigated plain. E.g. sugarcane, sugar beet,
maize, tobacco, wheat, plum, pear
Barani land
Includes karak, atock, Rawalpindi, banu,
Wet mountains
This area includes upper hazara and swat.
Northern dry mountains. This area include gilgit, chitral and dir.
Western dry mountains
Bannu, zhob, quetta, pasheen, parachinar, wazirstan.
Dry western plateau
Chagi, coastal area of makran.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Suliman pediments
From DI khan to DJ khan.
Agro ecological zones of kpk
Kpk zones temp altitude rainfall areas
Moist mountainous
and sub mountanes
2-----35 1200-2300meter >600 mm per
Malakand, hazara
and upper kurum
Higher plains 4--38 600-1200 meter 600—750 mm
per year
Swabi, lower
kurum agency and
malakand agency
Plains of higher
7-----41 450---600 meter 500—600 mm Mardan division,
Peshawar division,
district charsada
Plains and sub
mountainous areas of
lower rainfall
7---41 300—800 meter 375---500 mm
per year
Nowshera tehsil,
part of peshawer
Arid plains 2-----43 150---300 meter < 250 mm Nizampura of
nowshera, karak,
laki marwat, DI
khan, south
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Land cultivation of Pakistan
Urban/rural distribution
Share urban 35 percent (2005 estimate)
Share rural 65 percent (2005 estimate)
Literacy rate Total 47.4 percent (2005 estimate) Female 32.4 percent (2005 estimate) Male 61.4
percent (2005 estimate) Education expenditure as a share of gross national product (GNP) 1.8
percent (2000-2001)
GDP by economic sector Agriculture, forestry, fishing 19.4 percent (2006) Industry 27.2 percent
(2006) Services 53.4 percent (2006Workforce share of economic sector Agriculture, forestry,
fishing 42 percent (2002) Industry 21 percent (2002) Services 37 percent (2002) Unemployment
rate 7.7 percent (2004
Cultivated area of Pakistan
22 million hectare
Rainfed = 5 million hectare
Irrigated area =17 million hectare.
Rainfed area of Pakistan
Punjab 14
Sind 30
Kpk 50
Baluchistan 25
Area of Pakistan 79.61 million hectare
forest 4.04 million hectare
Cultivated area 22.1 million hectare
export 65 %
Baluchistan total area 35 million hectare
Punjab total area 21 million hectare
kpk 10 million hectare
sindh 14 million hectare
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Crops of Pakistan % production in rain fed
Wheat 10
Maize 27
Millet and sorghum 56
Pulses 85
Ground nut 90
Rap and mustard 25
Domestic livestock 70
Pakistan is divided into four zones
Arid zone Rainfall less than 200 or 300 mm per year e.g.
baluchistan, sindh, DI khan, nowshera, gilgit,
Semi arid zone Rainfall 300-600 mm per year. Northern areas of
Punjab, Peshawar , mardan, charsada, deer, bajour,
Sub humid zone 600-1000 mm per year. Sialkot, Gujranwala,
parachinar, abotabad, swat
Humid zone Rainfall greater than 1000 mm. muree hill, upper
hazara, upper swat, and dir,
Eleven different ecological zone of Pakistan
Zone 2 E.G. GUJRAT
Zone 11 THAL
Kpk has 2 million hectare cultivated area. From this 1.05 million hectare area is rainfed and .95 million
hectare area is irrigated. Pujab has 16 million hectare is cultivated. Sindh only 4 million hectare and
Baluchistan is less than 1 million hectare.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Environmental factors are divided into five groups;
1. Climatic factors
2. Water factors i.e. hydrophytes, xerophytes and mesophytes
3. Topographic factors or slope or elevation
4. Edapic factors i.e. soil factors, soil structure, soil texture.
5. Biotic factors ; biotic factors are also important for growth and life of plants
Classification of crops on the basis of pollination
The transfer of pollen grains from anther to stigma of a flower. Based on pollination we have divide crops
into two types
Self pollinated crops or autogamy
These crops in which pollens are transferred into the stigma of same flower, different flower on same
plant and different flower on different plants of same cultivar. Self fertilized plants have close flower but
1 to 3 percent cross pollination can be occurred.
For example wheat, barley, rice and soybean
Cross pollinated crops (allogamy)
Transfer of pollen grains to stigma of different cultivars. It is carried out by insect, wind and water. They
have open type flower. Cross pollination occur to an extent of 96 percent e.g. maize, safflower, sunflower,
and brassica. Cross pollination by wind is called anemophily while by insect it is called entomophily.
Some reasons for allogamy
1. Self incompatibility
2. Dichogamy a. protandry (pearl millet) anther ripe before carpel. B. protogamy.
3. Cytogenetic reasons. A. translocation, aneuploidy, autopolyploidy.
4. Hetrostyle
The situation in which the stamen and style of unequal length for example
Pinflower have long pistil and short anthers.
Thrumb flower have long stamens and short pistil.
Floral mechanism
Their flower donot open and are internally pollinated and fertilized. It is
When pollination occurs after opening of flower. It may be autogamy or
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Based on propagation
More plants are produced from single desirable plants to preserve its characteristic. A successful method
is one that transferred all the desirable characters.
Sexually propagated.
These crops are propagated by seeds. Most common for example wheat, maize etc.
Asexually propagated plants
Propagated by using special parts or using certain techniques like cutting, grafting, budding and layering
e.g. sugarcane, potato
Modes of photosynthesis or plant efficiency
This classification is based on the effective utilization of resources and mode of carbon dioxide fixation
1. C3 plants or inefficient plants
2. C4 plants or efficient plants
3. Crassulation acid metabolism plants
C3 plants or inefficient plants
During photosynthesis, some plants fix carbon dioxide and form a three carbon molecule called 3-
phosphoglyceric acid. This pathway was first worked out by calvin and his co-workers(basham and calvin
1957). Plant with this pathway of carbon-assimilation is called C3 pathway plants. Such plants cannot
utilize carbon dioxide, light, temperature and water efficiently. Therefore they are called inefficient plants
e.g. wheat, oat, rice, soybean, rye , banana, cotton
C4 plants or efficient plants (hatch and slack)
Another pathway of carbon dioxide fixation was found in some plants by Hatch and Slack (1966). In
these plants the first product of photosynthesis is a four –carbon molecule. Plants which fix carbon
dioxide in this way have no photorespiration and make efficient use of carbon dioxide, light, temp and
water. Therefore these plants are called efficient plants. E.g. sugarcane, maize, sorghum.
Crassulation acid metabolism
Cam plant fix carbon dioxide into 4-carbon acids as do the c4 plants but fixation of carbon dioxide occurs
at night when the stomata are open. Typical cam plants grow in deserts and have succulent fleshy leaves
and stems with low transpiration and water requirement e.g. pineapple, prickly pear and cactus.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Classification of the basis of nutrients uptake
Crops vary in their nutrient requirements some crops add to soil fertility while others deplete the nutrient
Restorative crops
These are crops which return nutrients and organic matter to the soil. For example barseem, alfalfa and
Exhaustive crops
Crops which feed heavily on the soil and deplete soil nutrients e.g. sorghum, tobacco and sunflower.
It records the temperature of air and soil.
It also records temperature on the graph paper. It is automatic
It measures or record humidity of the air.
Measure or record humidity on the graph paper. It is also automatic.
It records wind speed.
Sky wane or wind wane.
It records duration of wind.
Evaporation pan.
It measures or record evaporation or loss of water from soil surface.
Sunshine record
It records duration of sunshine,
Mechanical phonograph it records intensity of light.
Rain gauge
Introduction to Agriculture Notes prepared by: Aqleem Abbas
It records or calculate amount of rain fall.
Irrigation methods.
