Evolution of the plow over 10,000 years and the rationale for no-till farming

Abstract

Agriculture and the plow originated 10–13 millennia ago in the Fertile Crescent of the Near East, mostly along the Tigris, Euphrates, Nile, Indus and Yangtze River valleys, and were introduced into Greece and southeastern Europe ∼8000 years ago. The wooden plow, called an ard, evolved into the “Roman plow”, with an iron plowshare, described by Virgil around 1 ad and was used in Europe until the fifth century. It further evolved into a soil inverting plow during the 8th to 10th century. In the U.S., a moldboard plow was designed by Thomas Jefferson in 1784, patented by Charles Newfold in 1796, and marketed in the 1830s as a cast iron plow by a blacksmith named John Deere. Use of the plow expanded rapidly with the introduction of the “steam horse” in 1910 that led to widespread severe soil erosion and environmental degradation culminating in the Dust Bowl of the 1930s. A transition from moldboard plow to various forms of conservation tillage began with the development of 2,4-D after World War II. No-till is presently practiced on about 95 million hectares globally. No-till technologies are very effective in minimizing soil and crop residue disturbance, controlling soil evaporation, minimizing erosion losses, sequestering C in soil and reducing energy needs. However, no-till is effective only with the use of crop residue as mulch, which has numerous competing uses. No-till farming can reduce yield in poorly drained, clayey soils when springtime is cold and wet. Soil-specific research is needed to enhance applicability of no-till farming by alleviating biophysical, economic, social and cultural constraints. There is a strong need to enhance sustainability of production systems while improving the environmental quality.

Full text

Editorial
Evolution of the plow over 10,000 years and the
rationale for no-till farming
Abstract
Agriculture and the plow originated 10–13 millennia ago in the Fertile Crescent of the Near East, mostly along the Tigris,
Euphrates, Nile, Indus and Yangtze River valleys, and were introduced into Greece and southeastern Europe 8000 years ago. The
wooden plow, called an ard, evolved into the ‘‘Roman plow’’, with an iron plowshare, described by Virgil around 1 AD and was used
in Europe until the fifth century. It further evolved into a soil inverting plow during the 8th to 10th century. In the U.S., a moldboard
plow was designed by Thomas Jefferson in 1784, patented by Charles Newfold in 1796, and marketed in the 1830s as a cast iron
plow by a blacksmith named John Deere. Use of the plow expanded rapidly with the introduction of the ‘‘steam horse’’ in 1910 that
led to widespread severe soil erosion and environmental degradation culminating in the Dust Bowl of the 1930s. A transition from
moldboard plow to various forms of conservation tillage began with the development of 2,4-D after World War II. No-till is
presently practiced on about 95 million hectares globally. No-till technologies are very effective in minimizing soil and crop residue
disturbance, controlling soil evaporation, minimizing erosion losses, sequestering C in soil and reducing energy needs. However,
no-till is effective only with the use of crop residue as mulch, which has numerous competing uses. No-till farming can reduce yield
in poorly drained, clayey soils when springtime is cold and wet. Soil-specific research is needed to enhance applicability of no-till
farming by alleviating biophysical, economic, social and cultural constraints. There is a strong need to enhance sustainability of
production systems while improving the environmental quality.
#2006 Elsevier B.V. All rights reserved.
Keywords: Conservation tillage; No-till farming; Tillage intensity; Evolution of agriculture; Soil erosion; Dust bowl; Desertification; Tillage
implements
1. Introduction
The beginning of civilization depended on agriculture
for food production—so does civilization’s future. At the
end of the last glaciation, some humans began to take
advantage of their natural landscapes in ways that their
ancestors could not have imagined. The early human
hunters and gatherers defined the human civilization,
about 10–13 millennia agowhen settled agriculture began
(Cavalli-Sforza and Cavalli-Sforza, 1995; Manning,
2004). Indeed, it followed the popular saying ‘‘Where
farming starts, other arts follow’’ (Jack, 1946). The
agricultural revolution occurred across many genera-
tions, culminating into the Green Revolution in the
second half of the 20th century. The agricultural
revolutioninvolved use of genetically improved varieties,
supplemental irrigation where needed, soil fertility
enhancing organic amendments and inorganic fertilizers,
and plow-based seedbed preparation. The rise of urban
societies centered in impressively wealthy cities was
entirely based on the food surpluses of plow-based
agriculture. By the time the industrial revolution rolled
around in the 1700s, the technologies developed
throughout the agricultural revolution enabled the human
population to soar from a mere 4 million around 8000 BC
to nearly 400 million. Moreover, average settlement size
grew from a mere 200–300 people to cities with over a
million people. In a few thousand years, early civiliza-
tions tackled the first environmental constraint limiting
their ability to feed, clothe and shelter themselves, and in
the process transformed their daily lives. The agricultural
revolution transformed the landscape, ecosystems,
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Soil & Tillage Research 93 (2007) 1–12
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vegetation, soils and water resources. These transforma-
tions had far reaching and often irreversible impact on the
cycles of water and other elements (e.g., C, N, P). Human
appropriation of ecosystem services and Earth’s natural
resources have been unprecedented since the agricultural
revolution.
