BookPDF Available

Practical Guide to Conservation Agriculture in West Asia and North Africa

Practical Guide to
Conservation Agriculture in
West Asia and North Africa
a Research Leader, INRA Morocco, La Victoire Avenue, Rabat 10000 Morocco
b Independent International Consultant, La Cañada 177, Sector O, Bahias de Huatulco, Oaxaca 70989, Mexico
Rachid MRABETa & Patrick WALLb
Copyright and Fair Use:
is publication is licensed for use under the Creative Commons
Attribution-Non-commercial-Share Alike 3.0 Unported Licence. To view this licence,
visit Unless otherwise noted, you
are free to copy, duplicate, or reproduce and distribute, display, or transmit any part
of this publication or portions thereof without permission and to make translations,
adaptations, or other derivative works under the following conditions:
ATTRIBUTION. e work must be attributed, but not in any way that suggests
endorsement by the publisher or the author(s)
NON-COMMERCIAL. is work may not be used for commercial purposes.
SHARE ALIKE. If this work is altered, transformed, or built upon, the resulting
work must be distributed only under the same or similar license to this one.
International Center for Agricultural Research in the Dry Areas (ICARDA), PO Box
114/5055, Beirut, Lebanon
Objectives and beneciaries of this guide.....................................................................................................3
Why do we need a change?............................................................................................................................3
What are CA and no-tillage systems?.............................................................................................................4
e benets of CA systems...........................................................................................................................7
Soil quality..................................................................................................................................................................8
Agronomic impacts...................................................................................................................................................8
Economic benets......................................................................................................................................................8
Food security issues...................................................................................................................................................9
Social and societal benets of CA systems.................................................................................................10
CA and environmental stewardship.......................................................................................................................10
CA and climate change..................................................................................................................................10
Adaptation to climate change................................................................................................................................11
Mitigation of climate change.................................................................................................................................12
Diculties with CA........................................................................................................................................12
e principles of CA.....................................................................................................................................14
e importance of not disturbing the soil..........................................................................................................14
e importance of crop residues.........................................................................................................................15
Increased water inltration....................................................................................................................................16
Reduced soil erosion................................................................................................................................................17
Crop residues and water erosion mitigation........................................................................................................17
Crop residues and wind erosion reduction...........................................................................................................17
Crop residues, evaporation, and soil temperature..............................................................................................18
Crop residues and water storage............................................................................................................................18
Crop residues and the soil fauna and ora............................................................................................................18
Crop residues and soil organic matter.................................................................................................................18
e importance of crop rotation...........................................................................................................................19
Practical aspects of CA................................................................................................................................19
Equipment for seeding into untilled soil............................................................................................................19
Crop management...................................................................................................................................................23
Cropping systems....................................................................................................................................................23
Sustainable weed management in CA...................................................................................................................24
Ecient application of herbicides.........................................................................................................................26
Integrated disease and insect control..................................................................................................................28
Soil fertility management.......................................................................................................................................29
Management of the crop residue cover..................................................................................................................30
Livestock in CA systems.......................................................................................................................................30
Top ten practical factors for CA adoption..........................................................................................................32
CA: lessons learned from other countries..................................................................................................32
State of CA in WANA..................................................................................................................................34
Critical factors in promoting CA adoption in WANA...............................................................................35
e innovation platform........................................................................................................................................36
Objectives and beneficiaries of this guide
Conservation agriculture (CA) is a new method of agricultural production that is
more productive and environmentally friendly than the common form of agriculture
based on plowing and intensive soil tillage. However, adopting CA is not an easy
process and involves a change not only in the way we think of agriculture, but also in
agricultural policy and the institutions that support agricultural production, including
input and output markets, credit, and research and extension systems.
is manual serves as an introduction to CA, a guide to the benets and diculties
associated with its adoption, and an introduction to the practical application of CA,
together with some scientic background as to why the system works. As such, the
guide aims to help farmers, extension specialists, researchers, and all stakeholders
involved in agricultural production understand the principles and practices of CA,
and why changing to the new system is necessary. Furthermore, the guide sets out the
steps necessary for successful adaptation, adoption, and implementation of CA, and
describes the practices and equipment necessary for success. However, there is no
recipe for a successful CA system, and adaptation to local conditions and farmer needs
is always required. ose interested in CA are advised to contact farmers and techni-
cians with experience in the system before embarking on the journey to sustainable
agricultural production. e experience of these practitioners can help avoid the same
mistakes being repeated and can be an invaluable aid in answering queries and over-
coming doubts related to CA.