Irrigation, artificial watering of land to sustain plant growth. Irrigation is practiced in all parts of
the world where rainfall does not provide enough ground moisture. In areas of irregular rainfall,
irrigation is used during dry spells to ensure harvests and to increase crop yields. Irrigation has
greatly expanded the amount of arable land and the production of food throughout the world. In
1800 about 8.1 million hectares (about 20 million acres) were under irrigation, a figure that rose
to 41 million hectares (99 million acres) in 1900, to 105 million hectares (260 million acres) in
1950, and to more than 273 million hectares (675 million acres) today. Irrigated land represents
about 18 percent of all land under cultivation but often produces over twice the yield of non
irrigated fields. Irrigation, however, can waterlog soil, or increase a soil's salinity (salt level) to
the point where crops are damaged or destroyed. This problem is now jeopardizing about one-
third of the world's irrigated land.
1. Surface irrigation
2. Sub surface irrigation
3. Sprinkle irrigation
4. Drip irrigation or trickle irrigation
Surface irrigation
In surface irrigation water is applied on the surface of soil.
Kinds of surface irrigation
1. Basin irrigation
2. Furrow irrigation
3. Border irrigation
Basin irrigation
In basin irrigation water is applied to the entire field for example supply of water to whole field.
e.g. barseem, shaftal, wheat.
Furrow irrigation
In furrow irrigation water Is applied to the plant rows in the small water channels. E.g. cabbage, maize
and tomato
Border irrigation
In border irrigation water is applied to the crops or field in small strips e.g. shafta. Agroforestary trees.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Sub-surface irrigation
In sub surface irrigation water is applied from below ground surface to the roots of plants.
E.g. karez system.
Sprinkle irrigation.
Water is applied in the form of spray or foliar application.
Drip or trickle irrigation
When water is applied to the plants roots in small plastic pipes only.
Mechanical manipulation of soil aimed at improving the physical condition of the soil. Tilth is physical
condition of soil resulting from the tillage.
Objectives/Advantages of tillage
It improves soil structure vs. texture.
Soil structure
The aggregate of soil particles is called soil structure. Results show that round structure is good for
Soil texture
Relative proportion of clay, silt and sand is called soil texture.
Removing of weeds or stubbles.
For the decomposition and incorporation of organic matter (plant residues)
Increase multiplication of nitrogenous bacteria.
Destroy the eggs of insect and pest.
Tillage is also important for incorporation of organic and inorganic matter.
Tillage is also important for control of soil erosion.
Water infiltration in the soil increases as a result water runoff decreases and it
will decrease soil erosion.
Improve the temp of soil.
Increase water conservative.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Disadvantage of tillage
1. Extra lost, extra energy, labor and time is required.
2. Sometime it also destroys the soil particles or soil structure.
3. Intertillage damage crops
4. Higher decomposition of organic matter.
5. Tillage operation will increase the no of weeds.
6. No of microorganism will also increases.
Tillage operation
Tillage operation changes from area to area it is because of soil type, cropping pattern, soil moisture
content and climatic factors.
Types of tillage:
1. On seasonal tillage
2. Off seasonal tillage
3. Special purpose tillage
On seasonal tillage consist of Preparatory tillage and Intertillage
Preparatory tillage has two types
Primary tillage
Secondary tillage
On seasonal tillage
Tillage operation performed for sowing of seasonal crops
Preparatory tillage
The tillage we prepare soil for growing of crops.
Primary tillage
After the harvest of crops usually deep tillage is practiced.
e.g. desi and mesion plough, mould board plough, disc plough, subsoiler and rotavater.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Secondary tillage
By which soil bed is prepared.
Sohaga conventional
Disc harrow
Cultivater or tiller
Is that tillage operation when the seed is present in soil till maturity . it is performed after planting of
plants e.g. earthing, thining and weeding.
Off seasonal tillage includes Post harvest tillage summer tillage, Winter tillage and Fallow tillage
Off seasonal tillage
Tillage operation required for soil conditioning but not for the immediate sowing of crops.
Post harvest tillage
After harvest crops we don’t want to sow seed but we want to prepare our land only weeds and stubbles
are removed. It is also important for conservation of rain water.
Sumer tillage
Is practiced in tropical zones.
Winter tillage
Is practiced in temperate zone.
Fallow tillage
Leaving the arable land un cropped for one season or for more than one season due to some reasons.
Special purpose tillage
Tillage operations performed for specific purpose is called special purpose tillage.
It is also called deep tillage. Sub soiling is done once three to five years to break the hard pan below the
plough layer. It is also called chiseling
Tillage operation is used to convert un even land to smooth, see bed.
Blind tillage
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Cultivating the soil with shallow tillage implements before the emergence of crop. It is practiced when
germination is delayed due to some reasons.
Clean tillage
Tillage operation in which no plant is left undisturbed is called clean tillage. In clean tillage weeds are
removed from crops.
Deep tillage is used to incorporated to destroy crops as well as weeds.
Mulch tillage
Tillage operation in such a way that plant residues(stubbles) or other mulch material (plastic, stones) are
left on soil surface is called mulch tillage.
This tillage is implemented where temperature is high, availability of water is low.
Contour tillage
Tillage operation along the contour in order to reduce run off (speed of water).
Wet tillage
It is also called puddling. Tillage operation in standing water in order to produce an impervious layre.
This layer reduces percolation and leaching fertilizers.
Minimum tillage or zero tillage
Concept of minimum tillage was started in united state in 1974 because of high costs of oil prices.
Minimum tillage is aimed at reducing tillage to minimum which is necessary for good seed bed, rapid
germination, satisfactory plant stand and favorable conditions. It is against primary and secondary tillage.
Tillage operation can be reduced by two ways.
By omitting operations which don’t give much benefit and are very costly.
Combining tillage operations by combine drill.
1. Lesser seed germination.
2. Germination percent decreases.
3. Poor root development.
4. Poor nodule formation.
5. Reduce the rate of decomposition of organic matter.
6. In minimum or zero tillage weeds are controlled by herbicides but continuous use of herbicides
cause pollution. Zero tillage refers to growing of crops with least soil disturbances in which
unwanted crops are controlled by herbicides.
7. The seed is planted directly into the soil with special planting equipments (diplers).
8. Zero tillage is used in high erosion areas.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Dry land agriculture
Growing of crops under rainfed condition is known as dry land agriculture. Most fifty percent kpk
is rainfed. Depending on the amount of rainfall dry land agriculture is divided into three
categories. Dry farming, Dry land farming and Rainfed farming
Dry farming
Cultivation of crop in those areas where rainfall is less than 750 mm annually.
Dry land farming
Cultivation of crop in those areas where rainfall is greater than 750 mm .
Rainfed farming
Where rainfall is greater than 1100 mm.
Types of climate
Climate is hot or temperature is high throughout the year.
Summer is spring like while winter is freezing less than zero.
Summer very hot
Spring spring like
Winter is mild.
On the basis of rainfall
Rainfall is greater than 1000 mm per year.
Sub humid
That area where rainfall is between 600-1000mm.
Where rainfall is less than 250 mm.
E.g. thar in cholistan, thal in miawali.
Semi arid
Subtropical like temperature
250 mm to 600 mm rainfall per year.
Four types of barani cultivation practices.
1. Rainfed cultivation
2. Flood water cultivation or silabah farming
3. Rod kohi
4. Run off farming or khush kaha
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Rainfed cultivation
Where plants totally depend upon rainfall. This type of cultivation is practiced in gujrat,
Rawalpindi, miawali, swat, etc
Flood water cultivation
In this type of cultivation monsoon rainfall is stored in by deep tillage and then the residual
water is used for cultivation of wheat in winter.
Rod kohi
In this type of cultivation rainfall on hills are collected and then diverted toward the field.
This is practiced in DI khan, larkana, Dado, and some areas of Baluchistan.
Run off farming
This type of farming is practiced in Baluchistan where rainfall is less than 200 mm per year.
The rainwater is collected in the area which is called catchment area. It is also called kush
kawa. This practices are called water harvesting.
Problems of crop production in dry land of Pakistan.
1. Climatic factors
High temperature
2. Soil factors
Low organic matter, erosion, salinity or alkalinity.
3. Socioeconomic factors
Economic condition of farmer.
Lack of transport facilities.
Lack of market , storage, unemployment, and political unstablity.