Over the millennia, plowing became synonymous
with tillage and seedbed preparation. Yet, there is a need
to revisit the scientific basis and rationale for plowing as
a tool for seedbed preparation. We discuss the evolution
of plow tillage from an historical perspective. The
specific objective of this review is to present a historical
perspective on the development of civilization and its
dependence on the plow-based agriculture. The soil and
environmental impacts of intensive tillage are discussed
and the rationale for adopting less intensive forms of
tillage with more emphasis on minimum soil dis-
turbance, continuous crop residue cover, and diverse
crop rotations are described.
2. Historical evolution of plow tillage
Settled agriculture originated in the Fertile Crescent of
the Near East, mostly along the Tigris, Euphrates, Nile,
Indus and Yangtze River valleys by the so-called ‘‘hydric
civilizations.’’ Some of the earliest cultivated crops
included emmer (broadly, tetraploid wheat), einkorn (the
most primitive wheat), barley, flax, chickpea, lentil, pea,
and bitter vetch. Farming was introduced into Greece and
southeast Europe from the Near East more than 8000
years ago. About 10 millennia ago, Sumerian and other
civilizations developed simple tools to place and cover
seed in the soil. Soil preparation through tillage has
always been an important component of traditional
agriculture. Tillage has been defined as the mechanical
manipulation of the soil and plant residues to prepare a
seedbed where crop seeds are planted to produce grain for
human and animal consumption (Reicosky and Allmaras,
2003). Tillage involves seedbed preparation and post-
emergent cultivation for weed control.
The on-set of settled agriculture led to the
development of ancient civilizations in the fertile
alluvial plains of Mesopotamia, the Nile Valley and
other rivers. Agriculture started in these alluvial plains
in an arid climate where farmers began to grow food
crops by irrigation in quantities greater than their own
needs and released their fellow humans for a division of
labor that gave rise to the so-called civilization.
Importance of agriculture and the need to maintain
and enhance soil fertility were written by Spanish
Moores during the 12th century (Aboul-Khayr et al.,
1946). Lowdermilk (1953) presented a story of
precarious agriculture by people who lived and grew
up under the threat of raids and invasions from
marauders of the grasslands in the desert. In Mesopo-
tamia, agriculture was practiced in the very dry climate
with canal irrigation using muddy water.
A wide variety of tillage tools were originally
designed, ranging from a simple digging stick to a
paddle-shaped spade or hoe that could be pulled by
humans or animals (Fig. 1). A wooden plow, called an
‘‘ard,’’ was probably developed in Mesopotamia about
4000 to 6000 BC. The ‘‘Triptolemos ard’’ was named
after the Greek God and hero about 4000 BC (Glob,
1951). Historical documents and archaeological evi-
dence illustrate the ‘‘mystique’’ of tillage implements
that were thought to ‘‘nourish the earth’’ and to ‘‘break
the drought.’’ Over time, the ard evolved into the well-
known ‘‘Roman plow’’ described by Virgil by around 1
AD (White, 1967; Fowler, 2002). The plow with iron
share was widely used in Europe about fifth century AD,
and the Roman plow evolved into a soil-inverting plow
during 8th to 10th century AD (Lerche, 1994). The major
advance before 1000 AD was the development of the
heavy plow, which was more than the simple plows
farmers used earlier. It had a coulter designed to cut a
thin strip in the turf (Fig. 2). The coulter was followed
by a share that would slice into the soil and then the soil
would ride up the moldboard and subsequently be
turned over. Later, wheels were attached to this type of
plow and eventually a seat was added. By turning over
the soil, crop residues were incorporated and organic
matter mineralized, weeds were limited and overall it
helped the growing process. A parallel evolution of
plow tillage through the centuries in Ethiopia was
reviewed by Gebregziabher et al. (2006). While there
may be a few specific cultural differences, the similarity
to other parts of the world is remarkable.
Editorial / Soil & Tillage Research 93 (2007) 1–122
Fig. 1. One of the earliest tillage tools that evolved from ‘‘digging
sticks’’ to be pulled by animals or humans, sometimes referred to as
the ‘‘ard’’. (Redrawn from Glob, 1951, and others).

A moldboard plow used in the U.S. was designed by
Thomas Jefferson in 1784, patented by Charles Newfold
in 1796, and marketed in the 1830s as a cast iron plow
by a blacksmith named John Deere. The use of plows
expanded rapidly with the introduction of the steam
horse in 1910 (Olmstead and Rhode, 2001). By 1940,
there were 2 million tractors in the U.S. (Danbom,
1995). Introduction of tractors enhanced farm income,
which rose as much as 156% between 1939 and 1944
(Danbom, 1995). As new technology evolved, farmers
in the U.S. got equipped with some of the largest
equipment in the world (Fig. 3). Use of powerful
tractors and large machinery along with fertilizers and
improved varieties enhanced crop yields by a factor of
3–5. The ratio of civilian to agriculturally employed
population increased from 10.5 in 1940 to 63.0 in 2000,
and the number of farms decreased from 5.65 million in
1950 to 2.17 million in 2000 (Table 1). The number of
people fed by one U.S. farmer increased exponentially
during the 20th century (Fig. 4).