Why do we need a change?
Soil and land degradation are serious and widespread in the West Asia and North
Africa (WANA) region (and in many other parts of the world). Although ocial
gures (IAASTD, 2008) show that most of this degradation is due to wind and water
erosion, there are other underlying factors which make the land more susceptible to
erosion. Tillage leads to the breakdown of soil structure, leaving pulverized soil that is
highly susceptible to erosion, compaction, and crusting. At the same time tillage leads
to a reduction in soil organic matter – the key to soil fertility and soil health. Removal
of all or most of the crop residues by grazing reduces the return of organic matter to
the soil and exacerbates the eects of tillage in reducing soil organic matter. Soil fauna
and ora depend on a continuous supply of organic material for their existence; and in
bare soils depleted of plant material, biological activity is drastically reduced to the
point where the soil is little more than an inert structureless medium.
As a result of soil degradation, and largely due to the reduction in soil organic matter,
soil fertility declines, and because less water enters the soil, and less of the water that
does enter the soil can be retained because of the lack of pore space, crop yields
decline. Farmers can get over some of the eects of soil degradation by adding more
nutrients, either as organic or inorganic amendments, and/or by irrigation, but these
are expensive practices and so the protability of agriculture is reduced.
is downward spiral of soil fertility, crop yields, and protability is clearly not sustain-
able. New agricultural methods that allow for protable and productive farms are
required to ensure the food security not only of the present generation but also of
future generations.
What are CA and no-tillage systems?
In the second half of the twentieth century, farmers, researchers, and extension person-
nel in various parts of the world became alarmed about the levels of land and soil degra-
dation, and began to look for new ways of conducting agriculture that did not damage
the soil and the environment. Most of the solutions focused on doing away with soil
tillage, and replacing this with direct seeding of crops into untilled soil. e systems
were known as direct seeding, no-tillage, or zero tillage (and their equivalents in
various languages). However, it soon became obvious to early researchers (e.g.
Derpsch et al., 1991) that doing away with the tillage component of conventional
agriculture was not the only change needed, permanent soil cover with living crops
and crop residues was also required, as well as crop rotation, especially for overcoming
problems of crop diseases. For this reason a new name for the system was sought that
conveyed the idea of a complete agricultural system and, in the 1990s, practitioners
began to use the term ‘Conservation Agriculture. e term was formalized by FAO
(2002) as a system based on minimizing soil movement, permanent ground cover, and
crop rotation that allowed for the management of agro-ecosystems for improved and
sustained productivity, increased prots and food security while preserving and
enhancing the natural resource base and the environment.
CA is oen confused with the term ‘conservation tillage’. is latter term was devel-
oped in the USA to describe reduced tillage systems developed aer the Dust Bowl era
of the 1930s. Conservation tillage (CT) is dened as any system that leaves at least 30%
of the soil surface covered with crop residues aer crop sowing. While the ground
cover aspect is consistent with CA, CT systems oen include considerable soil move-
ment with vertical tine implements which is not consistent with CA. CT also focuses
on the tillage part of the system, whereas CA describes the whole agricultural system.
As stated above, CA describes farming systems that embrace three principles (Figure 1):
Minimum soil disturbance without soil inversion, achieved with direct seeding
using specialized equipment that allows crop seeds (and fertilizer) to be placed
into untilled soil through the surface residues;
Permanent soil cover with living crops or crop residues. Residues can be both
standing stubble or loose (at) residues;
• Crop rotations to reduce crop diseases and increase diversity, resilience, and soil
It is important to understand that these are principles (not xed technologies), and
that the way these principles are applied will vary from place to place depending on
climate, cropping patterns, farmer assets, and many other conditions. For instance,
large farmers in the Americas, Australia, and Kazakhstan practice CA using large
mechanized (tractor mounted) seeders and sprayers whereas small farmers in south-
ern Africa also practice CA systems, but using hand hoes or dibble sticks and back-
pack sprayers or manual weeding. In South Asia, CA systems, oen using two wheel
tractors, may incorporate manual seeding of relay crops into another standing crop to
increase cropping intensity. Although the CA principles are universal, the way they are
applied in a particular situation needs to be tailored to local needs and conditions.
is is as true in the WANA region as anywhere else.
Generally farmers do not adopt all of the principles of CA at the same time. Common-
ly direct seeding is the rst component adopted, oen without the retention of many
crop residues, as has happened in Iraq and Syria. Keeping more surface residues may
be the second component adopted, and the adoption of crop rotations may come later.