4. Technological factors.
lack of modern technology in dry land.
Improvement in agri-dry land
Short term improvement
Long term improvement
Short term improvement
1. Introduction of new technology.
2. Availability of credits to farmers.
3. Loans availability.
4. Training of farmers (field dry)
5. Supply of seeds and fertilizers.
6. Availability of tillage implements.
Long term improvement
Planning in research to upgrade the existing developing infrastructure.
Digging wells and ponds.
Making small dams for collecting runoff water.
Provision of education
Health facilities
Communication and transport facilities
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Development of agro-forestry.
Green Revolution, term widely used since the 1960s to describe the effort to increase and
diversify crop yields in agriculturally less advanced regions of the world
plants grown for use: a group of plants grown by people for food or other use, especially on a large scale in
farming or horticulture
amount harvested: the amount harvested from a plant or area of land, during one particular period of time
a good crop of tomatoes
animals reared for produce: a group of animals reared in farming, or something produced from them
a poor crop of lambs
A community of plant grown for economic value under filed conditions. distribution of commercial crops
is governed by plant environment interaction and its adaptation is related to climatic factors, soil,
topography, pest and diseases of a particular region which fulfill the plant requirement for normal growth
and development. An agronomist has a key role in such situation. He can modify the production
technology of crops to adapt or can acclimatize the crops to new environment.
The feature of plant or crops which has survival value under existing climatic conditions or habitat. And
such features allow the crops to fully utilize the nutrients water, light etc for optimum growth.
Changing plant behavior by exposure several times to a new environment. We can say temporary
changing the phenotypic characteristic of a plant to adjust the new environment.
Production technology
It refers to raising of crops on a piece of land and cover all operations needed for raising a successful
crops. It includes land preparation, soil, fertilizer application, irrigation, weed/insect/pest management,
harvesting and finally storage.
Choice of crops
Modern agriculture is an industry and therefore it is important to asses the choice of crops or feasibility of
crops for a region. It needs basic knowledge of adaptability, basic production technology and socio
economic value of crops.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
General guidelines for successful crop production
1. Selection of cultivar
2. Field preparation
3. Manure application
4. Seed bed preparation
5. Inoculation
6. Commercial fertilizer.
Selection of cultivar
Select the recommended variety or cultivar for your area.
Barani is irrigated
Late vs. early
For feed or for storage
In general variety must be disease resistant and high yielding and adaptable to environment.
Field preparation
Field should be prepared at field capacity condition. The previous year stubble must be
incorporated and mix with soil.
Field capacity.
Moisture condition of soil after downward drainage of gravitational water.
After harvesting stubbles should be removed properly. In barani areas ploughing should be done
at proper time to conserve moisture. After ploughing the field is left as such to dry out the weeds.
Manure application
Incorporate fertilizer thirty to sixty days before sowing and should be well mixed there fore losses
of nutrients will be less.
Seed bed preparation
For final seed bed preparation the fields are irrigated for fortnightly and again plough at field
capacity condition. No of plowing depends upon crop nature whether it is cereal or sugar cane
crop. Cereal needs shallow plowing while sugar crops need deep plowing.
Use of or addition of rhizobia to soil or seed. Rhizobia are nitrogen fixing bacteria. When
legumes are sowing for first time rhizobia is not present in soil and should be applied from
external source for example Rhizobium japanicum is applied to soybean crops.
Commercial fertilizer
Fertilizers are applied pre-sowing i.e. potassium and phosphorus as a single dose where as
nitrogen is applied in split application half at sowing and other half at first or second irrigation.
Fertilizers must be well mixed into soil. In barani areas all type of fertilizer is applied before
sowing or after rainfall. Legume required less nitrogen fertilizer than other crops.
Nitrates is leaching while ammonia is volatile.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
In rotation of crops our main interest is fertility of soil while in sequential crop production is our
interest. The sequential growing of crops at a piece of land to improve productivity as well as soil
fertility is called crop rotation. It should be well planned. Legumes must be included e.g.
Wheat mungbean wheat
Maize gram tobacco
It is a prime importance. It must belong t refuted company. It has high purity and germination.
Sowing method
Planting it a recommended seed depth, seed rate and row to row and plant to plant distance. Seed
must be covered after sowing with soil. Appropriate methods should be used.
Line sowing
Sugarcane, maize, tobacco
Broad cast
Clover, sorghum, maize.
Kharif crops need more irrigation than rabi crops. Irrigation must be done at evening time avoid
water storage in plots.
Multi harvest crops
Some crops are multi harvest means gives us more than one single cut. After each cut plants or
fields must be irrigated and fertilized to increase its succlency e.g.
Barseem, shaftal and all types of clover.
The uprooting of extra plants from dense population is called thing. It is done to optimize plant
population . it should be practiced within a month of emergence . try to uproot weak and damaged
plant only. It is done to decrease input cost and to facilitate hoeing, and harvesting etc.
Thinning is based on crop nature that is morphology, crop duration and purpose of cultivation.
Long duration …..thining more
Short duration……..for fodder not thinning.
Control weeds as early as possible using herbicides or manually. It should be completed upto
reproductive stage. Use light implements and not too deep and frequent at field capcacity level.
Insect , pest and diseases
Check periodically for insects, pest and diseases control through pesticides. Disease resistant
cultivar is preferred.
Harvesting and storage
Harvest the crop at harvest maturity to increase quality, quantity and to avoid shattering.
Yellowing of leaves or drying of leaves and loss of green color is indication for crop harvest
Crop store the seed at proper moisture content
For oil crop seed store at moisture 4 to 8 %.
Other cereal seed 10 to 16 % moisture.
Store in dry and clean place. Fumigate the store house before storing crop seeds.
Physiological maturity.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
It is no further accumulation of dry matter through photosynthesis. At that time moisture content
is 30 to 40 percent.
Harvest maturity
When moisture reach to 8 to 20 percent and have maximum dry matter.
The edible grains are called cereal grain, grain crops. It includes in a family poacea or graminae
for example wheat, maize, rice, rye, millet, barley , sorghum and triticale.
Economic importance
1. It is used as a staple food for human through out the world.
2. It occupies about fifty percent of plow land in world.
3. In Pakistan it occupies about 54 % . it dominated world agriculture because it directly or
indirectly provide as major portion of human diet. It is the cheap source of calories uses as
feed and forages for live stock.
General characteristics of wheat
Local name gandum
Common name wheat
Scientific name Triticum aestivum
Growing season rabi
Mode of pollination
Photoperiod requirement
Long day plants
Special name king of cereal
Introduction to Agriculture Notes prepared by: Aqleem Abbas
adaptation Seed bed
Seed rate Method
of sowing
weeding yield diseases control varieties
Wide range of
climate and soil.
Soil loam or clay
4 to 5 times
plow and is
followed by 1-
2 planking.
Farm yard
manure 10-15
135,80,00 for
80,40,00 for
rainfed. All
is applied at
sowing while
nitrogen is
split half. Half
at first
while half at
Potash is
applied 60-80
kg per hectare.
15 dec.
area 15
oct to
16 nov.
100 to120
kg per
rainfed 60
to 80 kg
Line par
or drill
and khora
method is
old one.
Drill is
1 to 2
weeding is
enough. after
1st irrigation
for effective
irrigation is
done after 2
to 3 weeks of
Than growth
Than at
stage. Than
at boot stage
stage ), than
at earing or
stage. Than
milk stage
harvesting at
15 april to 15
may at plain
areas while
in hilly areas
it is done at
june or july
1000 to
1500 kg
2000 to
3000 kg
bard 1,
bard 2.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Local name
Botanical name zeemays
Growing seasons
Kharif and spring
Mode of pollination
Cross pollination
Short day plants
Economic importance
Use as a food, feed, oil crops
It is adapted to diversified climate and soil from near sea level to altitude of about 1300 feet. It also grows
in subtropical area or climate. It is grown from sandy to clay soil. The best soil is medium soil texture.
Cultural practices
Seed bed preparation
Four to five times plowing, followed by two to three plankings.