3. Environmental implications of plow tillage
Intensive tillage and use of heavy machinery brought
mixed blessings. Accelerated soil erosion has plagued the
earth since the dawn of settled agriculture, and has been a
major issue in the rise and fall of early civilization
(Diamond, 2004). With increasing demand on the limited
prime soil resources and shrinking per capita arable land
area in densely populated regions of the world, soil
erosion has became a global issue with regard to its on-
site impact on productivity and agricultural sustain-
ability. Both water and wind erosion are exacerbated by
plow tillage. It loosens the soil, buries crop residues and
exposes the soil to high-intensity rainfall and high wind
speeds that lead to severe erosion. Intensive tillage
systems leave the soil bare allowing rain to pulverize it
excessively, creating conditions where soil and nutrients
are carried away by heavy rains. Later, the surface sealing
Editorial / Soil & Tillage Research 93 (2007) 1–12 3
Fig. 2. Early model of the ‘‘iron share’’ plows with coulter designed to
cut a thin strip in the sod share that would slice into the soil and ride up
the moldboard and subsequently be inverted. (Redrawn from White,
1967;Fowler, 2002;Lerche, 1994; and others)
Fig. 3. A large modern moldboard plow used in the north-central U.S.
agricultural production areas.
Table 1
Trends in U.S. agriculture during the second half of the 20th century (FAO, 2006;CIA, 2006)
Year Total civilian
population (millions)
Agricultural
employment (millions)
Ratio of civilian:
agricultural population
Farm number
(millions)
1940 100 9.5 10.5 –
1950 105 7.2 14.6 5.65
1960 117 5.5 21.3 3.96
1970 137 3.5 39.1 2.95
1980 168 3.4 49.4 2.44
1990 189 3.2 59.1 2.15
2000 208 3.3 63.0 2.17
Fig. 4. The increasing number of people fed by one U.S. farmer in the
20th century (adapted from Brown, 1999; Seitz, 1985).

dries, resulting in crusting that may hinder or impede the
germination and emergence of crop seeds. This
accelerated soil erosion and other degradation processes
influence agronomic productivity and environment
through their impact on the physical, chemical and
biological factors related to soil quality.
Accelerated erosion is one of the causes of soil
degradation, others being soil C loss and nutrient
depletion, soil compaction, acidification, pollution, and
salinization. Currently, the average rate of soil erosion
on U.S. cropland is 15.7 Mg ha
1
year
1
(Sullivan,
2004). The most ubiquitous form of erosion is that
caused by water and leads to increased runoff and off-
site degradation. When uncontrolled, agricultural runoff
removes topsoil, nutrients, pesticides, and organic
materials and carries them to water bodies where they
become pollutants.
Sediment fills streams, rivers, reservoirs, lakes and
roadside ditches, reducing their useful life. The once-
productive soil then becomes a costly maintenance
problem since the sediment must be removed to provide
adequate water-carrying capacity and to prevent flood
damage. In addition to loss of storage capacity, the
sediment fills water bodies and impairs water quality.
When runoff enters a water course, the lighter soil
particles remain in suspension and block sunlight vital
to the growth of desirable, oxygen-producing plants
living in the water. Sediment-darkened water also
absorbs more heat from sunlight than clearer water, thus
causing warming. The combination of warm and muddy
water leads to ecological shifts by replacing desirable
fish species with less desirable types more tolerant to
these conditions.
Nutrients and pesticides that may be present in
agricultural runoff also cause serious economic and
environmental problems. The direct effect on the
producer is the economic losses connected with
removing these materials from the field. In addition,
nutrients derived from soil, commercial fertilizers or
animal manure may cause excessive algal growths in
ponds and lakes. These growths filter out and absorb
sunlight, and release offensive odors and toxicants.
Pesticides are as toxic in the water as they are on the
field and may affect a wide variety of aquatic organisms.
If contacted or ingested in sufficient quantity, pesticides
pose a health hazard to all forms of life. Water supplies
can be jeopardized by the presence of pesticide or algal
growths, and purification expenses must be endured by
the producer as well as other users.
Erosion is also caused directly by the action of tillage
implements. Tillage erosion, the progressive downslope
movement of soil through the action of tillage
implements, is also a serious problem that needs to
be considered during the development of conservation
management plans (Lindstrom et al., 2001). Landscapes
subject to tillage erosion are topographically complex
or have a high number of field boundaries. Tillage
erosion increases landscape heterogeneity through
creation of distinct landforms and relatively rapid
redistribution of soils from upland positions to
depressions. Severe adverse impacts of tillage erosion,
now widely recognized, are directly proportional to
degree and scale of topographic complexity (Lindstrom
et al., 2001; Lobb et al., 2004). The magnitude of soil
translocation from upslope positions, either convex
slopes or upper field boundaries, can result in soil
loss that greatly exceeds what would be considered
sustainable. Interactions between tillage and water
erosion requires that both processes be considered when
developing conservation plans. The net effect of soil
erosion, either tillage or water erosion, is an increase in
field variability and a reduction in crop production
potential (Lobb et al., 2004). Conservation planners and
practitioners can use the information to develop more
effective conservation plans insuring the long-term
sustainability of agricultural production.