However, this again depends on local situations and in North Africa we have seen
instances where farmers adopt a new crop rotation before they manage to maintain
crop residues.
CA is not a technology or a group of technologies but rather a new form of agriculture
that involves the whole farming system (Figure 2). Another way of looking at CA is
that it is a type of agriculture that removes the negative, unsustainable components
from productive, conventionally tilled systems (the plowing, lack of crop residue reten-
tion, and monoculture are removed from conventional systems) but all other compo-
nents of productive systems such as timely sowing, high yielding and disease-resistant
varieties, adequate plant populations, correct fertilization, weed control, and pest and
disease management still need to be followed (Figure 2). However, it is also true that
once the soil is not tilled and residues are le on the soil surface for several years, the
optimal management of many of these other factors changes, and so there are multiple
changes in the production system. e addition of new crops in the rotation adds
another component to these already complex changes.
Figure 1. e three key principles underlying CA
Farmers, extension personnel, and scientists who are accustomed to soil tillage (that is
oen thought of as the key component of agriculture) may have diculty in believing
that crops can be grown without tillage. However, plowing is not a part of natural
systems – there is no plowing of forests and natural pastures – and yet these systems are
very productive. In these natural systems, leaves from a diverse set of plants fall, and
cover the soil surface forming a mulch. CA tries to make agriculture emulate as far as
possible natural vegetation systems.
Because it involves a change in the whole farming system, a switch to CA is not an easy
process. e farmer needs to obtain and manage much new knowledge, and extension
specialists and researchers play a major role in helping farmers obtain this knowledge.
Figure 2. CA requires a system approach
management Livestock
Crop residue
Minimum soil
Table 1. Benets and impacts of CA (Pieri et al., 2002)
Farm level Global levelCommunity/watershed level
• Labor, time, and farm power
savings through reduced
cultivation and weeding
• Lower costs due to reduced
operations and external inputs.
• Lower repair costs, longer life span
of equipment, and less fuel
• Better trafficability in the field, less
• More stable yields, particularly in
dry years due to improved
moisture and nutrient availability.
• Labor savings provide
opportunities for diversification
(livestock, high-value crops, and
• Increased profits (in some cases
from the beginning, in all cases
after a few years) due to increased
efficiency of the production
• More constant water flow in
rivers and streams, improved
recharge of the water table with
re-emergence of dried-up wells
and water sources.
• Cleaner water due to less
erosion and reduced
sedimentation of water bodies.
• Less flooding due to increased
infiltration; less damage from
droughts and storms.
• Improved sustainability of the
production system and enhanced
food security.
• Increased environmental
awareness and better
stewardship of natural resources.
• Lower municipal and urban
water treatment costs.
• Reduced rural road maintenance
• Increased farmer associative
• Improved rural livelihood and
quality of life.
• Improved carbon balance
through reduced carbon
emissions, less fuel and energy
consumption, and increased
carbon sequestration in the soil
organic matter.
• Better biodiversity protection at
the microflora and fauna levels
(e.g. increased soil biological
activity, bird nests in CA fields,
and fish in streams and ponds).
• Improved hydrological cycle at
the river basin and continental
• Reduced desertification and land
degradation, through lower risks
of soil erosion and enhanced soil
• Recharge of aquifers through the
capture and infiltration of rain
• Recognition of the role of rural
dwellers and farming activities in
providing key environmental
services to the society at large.
The benefits of CA systems
Because of the reduction in tillage and the increase in residue retention, there are
numerous benets that can be expected from CA systems. Many of these are on the
farm itself, while others occur at the watershed and community level – and some bene-
t the global community as a whole (Table 1).
Soil quality
Maintaining and developing soil quality and soil health is essential not only for current
crop production and agricultural sustainability, but also for environmental
stewardship. CA systems have an important inuence on soil physical, chemical, and
biological properties. Soil structure itself depends on small crumbs of soil called
aggregates, in which particles of sand, silt, and clay are held together largely by soil
organic matter. ese aggregates contain pore spaces that hold water. In a structurally
strong and healthy soil there are more, stronger (organic matter rich) aggregates, there
is more biological activity, more water is held in the soil, and the soil better resists the
passage of machines and animals that would otherwise cause compaction. Over time,
soil organic matter increases in most CA situations and this, together with the
associated increase in soil aggregation, is the major soil quality change associated with
CA implementation.