Farm yard manure at the rate of 15 to 20 tons per hectare. So maintain the soil. 40 to 50 days before
Nitrogen is applied at split.
NP 120, 50 kg per hectare is added.
Potassium and zinc play very important role and is added when soil test show deficiency.
Time of sowing
Spring from February to March
Kharif from May to June
Seed rate
Recommended seed rate is 30 kg per hectare for grain while recommended seed rate is 60 to 70 kg per
hectare for fodder.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
30 kg per hectare seed gives us 6000 to 70000 plants per hectare. Similarly plant to plant distance is 20
cm and row to row distance is 70 to 75 cm for grain maize and maintained via thinning.
Method of sowing
Maize is dual purpose crop either it is grown for grain or fodder. If it is used for grain we can use two
Plain bed or line
If we use for fodder, we use only plain bed method (broadcast)
Three to four times weeding is essential for higher products. Weeds can be controlled or either chemically
or mechanically (seeding)
Hand hoeing
Weeds must be controlled before tassel formation. Weeds are higher in summer crops than winter crops
due to favorable conditions. Thus must be controlled for improved productivity.
Maize is very responsive to water stress. Six to seven irrigation at ten to fifteen days interval. Most
critical stages of water supply.
Tassel formation
Forty percent yield reduction occurs if water stress is imposed at tassel formation stage.
Crops are harvested when
1. Leaves turn out dry.
2. Silk becomes brown or dark
3. Stalk of plant turn yellow
Moisture content at harvesting stage is twenty percent. Kept in plot, when
moisture reduce to 12 to15 percent, than cobs are removed and threshed after de
husking of cob.
Cobs……….ear plus leaves.
Ear…………grain portion without leaves.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Store in gunny bags on cemented floor in cool and dry places.
1500 to2200 kg per hectare.
Potential 7000 kg per hectare.
Kissan 92, azam, shaheen, Khyber, neelum, akbar.
Seed rot and seedling blight.
Root and stalk blight
Leaf spots
Ear and kernel rot
Insects or pests
Borers, armyworms and shoot flies.
Scientific name Oryza sativa
Local name chawal
Mode of pollination self pollinated crops
Photoperiod short day plant
Growing season kharif
Also called summer kharif crop.
Class monocot
Pady grain plus hull
Rice milled rice after dehulling
Root seminal plus adventitious
That root directly develops from seed.
Develop from first internodes above seeds.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
It is adapted to humid tropical climate which has plenty of rainfall, sunshine and high temperature. It is
adapted to heavy clay or clay loam soil . for its production PH range should be 4.5 to 8.5 . However grow
well in acidic soil due to major micro-nutrient availability.
We can store water in clay soil but we cannot store water in sand.
Sowing methods of rice.
Transplantation of nursery
Direct seeding
It is done in countries which has adequate water supply system. For transplantation we develop nursery
establishment. It must be completed before 20
may. It takes 25 to 40 days for its establishment. There
are three methods of nursery establishment.
Wet bed method
Dry bed method
Rabbi method
Wet bed method
Wet bed method is practiced in traditional growing area of rice. Fine texture soil in which clay content is
greater than sand. Plots are puddle and pre-emerged seed are broad casted. Seed rate is 20 to 40 kg per
hectare. High seed rate results in weak seedling whereas low rate encourage weed to sprout.
Dry bed method is practiced where the soil is loamy or silt loam and puddling is not possible. Plots are
prepared in dry conditions or field capacity level. Seed rate is 1.5 times higher than wet bed method.
Weeds control is not satisfactory.
Rabbi method is practiced in dera ghazi khan area where the soil is hard and seedling uprooting is
difficult. Nursery plots are prepared with spade and crop residue is spread and burnt a day before sowing
to loosen the soil. Seed rate is twice as compared to wet method. Weeds can be controlled satisfactory.
Small size seed ( basmati)
Coarse seed (mehran)
Seed rate is low for fine or small size seed (basmati than coarse seed)
Production technology
Land preparation
Introduction to Agriculture Notes prepared by: Aqleem Abbas
In dry condition, upland rice production. The land is plowed 2 to 7 times and than smooth it via planking.
In wet condition (low land) the soil is puddle, this puddling make an impervious layer which reduce water
Fertilizer and manure application
10 to 15 tons FYM is added a month before puddling. NPK 120,60,60 is used for fine varieties.
NPK 140,60,60 is used for coarse varieties.
Zinc is an important microelement is used at the rate of 12.5 kg per hectare i.e. znso4.
Cultural practices
Land preparation
Manure and fertilizers
Early transplantation causes sterility of plant due to increase in temperature at anthesis stage. Late
transplantation of seedling result in insects, pest and diseases attack as well as cause lower no of
production tiller due to shortening of vegetative period. Time range is from twenty June to fifteen July.
Good condition seedling 25-40 days old are transplanted. Two seedling per hill whereas 50 days older
seedling are transplanted two to four seedling per hill. Optimum plant production is 1000,00 plants per
In pady land, water is allowed to stand particularly for initial twenty five to thirty five days. In
transplantation the water level is kept at 3 to 4 cm, to avoid submerging of seedling. After a week, the
water level is rose upto 7 to 8 cm. exchange of water is done once a month. Fresh water should be
First month of transplantation is very critical for weed infestation and reduce yield upto fifty percent.
Uprooting the weeds at least twice is done.
Proper land management
Irrigation management
Can be used for weeds control.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
When panicle turn out yellow and lower grains are in hard drought condition. So fifteen days before
harvesting water is drained at. At harvesting moisture content of pady should be greater than twenty
percent. After harvesting paddy is kept for 4 to 5 days in plots for sun drying and than store in cool and
dry place.
Insect pest or diseases
Grass hopper
Leaf hopper
Plant hopper
Leaf hopper
Foot rot
Paddy blast
Stem and leaves blight.
Diazine 1.15 litre per hectare for insect
Topsin M is used for diseases
2 to 2.5 tons per hectare. Coarse varieties have higher yield than fine varieties.
Basmati 370
Basmati 385
Ir .6 mehran.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Parameters barley sorghum Millet
Local name jow jawar Bajra
Scientific name Hordeum vulgare Sorghum bicolor Penisatum typhodes
Pollination self self Cross
Photoperiod long short Short
Root system Fibrous fibrous Fibrous
Special characters Drought tolence
Efficicient water
Drought resistance due
to way leaves
Drought resistance
adaptation Cool,temperate,
tropical Hot and dry climate
soil Loam to silt loam All types of soil All types of soil
Cultural practises
No of ploughing 5-6 4-5 3-4
No of planking 1-2 2-3 1-2
Fertilizers NPK 50.25.0 100.50.0 80.40.40
Time of sowing Mid oct to mid nov 3
week of june-july June-july
Method of sowing Broadcast or drill Broadcast or drill Broadcast or drill
Row to row distance 20-30 60-00 50cm
Seed rate 50-60 6-8 6-8
weeding No need 1-2 1-2
Insect/pest/diseases Powdry mildew,smut
and rust
Army worm , aphids
Shootflies, borers.Leaf
spot, blight
Smut and blight
irrigation 2-4 2-3 2-3
harvesting March-april Nov-dec Sept-oct
Storage 15% moisture 12-13 % moisture <10 % moisture
yield 0.7-12 tons per hectare 0.2 to 0.4 tons per
0.2 to 0.3 tons per
cultivars Awarum
Frontier 87
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Whose grains are edible purposes.