4. Plow tillage and the dust bowl
Historically, the moldboard plow was an essential tool
for the early pioneers in settling the prairies of central and
western U.S. and Canada. The moldboard plow has been
a symbol of U.S. agriculture since about 1850. It allowed
the farmer to create a soil environment in which grain
crops could thrive and meet the needs of the increasing
population. At the same time, it degraded soil from
increased water, wind and tillage erosion. Plowing also
decreased the soil organic matter (SOM) concentration
because of increase in rate of mineralization with an
attendant release of plant-available nutrients (e.g., N, P,
S). While plowing improved soil fertility and agronomic
productivity, it set in motion a long-term trend of decline
in soil structure and increase in susceptibility to crusting,
compaction and erosion. In drier areas, other types of
chisel plows and large sweeps developed as primary
tillage tools with similar impact on the crops and
available water (Reeder, 2000; Owens, 2001).
The ‘‘Dust Bowl’’ was as much about tillage as it was
about drought. The combination of intensive tillage and
drought resulted in the catastrophe. Poor agricultural
practices and years of sustained drought caused the Dust
Bowl which lasted for about a decade. The rainfall
received in 1934 and 1936 was less than half of the
normal. Although droughts and dust were recorded
Editorial / Soil & Tillage Research 93 (2007) 1–124

during the 1850s and 1860s, the scale and frequency of
storms during the 1930 s was alarming. A dust storm in
May 1935 carried an estimated 350 million tons of soil
into the air, of which 12 million tons were dropped on
Chicago, and also as far east as Buffalo and New York
(Danbom, 1995)(Fig. 5). A documentary film by
Lorenz, ‘‘The Plow that Broke the Plains’’ blamed the
Dust Bowl on excessive plowing (Danbom, 1995). The
book, ‘‘Grapes of Wrath’’ narrated the plight of
migrants from Oklahoma called ‘‘Okies’’ (Steinbeck,
1939). Therefore, people developed a keen interest in
farming methods that would reduce water erosion and,
even more important to the U.S. Southern Great Plains,
wind erosion.
The soil erosion crisis of America, highlighted by the
Dust Bowl storms, prompted the U.S. Congress to take
action. Hugh Hammond Bennett led the soil conservation
movement in the U.S. in the 1920s and 1930s, and urged
the nation to address the ‘‘national menace’’ of soil
erosion. Bennett’s crusading zeal for conservation was
born of his experiences studying soils and agriculture
nationally and internationally. The gullied land as well as
the less visible evidences of what he called sheet erosion
convinced him of the need for conservation. Bennett’s
actions led to congressional establishment of the Soil
Conservation Act in 1935, a new federal agency, the Soil
Conservation Service (SCS), now the Natural Resources
Conservation Service (NRCS) in the U.S. Department of
Agriculture (USDA). Bennett’s flair for showmanship
and his evangelistic commitment to soil conservation,
convinced national leaders and farmers alike for the need
to conserve soil and water resources (Bennett, 1939). As
early as 1937, President Franklin D. Roosevelt stated in a
letter to the state governors that ‘‘A nation that destroys its
soils destroys itself.’’ President Franklin D. Roosevelt
sent to the governors of all states legislation that would
allow the formation of soil conservation districts to
extend the battle against soil erosion (Roosevelt and
Franklin, 1937). Prior to the U.S., a Soil Conservation
Service was initiated in Iceland in 1907. The Icelandic
SCS is probably the oldest among such institutions in the
world (Arnaulds et al., 2001). Many countries of the
world developed soil conservation departments during
the second half of the 20th century.
5. Transition from moldboard plow to less
intensive tillage
The Dust Bowl created a controversy about the
usefulness of ‘‘moldboard plow’’ as a tool for seedbed
preparation. There were two strong but opposing
schools of thought: no-till and plow tillage. The no-
till movement was spearheaded by Edward Faulkner,
who wrote the book ‘‘Plowman’s Folly’’ published in
1942 (Faulkner, 1942b). Faulkner, an extension worker
in Ohio thus opined: ‘‘Briefly, this book sets out to show
that the moldboard plow which is in use on farms
throughout the civilized world is the least satisfactory
implement for the preparation of land for the production
of crops. This sounds like a paradox, perhaps, in view of
the fact that for nearly a century there has been a science
of agriculture, and that agricultural scientist almost to a
man approved use of the moldboard plow...The truth is
that no one has ever advanced a scientific reason for
plowing.’’ (Quoted from page 3, paragraph 1.) While
some refer to plowing as ‘‘recreational tillage,’’ plowing
enhances soil fertility and increases agronomic yield
when fertilizers are not used. Certainly, the bountiful
harvest from many soils depended largely on the fact
that these soils were tilled to mineralize SOM to make
nutrients available.
Faulkner (1942a) continued the discussion on the
traditional aspects of the plow: ‘‘The answer to the
question, Why do farmers plow? Should not make it
Editorial / Soil & Tillage Research 93 (2007) 1–12 5
Fig. 5. Typical scenes from the mid-1930 ‘‘dust bowl’’ days in the
Great Plains of the U.S.: (a) intense dust storms in Texas; (b)
deposition of windblown soils on a farm site.

difficult to arrive at. Plowing is almost universal.