Research in the WANA region has shown that soil bulk density is reduced and water
inltration and retention are increased in CA systems through reductions in tillage and
stubble retention. In semi-arid Morocco, researchers have shown that under CA
systems the amount of large pores in the soil decreased, and the number and amount
of small pores increased in comparison to conventional tillage. e small pores are
important for storing moisture whereas the large pores drain quickly and hold little
water. e increased porosity is especially important for crop growth since it has a
direct eect on soil water and aeration, and enhances root growth.
Agronomic impacts
In a recent review, Kassam et al. (2012) stated that CA enables farmers to reverse crop
yield decline. e most important and primary benet generated by adopting CA in
the relatively dry WANA region, with its variable climate and frequent drought stress,
is increased and more stable crop yields. Reported yield dierences between CA
systems and tillage-based systems in the WANA region are in the range of 20–120%,
largely due to improved soil moisture and nutrient availability (Mrabet, 2008; 2011).
Economic benets
e economic advantages of CA are also numerous, but the time it takes to achieve
them are farm and situation specic. Over time, CA permits important cost savings, as
less labor, machinery, and fuel are required. In other terms, CA permits higher
eciency in crop production (more output for a lower input). Reduced labor use with
CA systems permits the development of other complementary agricultural and
non-agricultural activities, such as value-adding activities or o-farm work. Hence CA
increases the protability and competitiveness of both small and large farming
ere are three major changes in the costs of production in the early stages of adoption
of CA: equipment costs, a reduction in tillage costs, and oen an increase in the cost of
weed control. Adequate equipment for seeding directly into untilled soil is a pre-requi-
site for successful implementation of a CA system. While there are many no-till drill
choices and options, one thing is common among models – they are generally more
expensive than conventional-till drills: the prices of eective no-till grain drills are 2–5
times those of conventional drills. However, the greater cost associated with purchase
of a no-till drill may be oset by decreased total equipment costs. Furthermore, with
the exception of the initial purchase of a no-till seed drill, CA reduces investment in
agricultural machinery and extends tractor life due to lower draught requirements and
cleaner working conditions (less dust). It also reduces labor requirements and simpli-
es labor management.
Generally costs of production in CA are lower than those in conventional agriculture
because of the reduction in the cost of land preparation. However, in some instances
where weeds are a major problem and weed control is dicult, the increase in the cost
of weed control may oset some or all of the savings on tillage. In WANA, however, if
the crop is seeded with the rst rains, an extra application of herbicide may be unneces-
sary and the cost of post-emergence weed control is the same as in conventional
agriculture. Under these conditions the savings in the cost of production are immedi-
In studies in Syria, famer protability was shown to have improved by US$220/ha,
while in Iraq protability was $US355/ha higher (Piggin and Devlin, 2012). ese bene-
ts came from reduced costs in fuel, labor, and seed as well as from increased yields
resulting from the greater water use eciency.
While the economic benets of CA at the eld level may be clear, as evidenced by infor-
mation in the preceding paragraphs, the protability of farming overall depends on
adequate markets for inputs, outputs, and services – important bottlenecks in the early
stages of adoption of a technology or system that involves changes in equipment,
inputs, and/or crops. A key factor, therefore, in extending the use of CA is ensuring
that market limitations for key inputs and outputs, especially the produce from new
crops, are removed or reduced.
Food security issues
CA provides the best opportunity we have today for halting soil degradation and restor-
ing and improving soil productivity, all of which directly aect food security. Research
in WANA has shown that crop yields (mainly cereals) under CA systems tend to
increase over the years with yield variations decreasing. rough increased grain and
straw production, CA oers higher food and feed availability, as well as greater
income, and therefore access to non-farm food and feed items – equally important for
food security. Due to the more stable yields, CA systems are more secure, particularly
in dry areas and/or dry years as a harvestable crop can normally be obtained, even in
the toughest seasons.
Social and societal benefits of CA systems
WANA farmers are artists in surviving the severe and diverse environmental and
economic threats associated with conventional agriculture. By shiing to CA systems,
farm families will become even more resilient as a result of the increased productivity
and reduced risk. Drought is the most common environmental risk in the region, and
the increased eciency of use of rainfall under CA underpins the reduction of risk in
CA systems.
As shown by experiences around the world, CA holds benets not only for large farm-
ers, but also for small- and medium-sized farms. Whereas fuel and machinery savings
may be the biggest benet on large mechanized farms, labor savings and reduced
drudgery are oen the major benet reported by smallholder farmers. However, small-
holder farmers may need more support in terms of research, extension, information,
and services than their larger (and more resource-secure) counterparts. Because of the
multiple benets of CA systems, they are associated with the sustainability of rural
livelihoods, social equity, and rural development, and therefore merit policies that
support the adoption of these more sustainable agricultural systems.