The dehuled grain legume
Importance of legume
1. Cheap and excellent source of protein grain legumes
2. Poor man meat in developing countries.
3. It has higher protein than cereals.
4. It can increase soil fertility through nitrogen fixation.
5. Cereal crops are grain crops and they are rich source of carbohydrates.
6. Good source of animal and poultry feed.
parameter Gram or
Lentil or
or green
Pigeon pear
or arhar
Local name channa masoor Green gram Arhar
Lens culinaris Vigna
Pollination self self self Cross
Photoperiod Long long self Cross
Root system Tap root
Tap root
Tap root
Tap root
Season rabi rabi Kharif or
Kharif or
resistant to
Not resistant
to heat and
adaptation Semi arid semiarid Tropical or
or tropical
Soil and
Sandy to
sandy clay
Loam to clay
Sandy loam
No of
1-3 2-3 3-4 1-3
No of
1-2 1-2 2-3
fertilizers 15.50.50 25.60.60 20.60.60 25.50.00
Introduction to Agriculture Notes prepared by: Aqleem Abbas
No nodule
Time of
Sept to
Oct to
June to july
broadcast broadcast broadcast Broad cast
Seed rate 50-60 25-30 25-30 30-40
weeding 1-2 1-2 2-3 2
irrigation 1-2 No irrigation 2-3 6-7
Insect or pest Cater piller,
Aphid, weevils aphid Pod borer
disease Blight, root
mildew, rust,
Leaf spot or
mosaic virus
harvesting March-april March-april Sept-oct Oct-nov
storage 10 % <10 % <10 % <10%
yield 700-800 kg
per hectar
600-700 kg
per hectare
800-900 kg
per hectare
per hectare
cultivar Punjab 91,
noor 91,
karak 7
89, precoz
98, NM 19-
Sugar cane and sugar beet
By product (leaves, top) are used for the preparation of paper and also use as feed for animals. By product
(molasses) are used as alcohol and remaining part of molasses called bagasses. Most of sugarcane
cultivars are male sterile and therefore they donot change into reproductive stage. But there are two areas
jaban (dargai) and karachi where sugarcane reach to its reproductive stage. Sugar beet reprodcuting stage
is called bolting stage which occur in second year which is undesirable because sugar content decreases.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
parameters Sugar cane Sugar beet
Local name ghanna Chukander
Scientific name Sacchrum officinarum Beta vulgaris
Mode of pollination cross Cross
Season Spring or autumn Rabi or winter
Roots fibrous Tap root
Adaptation Tropical only irrigated and
semi arid
Temperate or soil
Climate Heavy soil clay to clay loam Loam, clay to silt
Cultural practices
Land preparation
No of plowing 6-8 4-5
No of planking 1-2 1-2
NPK 175.80.60
125.80.40 FOR
IRRIGATION 12-15 6-8
30-40 TONS PER
92,93, CP 77/400
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Potato, edible starchy tuber. It is produced by certain plants of a genus of the nightshade family, especially the common white
potato. The name is also applied to the plants.
The white-potato tuber is a food staple in most countries of the temperate regions of the world.
The plant is grown as an annual herb. The stem attains a length of up to almost 1 m (almost 3 ft), erect or prostrate, with pointed
leaves and white to purple flowers. The fruit is a many-seeded berry about the size of a cherry. Like the stems and the foliage, the
fruit contains significant amounts of solanin, a poisonous alkaloid characteristic of the genus. The plant, native to the Peruvian
Andes, was brought to Europe in the 16th century by Spanish explorers. The cultivation of the potato spread rapidly, especially in
the temperate regions, and early in the 18th century the plant was introduced into North America. The earliest authentic record of
its cultivation there was dated 1719, at Londonderry, New Hampshire. In ordinary cultivation, propagation is accomplished by
planting the tuber or a section of the tuber containing an eye, which is an undeveloped bud. New varieties are developed from
seed produced after controlled pollination. Improved varieties may be propagated rapidly by using cuttings from the sprouts.
Rich, sandy loams are most suitable for producing the light, mealy types; heavy, moist soils produce the firm type preferred.
Freshly dug potatoes contain 78 percent water, 18 percent starch, 2.2 percent protein, 1 percent ash, and 0.1 percent fat. About 75
percent of the dry weight is carbohydrate. The potato is an important source of starch for the manufacture of adhesives and
The most important disease of the potato is late blight, caused by a fungus that rots leaves, stems, and tubers. The early blight,
caused by a different fungus, is not so destructive but causes lesions that permit entry of the various forms of bacterial rot.
Several forms of mosaic disease and leaf curl are caused by infection with viruses.
The Colorado potato beetle is the most destructive of the insect pests; others include the potato leafhopper, the potato flea beetle,
and species of aphids and psyllids. See also Sweet Potato.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Scientific classification: Potatoes are produced by plants of the genus Solanum, of the family Solanaceae. The common white
potato is classified as Solanum
tuberosum .
Compost, partially decomposed organic material used in gardening to improve soil and enhance plant growth. Compost
improves the movement of water, dissolved nutrients, and oxygen through the soil, making it easier for plant roots to absorb
these vital substances.
A versatile material, compost benefits virtually any soil type.
Clay soil, for example, has tiny, tightly packed particles that hamper the flow of water, nutrients, and oxygen. Compost
reconfigures the clay into larger, more loosely packed particles. The larger spaces between the particles improve the flow of
water, oxygen, and nutrients to roots. In addition, the roots are able to penetrate deeper into the soil and contact more nutrients.
Compost also improves sandy soil, where the large spaces between loosely packed particles enable water and its dissolved
nutrients to drain too quickly for optimum root absorption. Compost soaks up and holds these substances so that the roots have
more time to absorb them. Compost also adds small amounts of zinc, copper, boron, and other vital nutrients to soils.
Compost is made by harnessing the natural decomposition process carried out by certain species of microorganisms. These
microorganisms, primarily bacteria and fungi, live in intimate association with their food supply—on the surface of dead plants,
in soil, or on or in animal waste. By breaking down these materials with their digestive enzymes, the tiny creatures release and
absorb the nutrients within. For home gardeners, making compost is simply a matter of collecting food for microorganisms in one
place and letting them go to work.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
A broad range of organic matter, including manure from plant-eating animals, grass clippings, and dead leaves or garden plants,
provides a veritable feast for microorganisms. For optimal decomposition, the combined starting materials should have an
appropriate carbon to nitrogen ratio, preferably 30 parts carbon to 1 part nitrogen. Leaves, straw, and paper, called brown
materials, have a high carbon to nitrogen ratio, about 300 to 1, while grass clippings, kitchen scraps, and manure, called green
materials, have a low carbon to nitrogen ratio, about 15 to 1. For the best mix, green materials should be added in abundance;
brown materials should be used more sparingly. Materials that should not be used to make compost include manure from meat-
eating animals, because it may contain disease-causing organisms that can harm humans who eat plants grown in the compost.
Meat should be avoided since it may attract rodents. Fatty foods such as cheese also should not be added to the compost pile, as
they are hard for most microorganisms to digest.
The starting materials are heaped into a pile—in a home garden, the pile is typically about a meter high and a meter wide (about
three feet high and three feet wide); on farms, composting is done on a larger scale. The pile may sit loose on the ground or it
may be enclosed using a variety of materials, including wire fencing, wood boards, cinder blocks, or widely stacked bricks.
A variety of techniques may be used to increase the rate of compost decomposition. One technique is to cut the starting materials
into 10- to 15-cm (4- to 6-in) pieces to increase the surface area on which the microorganisms act. Increased surface area
accelerates decomposition, much like a large ice chunk melts faster if broken up into small pieces. The microorganisms in the
compost pile also thrive when oxygen and moisture are present. Fluffing the compost pile every week or so with a pitchfork or
other tool introduces oxygen into the pile, and sprinkling water on the pile when it dries out provides the necessary moisture.
In a well-managed compost pile, the microorganisms eat and reproduce rapidly, and heat is released as a byproduct of their
intense biochemical activity. The heat in the pile kills most plant diseases and weed seeds that may have been present on the
starting materials. The increased heat may also kill the microorganisms doing the decomposing as well, especially those at the
center of the pile where temperatures may climb to 90° C (200° F). Mixing the materials well about once a week prevents lethal
temperature increases by distributing the heat evenly throughout the pile.
The time it takes microorganisms to decompose the starting materials in compost varies. Factors include the size of the pile, the
techniques used to manage the pile, and the nature of the starting materials—green materials decompose readily, while brown
materials take longer to break down. In an actively managed compost pile, microorganisms use up their food supply and become
less active after about six weeks. Then the pile slowly cools, signaling the near-final stages of decomposition. If the materials in a
compost pile are relatively large, if the pile is not kept moist, and if oxygen is not introduced, microorganism activity is slow and
the pile does not heat up. Depending upon the climate, it may take months or years for decomposition to occur.