Farmers like to plow. If they did not get pleasure from
seeing the soil turned turtle, knowing the while that by
plowing, they dispose of trash that would later interfere
with planting and cultivation, less plowing might be
done. Yet farmers are encouraged to plow. The plowing
is approved; or, you knew of the plowing, farmers are
advised to cut deep into the subsoil in every furrow.
Such advice comes from farm papers, bulletins, county
agents, and a long list of other sources from which
farmers commonly welcome suggestions and informa-
tion. There should be clear-cut scientific reasons to
justify a practice so unanimously approved and
recommended.’’ (Quoted from page 43, paragraph 1.)
The irony demonstrated in Faulkner’s comments is
summarized in the following statement ‘‘The entire
body of’’ reasoning ‘‘about the management of soil has
been based on the axiomatic assumption of the
correctness of plowing. But plowing is not correct.’’
(Quoted from page three, paragraph 2.)
The opposite view, strongly in favor of using
moldboard plow, was spearheaded by Walter Thomas
Jack in the book, ‘‘Furrow and Us’’ published in 1946.
Views by Jack were based on the common observations
of increase in soil fertility through mineralization of
SOM by plowing. Jack thus opined, ‘‘The method of
stirring the soil without turning under the top with its
crop residues was practiced by primitive people of every
land since the beginning of time. The principle was
outmoded with the advent of the woodboard type that
turned only a portion of the surface under, since the
wood surface could not be induced to scour.... Only
after it was discovered that soil building agencies were
living organisms supplying fertility and tilth to the soil,
was the present moldboard plow designed’’ (Jack, 1946,
p. 19). In the same writing, Jack presented his views on
science of agronomy by stating, ‘‘Those hostile to
present tillage practice (plowing) point out that, since
most of the N requirement of the plant comes from the
air, there is no need to encourage soil bacteria to supply
the major portion, therefore the organic matter in the
form of trash and manure has just as well remain on the
surface as a guard against erosion. This argument seems
to be a radical departure from the true principle of
agronomy’’ (Jack, 1946, p. 20).
This controversy between ‘‘no-till’’ and ‘‘plow
tillage’’ was dubbed by Time Magazine as the ‘‘hottest
farming argument since the tractor first challenged the
horse’’. The plow tillage argument won, especially in
the South, where the clay ridden thin soils and perennial
poverty made N dependent no-till methods impractical
during the 1950s and 1960s.
Since the 1950s, there’s been a gradual transition
from the moldboard plow to various forms of
conservation tillage to no-till with minimum soil
disturbance throughout the world (Hood et al., 1963,
1964; Jeater and Mcilvenny, 1965; Triplett and Van
Doren, 1969; Kuipers, 1970; Blevins et al., 1971;
Reeves and Ellington, 1974; Lal, 1974, 1976a,b;
Phillips et al., 1980; Cannell et al., 1980; Carter and
Rennie, 1982; Vaidyanathan and Davies, 1980; Derpsch
et al., 1986; Owens, 2001). Conservation tillage is a
term used to describe a number of technologies that are
utilized in agriculture to conserve water and soil.
Emphasis is placed on decreasing the amount of soil
disturbance and managing crop residues to protect the
soil surface. Conservation tillage practices include,
amongst others, strip tillage, cover cropping, contour
farming, zero or chemical tillage, mulch tillage, and
reduced tillage, with the ultimate being low disturbance
no-till or direct seeding (Unger, 1984).
Since the 1970s, new technology has been redefining
these operations where tillage and planting are combined
in conservation tillage and where mechanical cultivation
has been replaced by herbicides. Modern, large farm
equipment can perform these operations easily and
quickly with one pass. New tillage systems with
emphasis on crop residue management and soil
conservation will encompass new technology and
continue to evolve around the best systems within a
given geographic location as driven by economic and
environmental considerations (Reeder, 2000; Coughe-
nour and Chamala, 2000; Owens, 2001). As new
agricultural tillage and planting practices are developed
across the world, their impacts on the environment and
energy use will need to be evaluated critically to ensure
their compatibility and sustainability with societal needs.
Peak plow production in the U.S. occurred in the
1950s and 1960s when 75,000 to 140,000 units were
shipped annually (USDA, 1965, 1977; Reicosky and
Allmaras, 2003). In the late 1980s to 1990, fewer than
3000 moldboard plows were shipped annually in the
U.S., and the number of moldboard plows shipped by
manufacturers dropped from 46,300 in 1977 to 1400 in
1991 (USDC, 1992). Some of the impetus for change
came from the new farm bills and stewardship
incentives that encouraged conservation farming. The
primary reasons given by farmers for this transition
away from the plow were efficiency, equipment width,
and speed which the multiple combination tillage tools
can be pulled through the soil. Other reasons for going
away from the moldboard plow range from no more
‘‘dead furrows,’’ no headlands, higher skilled operators,
leaving residue on the surface for decreased erosion and
Editorial / Soil & Tillage Research 93 (2007) 1–126

to overall economics. The moldboard plow may have
special uses depending on soil type and wetness, but
combination tillage tools recently have become more
prevalent over much of the U.S.