No matter how long decomposition takes, when in its final stage, the compost pile is about half its original size and resembles
dark soil. The material in the pile is now called humus—although the terms humus and compost sometimes are used
interchangeably. Humus is the highly beneficial material that is added to the garden soil. Once in or on the soil, it continues to
decompose at a very slow rate, releasing ammonia, carbon dioxide, and salts of calcium, phosphorus, and other elements that are
beneficial for plant growth.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Humus can be added to the soil at any time of year. It can be worked into the soil, where its benefits take effect most rapidly, or it
can be left on the soil surface. Humus can be used year after year, and there is never danger of adding too much, since this
remarkable substance only enhances soil and encourages plants to thrive.
Cities compost on a large scale to reduce yard waste so that it does not take up space in landfills. Industries compost hazardous
materials because the activities of the microorganisms help break down toxic substances into less-harmful or harmless materials.
Many municipalities provide information on composting as part of their programs to reduce the amount of solid waste entering
their landfills. County or regional offices of the state Cooperative Extension Service also have information on composting.
Organic Farming
Organic Farming, system of agriculture that excludes the use of synthetic pesticides, growth hormones, antibiotics, genetically
modified seeds and animal breeds, and irradiation. Organic farmers instead rely on ecosystem management, including the use of
pesticides and fertilizers derived from plants, animal wastes, and minerals. They incorporate biological methods, such as the use
of one organism to suppress another, to help control pests. The methods used in organic farming seek to increase soil fertility,
balance insect populations, and reduce air, soil, and water pollution.
In the United States, organic farming is a rapidly growing sector of agriculture. In 2006 organic food sales reached $16.7 billion,
up from $7 billion in 2001. Exports of organic food products are also growing, particularly to Japan and Europe.
Organic farming techniques
Organic farming combines a variety of methods to maintain the health of soil, prevent soil erosion, and control pests with
minimal or no use of synthetic pesticides. Conventional farmers also use some of these methods, but to a lesser degree.
Soil preservation in organic farming
Fertilizers are used to provide the minerals lacking in some soils, and to replace the minerals removed from the soil by crops as
they grow. Many conventional farmers rely on concentrated chemical fertilizers that are rapidly absorbed by plants. These
fertilizers produce quick growth but may kill important soil organisms, such as earthworms and beneficial bacteria. Organic
farmers use manure, compost (a mixture of decaying organic matter that is rich in beneficial soil microorganisms), and other
natural materials to nourish soil organisms, which in turn make minerals available to plants.
Organic farmers are more likely than conventional farmers to rotate crops, a technique that replenishes soil nutrients without the
use of synthetic fertilizers. In crop rotation, a field is used for one to several years to grow one type of crop, such as corn or
wheat, followed by a season in which a legume such as alfalfa or soybean is planted. Legume roots harbor beneficial bacteria that
Introduction to Agriculture Notes prepared by: Aqleem Abbas
incorporate nitrogen from the air into the soil (see Nitrogen Fixation), enriching the soil and reducing the need for nitrogen-
containing fertilizers. Crop rotation also conserves nutrients. For example, the roots of the first crop may be near the surface and
the second crop’s roots may be deeper, so that nutrients are drawn from different depths in the soil.
Soil held in place by plant roots is less likely to blow or wash away, or erode, than bare soil. Organic farmers minimize soil
erosion with cover crops—short-lived plants, often grasses or legumes—that protect the soil between the harvesting of one crop
and the planting of the next. Many organic farmers also conserve soil by practicing no-till or low-till farming, avoiding the use of
plows to turn the soil, or using implements that only slice or slightly turn the soil. They may also leave the unharvested portion of
a crop in the field to cover the soil, preventing soil erosion from wind or rain.
Pest management in organic farming
Conventional farms rely on an array of synthetic pesticides to kill weeds, disease-causing fungi, and harmful insects. These
pesticides are manufactured by chemically processing petroleum, natural gas, ammonia, and a number of other raw materials.
They include active and inactive ingredients, both of which can be highly toxic and long lasting. Organic farmers typically use
pesticides primarily derived from chemically unaltered plant, animal, or mineral substances in which the active toxic ingredient
breaks down rapidly to become nontoxic after being applied to the crop. Pyrethrum (a substance extracted from the
chrysanthemum), a variety of soaps, and oil from the neem tree are among the insecticides used by organic farmers. Bordeaux
mix, a combination of calcium carbonate and copper, is used by organic farmers to control disease-causing fungi.
In addition to using natural pesticides, organic farmers control pests by planting different crops in wide, alternating bands, a
technique called intercropping. This approach interrupts the movement of disease-causing organisms through a field, since many
insects and fungi feed on just one type of crop. Organic farmers also reduce insect damage by spraying crops with bacteria that
kill larvae (immature insects) and planting crops that attract ladybugs, lacewings, and other beneficial insects that prey on
unwanted insects.
Organic farmers use many methods for weed control. Mulching involves covering the soil around crops with straw or other
materials that smother weeds. Cover crops can be planted in the fall and turned under in a few months; they help control weeds
by competing with them—an oat crop, for example, grows faster than weeds and deprives them of the nutrients they need to
produce seeds. Other types of cover crops, such as cereal rye, release substances from their roots that inhibit weed seed
germination. Organic farmers sometimes use a variety of tractor-drawn equipment to uproot weeds that emerge with crops.
Organic farming is sometimes referred to as sustainable agriculture, although the two concepts have subtle but significant
differences. Sustainable agriculture seeks to improve the entire food and agricultural system by balancing production and
consumption. For example, a farmer practicing sustainable agriculture may use the manure from the animals to fertilize the fields
of grain that are grown to feed the animals. Eliminating the purchase of fertilizer reduces the cost of growing grain, and growing
grain for animal feed rather than buying it reduces the cost of raising livestock.
Sustainable agriculture also addresses the environmental, economic, and social issues related to agricultural systems. It attempts
to ensure that arable land is protected so that current and future generations will be able to farm it successfully; many involved in
sustainable agriculture also seek to preserve the vitality of family-owned farms and rural communities. A sustainable farm may
not be organic, and an organic farm may not be sustainable, although they may use similar techniques.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
For consumers, the most obvious benefit of organic farming is health-related. Studies show that organically grown food contains
higher levels of essential minerals than conventionally grown food. In addition, organic food is free from genetically modified
organisms (GMOs), hormones, and antibiotics, and has little or no pesticide residue.
Longer-term benefits of organic farming include the preservation and enhancement of soil, increasing the likelihood that it will
continue to produce quality food for future generations. Organic farming encourages healthy populations of beneficial insects that
keep destructive insects under control. It also helps preserve aquatic life and clean water by minimizing the flow of toxic
pesticides into streams, rivers, and lakes.
Critics of organic farming argue that the method is less profitable, requiring more labor and management skill than a
conventional farm. Savings on pesticides, fertilizers, and fuels, however, usually offset the cost of the extra labor. And the
environmental benefits of organic farming represent long-term savings, not just for the organic farmer, but also for future
Prior to the invention of synthetic fertilizers and pesticides, all farming was “organic” by definition. In the modern age, one of the
first proponents of organic farming was the British agriculturalist Sir Albert Howard, who, in his 1940 book An Agricultural
Testament, advocated farming without synthetic fertilizers and pesticides. British agriculturist Lady Eve Balfour was also
involved in the 20th-century organic farming movement. Her 30-year research farm, the Haughley Experiment, was the site of
numerous experiments comparing organic and conventional farming. Balfour’s book, The Living Soil (1943), corroborated
Howard’s studies and documented the importance of healthy soil for farming. The work of Howard and Balfour inspired
American researcher and publisher J. I. Rodale to found Organic Farming and Gardening magazine in 1942 (now called Organic
Gardening), which educates the public about organic techniques. Rodale also established the nonprofit Soil and Health
Foundation research center (now called the Rodale Institute).