The no-till movement began with the invention of
2,4-D after World War II, and development of paraquat
by ICI in U.K. (Hood et al., 1963, 1964). In the early
1960s, no-till agriculture was not widely supported
among farmers and agriculture specialists in the U.S. It
was intended to be a way of farming without losing a
great deal of soil, but few thought that no-till would
make a difference in farming. A few no-till pioneers
were instrumental in exposing agriculture to these new
techniques. At The Ohio State University, David Van
Doren and Glover Triplett initiated long-term no-till
plots in 1962 at Wooster, South Charleston and
Hoytville. These are the longest running no-till
experiments in the world. At the University of
Kentucky, Shirley Phillips, extension specialist and
farmer, Harry Young enthusiastically promoted no-till
agriculture (Phillips and Young, 1973; Phillips and
Phillips, 1984). George Elvert McKibben, an agrono-
mist with the University of Illinois, helped make no-till
the accepted farming technique that it is today.
Believing in his cause, McKibbben said, ‘‘I was
convinced from the start that it would succeed.’’ The
basic principles of no-till agriculture include the
following:
Growing crops without using traditional tillage.
Using special planting equipment that cuts through
the residue mulch.
Using seeders that require four-wheel tractors,
although the seed can be dibbled in by hand (often
using sticks to make the opening), or some small
equipment suitable for animals or hand tractors.
Retaining surface residue that reduces erosion,
evaporation and limits weed growth.
Sowing directly into the soil covered by residue
mulch.
Improving water infiltration capacity by ameliorating
effects of residue mulch which provides bioturbation
and enhances macro-porosity despite some increase
in bulk density.
No-till implements are specifically designed for the
management of crop residue left on the soil surface
(Fig. 6). Most tillage practices bury or remove large
amounts of crop residue. For example, the moldboard
plow retains less than 10% of the residue, the chisel plow
and disking retain between 25 and 75% of the residue,
disking 25–75%, and ridge-planting and till planting
retain about 40–60% of residue (CTIC, 2006). No-till
agriculture on the other hand retains more than 90% of
the crop residue, and the seeder is specifically designed to
cut through the residue and sow seed in a small furrow
(Fig. 7). Residue mulch is essential to reducing losses by
erosion (Table 2), even on steep slopes (Harrold and
Edwards, 1972). It is a conservation-effective measure.
Currently, no-till farming is practiced globally on about
95 Mha of cropland worldwide (Derpsch, 2005), and is
likely to expand especially in Asia.
No-till agriculture has gained acceptance in South
America at a faster rate than in the U.S. The rate of
conversion from plow tillage to no-till has been high in
Brazil, Argentina and Chile. In addition to high rate of
adoption, no-till system observed in South America has
been on a continuous basis. In contrast, no-till practiced
in the U.S. Corn Belt has been rotational: 1 year no-till
and the second year chisel till. Another variance of
rotational no-till is observed in the rice-wheat system in
Editorial / Soil & Tillage Research 93 (2007) 1–12 7
Fig. 6. No-till soybean seeded through the crop residue.
Fig. 7. A no-till seeder fitted with a fluted disk which can cut through
the crop residue mulch and place seed in a narrow slot. The seed is
covered by a press wheel that follows the slot opener.

the Indo-Gangetic plains of South Asia (Lal et al.,
2004). While rice is grown in an intensively puddled
field to deliberately destroy soil structure and reduce
seepage losses, the following wheat crop is grown by a
no-still system with or without burning the rice straw.
The system is gaining popularity not so much for soil or
water conservation but for saving time needed in the
conventional plow-based method of seedbed prepara-
tion. Late planting of wheat results in yield reduction
and poor quality of grains due to onset of hot weather at
the grain ripening stage of wheat (Lal et al., 2004). No-
till sowing of wheat was practiced on almost 2 Mha in
the Indo-Gangetic plains in 2005. Despite the progress,
there is a strong need to develop systems of direct
seeding of rice in an unpuddled soil followed by no-till
sowing of wheat through the stubble mulch of rice
straw. This technology remains to be a high research
and development priority.
In addition to erosion control, no-till also saves
energy (Lal, 2004a). It utilizes less fossil fuel energy
than plow tillage. With diverse crop rotations including
legumes, fertilizer use efficiency is also enhanced which
further reduces the energy input (West and Marland,
2002). In view of rising energy costs, the five typical
operations in traditional agricultural production
(including tillage, planting, cultivating, harvesting,
and processing, transporting, and storage) must be re-
examined in light of the need for energy conservation.
During the 20th century, agriculture has undergone vast
transformations in the U.S. The number of farmers has
decreased, more farmers are relying on off-farm
income, agriculture’s contribution to the U.S. gross
domestic product has declined, and a minority of non-
metro counties in the U.S. are farming dependent.
Productivity per unit input of energy is the principal
criteria of success.
The transition to no-till has implications to environ-
mental quality for its effectiveness in controlling soil
erosion and runoff, increasing water infiltration,
enhancing SOM concentration, increasing soil biolo-
gical activity, and saving energy. The transition to no-
till also has technical implications for farmers in
determining crop rotations, using cover crops, selecting
suitable soil type, managing residues, selecting crop
varieties and seeding rate, controlling pests, managing
soil fertility and pH, and choosing the right equipment.