Rachel Carson, a marine biologist with the United States Fish and Wildlife Service, added momentum to the organic farming
movement with her book Silent Spring (1962), which chronicles the harmful effects of pesticides on wildlife. Also in the United
States, Helen and Scott Nearing pioneered in organic farming. Their book Living the Good Life (1954) and their numerous other
publications promoted organic farming and helped inspire the back-to-the-land movement of the 1960s and 1970s.
Hydroponics, term applied to cultivation of plants in nutrient solutions without use of soil. Soilless growing of cultivated plants
began in the 1930s as an outgrowth of the culture techniques used by plant physiologists in plant nutrition experiments. More
recent successful methods of soilless growth differ in particulars but have two common features: (1) nutrients are supplied in
liquid solutions; and (2) plants are supported by porous material, such as peat, sand, gravel, or glass wool, that acts as a “wick” in
relaying the nutrient solution from its source to the roots.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Through photosynthesis, green plants manufacture their own organic food, using carbon dioxide and oxygen as raw materials.
The nutrients usually supplied to plants by soil are almost entirely mineral salts. Plant physiologists have discovered that plants
require carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, magnesium, sulfur, calcium, iron, manganese, boron, zinc,
copper, and probably molybdenum. Carbon, hydrogen, and oxygen are obtained in large quantities from water and air, but the
remaining elements are ordinarily supplied as salts by the soil. The relative amount of each of these elements required for normal
growth is different in each plant, but all plants require relatively large proportions of nitrogen, phosphorus, potassium,
magnesium, sulfur, and calcium. Iron, manganese, boron, zinc, copper, and molybdenum are supplied in minute quantities, and
are called micronutrients or trace elements. The specific salts used to supply these elements may be varied at the discretion of the
grower; a typical solution of primary minerals is composed of distilled water containing potassium nitrate, KNO
, calcium nitrate,
, potassium acid phosphate, KH
, and magnesium sulfate, MgSO
In solution, the salts dissociate into ions;
potassium nitrate, for example, is available to plants as the ions K
and NO
. A solution of micronutrient salts is added to the
solution of primary elements to complete the nutrient solution. A small amount of fungicide is usually added to prevent the
growth of mold.
Hydroponic culture method
Several culture techniques are used. The most practical commercial method is subirrigation, in which plants are grown in trays
filled with gravel, cinders, or other coarse materials, and periodically flooded with nutrient solution. The solution is allowed to
drain off after each flooding and may be reused as long as sufficient minerals remain in it. The water-culture method is used
widely for botanical experimentation. A common type of water culture consists of glazed porcelain jars filled with solution; the
plants are placed in beds of glass wool or similar material that are supported at the surface of the solution. Roots of the plants
penetrate the beds and remain in the solution. The least exact method, commonly called the slop method, is the easiest to operate.
Coarse, clean sand is used in place of soil, and nutrient solution is poured on the sand in approximately equal amounts at regular
intervals. A refinement of this practice is the drip method, in which a steady, slow feed of nutrient is maintained. Excess nutrient
solution is allowed to drain off in both slop and drip methods.
Hydroponic culture methods are being used successfully to produce plants out of season in greenhouses and to produce plants in
areas where either the soil or the climate is not suitable for the crop grown. During World War II, for example, several U.S. Army
units successfully produced vegetables hydroponically at various over-seas bases. In the 1960s hydroponic farming developed on
a commercial scale in the arid regions of the United States, particularly in Arizona, where research was also undertaken at state
universities. In other arid regions, such as the Persian Gulf and the Arab oil-producing states, hydroponic farming of tomatoes
and cucumbers is under way; these countries are also researching an additional group of crops that may be grown by this method,
as they have limited arable land.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Water Cycle
Water Cycle or Hydrologic Cycle, series of movements of water above, on, and below the surface of the earth. The water cycle
consists of four distinct stages: storage, evaporation, precipitation, and runoff. Water may be stored temporarily in the ground; in
oceans, lakes, and rivers; and in ice caps and glaciers. It evaporates from the earth’s surface, condenses in clouds, falls back to
the earth as precipitation (rain or snow), and eventually either runs into the seas or reevaporates into the atmosphere. Almost all
the water on the earth has passed through the water cycle countless times. Very little water has been created or lost over the past
billion years.
Enormous volumes of water are involved in the water cycle. There are about 1.4 billion cu km (about 340 million cu mi) of water
on the earth, enough to cover the United States with water 147 km (92 mi) deep. Slightly more than 97 percent of this amount is
ocean water and is therefore salty. However, because the water that evaporates from the ocean is almost free of salt, the rain and
snow that fall on the earth are relatively fresh. Fresh water is stored in glaciers, lakes, and rivers. It is also stored as groundwater
in the soil and rocks. There are about 36 million cu km (about 8.6 million cu mi) of fresh water on the earth.
The atmosphere holds about 12,000 cu km (about 2,900 cu mi) of water at any time, while all the world’s rivers and freshwater
lakes hold about 120,000 cu km (about 29,000 cu mi). The world’s two main reservoirs of fresh water are the great polar ice caps,
which contain about 28 million cu km (about 6.7 million cu mi), and the ground, which contains about 8 million cu km (about 2
million cu mi).
Almost all of the world’s fresh ice is found in the ice caps of Antarctica and Greenland. These ice caps cover more than 17
million sq km (more than 6.6 million sq mi) of land to an average depth of more than 1.5 km (more than 0.93 mi). Most other
glaciers, formed in mountain valleys at high latitudes, are tiny compared to the ice caps. If all of the ice in the ice caps and other
glaciers melted, it would raise the sea level by about 80 m (about 260 ft).
The amount of water stored as ice on the land varies with climate. At the peak of the last ice age, about 22,000 years ago, an
additional 20 million sq km (8 million sq mi) of land—including almost all of Canada, the northern fringe of the United States,
northern Europe, and large tracts in Siberia—were covered with ice about 1.5 km (about 0.93 mi) thick. Because this water came
from the oceans, sea level was about 120 m (about 390 ft) lower than it is today. Most water in the ice caps remains frozen for
centuries and is not readily accessible.
Most groundwater is more accessible and supplies much of people’s water needs in many regions of the earth. Permafrost,
ground that is always frozen, forms an impermeable barrier to the flow of groundwater. Permafrost occurs in places such as
northern Canada and Siberia where the annual average temperature is below 0° C (below 32° F).
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Almost all groundwater fills the tiny pores and cracks in the soil and rocks. Very little is stored in subterranean caverns. Near the
earth’s surface, most soils and sedimentary rocks are so porous that water can occupy from 20 to 40 percent of their volume. As
depth increases, the pores and open spaces in the rocks are squeezed shut. As a result, almost all groundwater is found in the top
8 to 16 km (5 to 10 mi) of the earth. Water below this depth is chemically bound in the rocks and minerals and is not readily
available, but it can be released as a result of geologic processes such as volcanic eruptions (see volcano).
Evaporation is the process by which liquid water changes to water vapor and enters the atmosphere as a gas. Evaporation of ice is
called sublimation. Evaporation from the leaf pores, or stomata, of plants is called transpiration. Every day about 1,200 cu km
(about 290 cu mi) of water evaporates from the ocean, land, plants, and ice caps, while an equal amount of precipitation falls
back on the earth. If evaporation did not replenish the water lost by precipitation, the atmosphere would dry out in ten days.
The evaporation rate increases with temperature, sunlight intensity, wind speed, plant cover, and ground moisture, and it
decreases as the humidity of the air increases. The evaporation rate on the earth varies from almost zero on the polar ice caps to
as much as 4 m (as much as 13 ft) per year over the Gulf Stream. The average is about 1 m (about 3.3 ft) per year. At this rate,
evaporation would lower sea level about 1 m per year if the water were not replenished by precipitation and runoff.
Precipitation occurs when water vapor in the atmosphere condenses into clouds and falls to the earth. Precipitation can take a
variety of forms, including rain, snow, ice pellets, and hail. About 300 cu km (about 70 cu mi) of precipitation falls on the land
each day. Almost two-thirds of this precipitation reevaporates into the atmosphere, while the rest flows down rivers to the oceans.