This complex and integrated technology must be
understood and implemented to protect soils for
sustainable productivity. No-till farming can provide
all of the above with nonfood producing functions that
also create environmental and ecological benefits. No-
till farming also increases farm wildlife for pest and
disease control, creates biodiversity, cleans water and
air, increases aesthetic value, provides recreation and
other amenities, increases water accumulation, storage
and management, provides storm protection and flood
control, strengthens nutrient cycling and fixation of C
and N, increases C sequestration in soils and trees,
provides jobs and contributes to the local economy.
Proper use of the full no-till system approach improves
food production efficiency, profitability, and environ-
mental stewardship important to all society.
6. No-till and carbon sequestration
The most important factor in determining soil quality
is the SOM. Decline in SOM concentration under
conventional plow tillage occurs independent of soil
erosion. In the U.S. Corn Belt, intensive tillage has
caused a soil C loss between 30 and 50% (Schlesinger,
1985), leading to emission of greenhouse gases
(GHGs), and the attendant global warming. The ‘‘bigger
the better’’ approach to plowing has exacerbated the
problem of soil erosion and non-point source pollution
on undulating terrains. Increase in SOM mineralization
also accentuates CO
2
emission following plowing.
The short-term impact of moldboard plow and
various tillage methods on CO
2
emission from the soil
can be evaluated using a portable dynamic chamber
mounted on a high clearance forklift implement. Using
this technique, it has been documented that there occurs
a rapid and severe loss of C immediately following
intensive tillage (Reicosky and Lindstrom, 1993).
Experiments conducted in Minnesota have indicated
Editorial / Soil & Tillage Research 93 (2007) 1–128
Table 2
Effect of mulch rate on runoff and soil loss in 1974 from Alfisols in
western Nigeria (adapted from Lal, 1976a,b)
Slope (%) Mulch rate (Mg ha
1
season
1
)
0 2 4 6 No-till Mean
(A) Water runoff (mm year
1
)
1 411.7 36.2 6.7 0.0 11.5 93.2
5 483.0 126.1 28.3 10.7 14.8 132.6
10 302.9 73.8 34.7 21.1 24.0 91.3
15 374.7 86.8 50.6 19.9 22.6 105.0
Mean 393.1 80.7 30.1 12.9 18.3
(B) Soil erosion (Mg ha
1
year
1
)
1 9.3 0.9 0.3 0.0 0.0 2.1
5 134.3 6.3 1.5 0.2 0.7 26.8
10 137.0 5.5 1.0 0.2 0.1 28.8
15 95.5 16.8 2.7 0.7 0.1 23.2
Mean 94.0 7.4 1.4 0.3 0.2
Total rainfall = 769.2 mm.

that the moldboard plow produces the roughest soil
surface, the highest initial CO
2
flux and maintains
thehighestfluxfortwotothreeweeksfollowingthe
tillage event. High initial CO
2
fluxes are related to the
depth of soil disturbance that results in a rougher
surface and larger voids than to residue incorporation.
Lower CO
2
fluxes result from tillage systems
associated with low soil disturbance and small soil
pores. No-till causes the least amount of CO
2
loss
during the 2–3-week period following tillage. Rei-
cosky and Lindstrom (1993) and Reicosky (1997,
1998, 2002) concluded that intensive tillage methods,
especially moldboard plowing to 0.25 m depth, affects
this initial soil flux differently and suggested improved
soil management techniques such as strip tillage or
forms of conservation tillage to minimize agricultural
impact on global CO
2
increase.
Concern for environmental quality and GHG
emissions (carbon dioxide, methane, nitrous oxide)
require knowledge of tillage effects on C emission. The
link between global warming and atmospheric CO
2
abundance has heightened interest in soil C storage in
agricultural production systems. Agricultural soils play
an important role in C sequestration or storage and thus
can help mitigate global warming (Lal et al., 1998).
Tillage processes and mechanisms, (e.g., tillage-
induced CO
2
efflux), lead to C loss and are directly
linked to soil productivity, soil properties and environ-
mental issues (Paustian et al., 1997). Soil C dynamics
indirectly affect climate change through net absorption
or release of CO
2
from soil to the atmosphere in the
natural C cycle. Carbon comes into the system through
photosynthesis and is returned to the atmosphere as CO
2
through microbial respiration accentuated by anthro-
pogenic intervention. A judicious management of SOM
is vital because of its role in maintaining soil fertility,
physical properties and biological activity required for
food production and environmental quality. Soil C
sequestration is also needed to partially offset GHG
emissions from manufacture and use of fertilizers,
liming and use of fossil fuels as well as to minimize the
release of more potent nitrous oxide and methane.