Individual storms can produce enormous amounts of precipitation. For example, an average winter low-pressure system drops
about 100 cu km (about 24 cu mi) of water on the earth during its lifetime of several days, and a severe thunderstorm can drop
0.1 cu km (0.02 cu mi) of water in a few hours over a small area.
Water that flows down streams and rivers is called surface runoff. Every day about 100 cu km (about 24 cu mi) of water flows
into the seas from the world’s rivers. The Amazon River, the world’s largest river, provides about 15 percent of this water.
Runoff is not constant. It decreases during periods of drought or dry seasons and increases during rainy seasons, storms, and
periods of rapid melting of snow and ice.
Water reaches rivers in the form of either overland flow or groundwater flow and then flows downstream. Overland flow occurs
during and shortly after intense rainstorms or periods of rapid melting of snow and ice. It can raise river levels rapidly and
produce floods. In severe floods, river levels can rise more than 10 m (more than 33 ft) and inundate large areas. Groundwater
flow runs through rocks and soil. Precipitation and meltwater percolate into the ground and reach a level, known as the water
table, at which all of the spaces in the rocks are filled with water. Groundwater flows from areas where the water table is higher
to areas where it is lower. The speed of flow averages less than 1 m (less than 3.3 ft) a day. When groundwater reaches streams, it
supplies a base flow that changes little from day to day and can persist for many days or weeks without rain or meltwater. During
periods of sustained drought, however, the water table can fall so low that streams and wells dry out.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Effects on human activity
Human beings have been altering the water cycle for thousands of years. Irrigation channels are constructed to bring water to dry
land. Wells are dug to obtain water from the ground. Excessive pumping from wells has drastically lowered the water table,
depleting some ancient water supplies irreversibly and causing the intrusion of salt water into groundwater in densely populated
low-lying coastal regions. Levees are built to control the course of rivers, and dams are built to render rivers navigable, store
water, and provide electrical power. Evaporation of water behind dams is a serious source of water loss. Increasing urbanization
has led to more severe flooding because rainwater reaches streams more rapidly and in greater quantity from areas where the
ground has been paved.
As human population continues to grow, effective use and management of the planet’s water resources have become essential.
Careful management of waterworks has alleviated many problems, but limits to the water supply place limits on the sustainable
population of an area and can play an important part in the politics of some regions, as in the Middle East.
Nitrogen Cycle,
natural cyclic process in the course of which atmospheric nitrogen enters the soil and becomes
part of living organisms, before returning to the atmosphere. Nitrogen, an essential part of the
amino acids, is a basic element of life. It also makes up 78 percent of the Earth’s atmosphere, but
gaseous nitrogen must be converted to a chemically usable form before it can be used by living
organisms. This is accomplished through the nitrogen cycle, in which gaseous nitrogen is
converted to ammonia or nitrates. The high energies provided by lightning and cosmic radiation
serve to combine atmospheric nitrogen and oxygen into nitrates, which are carried to the Earth’s
surface in precipitation. Biological fixation (see Nitrogen Fixation), which accounts for the bulk
of the nitrogen-conversion process, is accomplished by free-living, nitrogen-fixing bacteria;
symbiotic bacteria living on the roots of plants (mostly legumes and alders); cyanobacteria
(formerly known as blue-green algae); archaebacteria (also known as archaea) in deep-sea
hydrothermal vents and other geothermal environments; certain lichens; and epiphytes in tropical
Nitrogen “fixed” as ammonia and nitrates is taken up directly by plants and incorporated in
their tissues as plant proteins. The nitrogen then passes through the food chain from plants to
herbivores to carnivores. When plants and animals die, the nitrogenous compounds are broken
down by decomposing into ammonia, a process called ammonification. Some of this ammonia is
taken up by plants; the rest is dissolved in water or held in the soil, where microorganisms
convert it into nitrates and nitrites in a process called nitrification. Nitrates may be stored in
decomposing humus or leached from the soil and carried to streams and lakes. They may also be
converted to free nitrogen through denitrification and returned to the atmosphere.
In natural systems, nitrogen lost by denitrification, leaching, erosion, and similar processes is
replaced by fixation and other nitrogen sources. Human intrusion in the nitrogen cycle, however,
can result in less nitrogen being cycled, or in an overload of the system. For example, the
cultivation of croplands, harvesting of crops, and cutting of forests all have caused a steady
Introduction to Agriculture Notes prepared by: Aqleem Abbas
decline of nitrogen in the soil. (Some of the losses on agricultural lands are replaced only by
applying energy-expensive nitrogenous fertilizers manufactured by artificial fixation.) On the
other hand, the leaching of nitrogen from overfertilized croplands, cutover forestland, and animal
wastes and sewage has added too much nitrogen to aquatic ecosystems, resulting in reduced
water quality and the stimulation of excessive algal growth. In addition, nitrogen dioxide poured
into the atmosphere from automobile exhausts and power plants breaks down to form ozone and
reacts with other atmospheric pollutants to form photochemical smog.
Complete flower
Those in which floral part are present e.g. tobacco, brassica, cotton
Incomplete flower
Those in which at least one floral part is missing e.g. wheat,rice
Permanent flower
In which both male and female parts are present e.g. wheat, rice, flower
Imperfect flower
Such a flower which has either male part or female part e.g. maize, date palm.
Hermaphrodite or perfect flower
Presence of male and female part on same flower is called perfect flower.
Variations in a population is the basis for selection. Such variations can be hereditary or
eniornmental. Without hereditary variations any adverse change in the environment may finish a
pecies in its natural habitat. Hereditary variations are important for breeding of plants they
results in permanent hereditable changes in the genotype. Such variation can occur in plants due
to many factors.
Chromosomal aberration
That donot involved changes in number of chromosomes but results from changes in number and
sequences of gene of chromosomes.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
Sudden new variations or changes that is inherited. It is variously used to include individual gene
changes and chromosome changes.
Any organism with more than two sets of basic or monoploid (haploid) no of chromosomes. It is
exact multiple of monoploid.
For example triploid three sets of chromosomes
Tetraploid, and penta ploid. 23,46,69 etc.
Aneuploid or heteroploid
It is not an exact multiple of monoploid.
Hyper…….23 multiple is 46 but here 47 forms.
Hypo………23 multiple is 46 but here 45 forms.
The observed new combination of characters different from those shown or exhibite by parents.
These process occurs in nature but a plant breeder strive to increase frequency and attempts to
induce the desired changes. The new genotype serves as the basis for selection and further
breeding. The knowledge and control of these basic processes has revolutionized plant breeding
and man has been able to successfully create new and useful varieties. Origin of wheat is good
example. These crops originated in nature is a result of complex hybridizations and polyploidy
over a no of years. But man has been able to resynthesize this plants in only a few years by
controlled crosses and induce doubling of chromosome complement of hybrids. Many species of
brassica and solanum has been resynthesize. Generally autopolyploid are more vigorous than
corresponding diploid and tend to have large leaves, fruits, flowers, seeds etc.
The knowledge that radiation can induce mutations are available and many chemicals also
known which can induce mutations. Triple gene dwarf wheat variety is good example of induce
Reproduction is a mean of increasing population as well as maintaining continuity of species.
Before initiating a breeding program a plant breeder should have a good knowledge of plant
reproductive system.
Reproduction in plants can occur by three main ways.
a. Sexual reproduction
b. Asexual reproduction e.g. apomixes
c. Vegetative reproduction or cloning propagation.
Introduction to Agriculture Notes prepared by: Aqleem Abbas
INDIA Hyderabad.
SYRIA Aleppo province
National agricultural organizations
This research hasn't been cited in any other publications.
    • International Centre
    • Wheat
    • Maize
    • Improvement
  • ICARDA) SYRIA Aleppo province National agricultural organizations 1. ARID ZONE RESARCH INSTITUTE (AZRI) BALOUCHSITAN Quetta 2
    • International Crop
    • Research
    • Areas