However, nitrous oxide emission may be greater under
no-till than plow tillage on many soils (Baggs et al.,
2003; MacKenzie et al., 1997; Linn and Doran, 1984;
Palma et al., 1997). Researchers in Michigan (Robert-
son et al., 2000) have suggested that nitrous oxide—
with nearly 310 times the global warming potential of
carbon dioxide needs to be factored into GHG
calculations. Nitrous oxides are associated with
fertilizer nitrogen use and, like carbon levels, can be
influenced by tillage regimes (Parkin and Kasper, 2006;
Steinbach and Alvarez, 2006; Liu et al., 2005; Dale
et al., 2005). Venterea et al. (2005) have shown that over
a 2-year period, the combination of anhydrous ammonia
fertilizer use and no-till can lead to nitrous oxide
emissions. The global potential of C sequestration if all
croplands were converted to no-till farming is
1 Pg C year
1
(Pacala and Socola, 2004). The rate of
SOC sequestration upon conversion from plow tillage to
no-till farming is 0.1–1.0 Mg C ha
1
year
1
(Lal,
2004b). Whereas plowing increases the rate of
mineralization and makes nutrients available for plant
growth, putting crop residue back into the soil will
cause nutrient immobilization. Conversion of crop
residue into humus would need additional nutrients for
humification. Thus, rate of nutrient application for
sustainable soil use must consider replacement of those
removed by crops, leached, lost in runoff, and for
humification of biomass C.
7. Challenges and opportunities in agricultural
research during the 21st century
The world population of a few million at the dawn
of agriculture has increased several fold to reach
6.5 billion in 2006. The population is likely to
stabilize around 10 billion towards the end of the
21st century. Yet, the future increase in population
will likely happen in the developing countries of
Africa and Asia, where soil resources are already
under great stress (Lal, 1989;Smil, 1987;Oldeman
et al., 1991). Future food demand of these countries is
expected to more than double over the next few
decades because of both the increase in population and
also change in diet from mostly vegetarian to
increasingly meat-based food. Yet, there are almost
one billion food insecure people in the world and there
is a growing consensus that the U.N. Millennium
Development Goals will not be realized. Thus, there is
a strong need to bring about a drastic increase in food
production in developing countries of Asia, Africa,
Latin America and the Caribbean.
The data in Table 3 outlines the chronological
development of yield-enhancing innovations. Past
developments in agriculture, with a notable impact
on productivity and population carrying capacity,
included evolution of a plow, use of supplemental
irrigation, and development of fertilizers. Future
innovative technologies will include developments
with regards to supply of water and nutrients directly
to plant roots to minimize losses and enhance use
efficiency, precision farming, conservation tillage, C
sequestration and land-saving technologies.
Editorial / Soil & Tillage Research 93 (2007) 1–12 9

8. Conclusion
Agriculture, as we know it, evolved over 10–13
millennia, and is destined to undergo remarkable
change during the 21st century. Eight current trends
that will affect future agricultural development include:
(1) increased risks of soil degradation; (2) competing
soil uses; (3) focus on ecosystem services; (4) increase
in farm size; (5) movement toward commercialization;
(6) genetic engineering; (7) global markets; (8)
changing social structure. Soil management systems
will have to be developed to address these emerging
issues. While it is certainly not a panacea, conversion of
plow tillage to no-till farming can address some of the
issues by providing alternatives that are environmen-
tally and economically compatible and sustainable
while maintaining a high degree of social acceptability.
The agricultural community will face many new and
difficult challenges in the years to come, including: (1)
competitive pressures; (2) sustainable development; (3)
resources conservation; (4) research and development.
New agricultural management systems need to be
developed that include consideration and inclusion of
economics and economic policies, environmental
sustainability, social and political concerns, and new
and emerging technology. These systems can ultimately
assist land managers to develop new and improved
sustainable land-use strategies. In some soils and
climates, no-till farming can address the emerging
issues of the 21st century: global climate change,
accelerated soil degradation and desertification, decline
in biodiversity, and achieving food security for the
expected population of 10 billion in 2050. Replacement
of plow tillage by no-till farming, based on crop residue
management and use of leguminous cover crops in the
rotation cycle, can achieve positive nutrient balance by
using manures and other biosolids, and increase C
storage in soil and terrestrial ecosystems. The no-till
soil and crop residue management system promotes soil
carbon storage and long-term sustainable agriculture
that provides food, fiber, biofuels, ecosystem services
and environmental benefits for all of society.
Acknowledgements
The authors gratefully acknowledge contributions of
Cal Thorson, USDA-ARS, Mandan, ND that provided
the initiative to the development of this manuscript.
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tillage practices in the United States. Agric. Ecosyst. Environ. 91,
217–232.
White, K.D., 1967. Agricultural Implements of the Roman World,
Cambridge.
R. Lal*
Carbon Management and Sequestration Center,
School of Environment and Natural Resources,
The Ohio State University, 422B Kottman Hall,
2021 Coffey Road, Columbus, OH 43210, USA
D.C. Reicosky
1
USDA-ARS, 803 Iowa Avenue,
Morris, MN 56267, USA
J.D. Hanson
2
USDA-ARS, Northern Great Plains
Research Laboratory, P.O. Box 459,
Mandan, ND 58554, USA
*Corresponding author.
Tel.: +1 614 292 9069
E-mail addresses: Lal.1@osu.edu (R. Lal)
reicosky@morris.ars.usda.gov (D.C. Reicosky)
jon@mandan.ars.usda.gov (J.D. Hanson)
1
Tel.: +1 320 589 3411x144.
2
Tel.: +1 701 667 3010.
Editorial / Soil & Tillage Research 93 (2007) 1–1212