CA and environmental stewardship
CA farmers contribute to the conservation of environmental public goods (Table 1),
especially of water, air, soils, and soil biodiversity. e CA system is one of few agricul-
tural practices that can deliver ecological services (Table 1) that benet farmers, socie-
ty, and the environment, including benets such as reduced erosion and downstream
sedimentation, improved aquifer recharge, carbon sequestration, and energy conserva-
tion, as well as cleaner surface water and air (Piggin and Devlin, 2012). Because of
these environmental services there are ongoing discussions in many regions as to how
society should compensate CA farmers for these services.
CA and climate change
Problems of land degradation, desertication, declining soil quality, reduced soil fertili-
ty, and low agricultural production levels may be irreversible if appropriate measures
are not taken soon. ese problems are exacerbated by climate change, which is predict-
ed to not only lead to drier conditions in WANA but also to greater variability in weath-
er conditions and a higher frequency of extreme events. It is predicted that the entire
WANA region will face severe and extreme drought and oods: predictions are that by
the end of the century there will be a 10–30% reduction in precipitation, with both
greater spatial variability (from site to site) and temporal variability (among seasons).
In this hotspot of climate change, it is important to develop technical, policy, market,
and investment conditions that facilitate sustainable agricultural development and
food security in the face of climate change. is will involve three main pillars:
1. Sustainably increasing agricultural productivity and incomes;
2. Adapting and building resilience to climate change, where resilience refers to the
capacity of the farmer, the community, and the country to recover from extreme
climatic shocks;
3. Mitigating further climate change by reducing, or preferably stopping, greenhouse
gas (GHG) emissions.
ere is no single avenue to achieving these goals, but building these three pillars will
involve the adoption of appropriate, sustainable, highly productive, low risk, and low
GHG emission practices; building social and physical systems to help overcome the
eects of extreme climatic events; and developing policies and institutions to enable
these changes.
In previous sections we discussed how CA can increase agricultural productivity and
incomes. CA is the best opportunity we have at the moment to achieve the needed
technological changes in areas of eld crop production, and policy-makers in the
WANA region should consider CA systems as the best option for both adaptation to
climate change and mitigation of the causes of climate change, while at the same time
halting and reversing desertication. Concerns over global warming and rising food
prices are growing in WANA, and this should increase social and political support for
CA to help mitigate these eects.
Adaptation to climate change
CA will help farmers in the WANA region adapt to the warmer and drier conditions
provoked by climate change through improved soil quality and improved soil–water
dynamics (increased inltration rates, soil moisture storage, and crop water availabili-
ty; and reduced evaporation, runo, and erosion). Generally, CA has been shown to
give better resistance to dry spells and droughts and increased agro-ecosystem resil-
ience and stability (Figure 3). As mentioned above, crop yields are higher under CA,
especially under dry conditions, and less variable across years. is implies that farm
families will have more resilience to climate risks.
Figure 3. CA and climate change, adaptation, and mitigation features
Mitigation of climate change
GHG emissions are one of the principal causes of climate change, and carbon dioxide
(CO2) is one of the three principal GHGs. Plants capture CO2 from the air in photosyn-
thesis and convert it into plant tissue. When the plant dies, the tissue is converted into
soil organic matter. By increasing the levels of organic matter in the soil, CA manages
to ‘sequester’ CO2 from the atmosphere and store it in the soil, thus reducing the green-
house eect and climate change. Research in semi-arid Morocco has shown that CA
considerably reduced CO2 emissions compared to conventional tillage practices
(Moussadek et al., 2011). e amount of extra carbon stored in the soil is dependent on
climate regime (aridity), cropping intensity, biomass production levels, crop residue
return, and soil nutrient balance, as well as micro-meteorological properties at the
soil–plant interface. Most of these factors respond positively to CA systems.
In CA, fuel use is substantially reduced when tillage operations are eliminated, thus
reducing emissions of GHGs and other pollutants. Commonly, fuel use in CA systems
is 50–70% lower than in conventionally tilled systems.
Nitrogen oxides (especially nitrous oxide) are very potent GHGs and if nitrogen is
badly managed, nitrous oxide emissions can oset all of the benets of CA in increas-
ing carbon sequestration and reducing fuel use and emissions. It is therefore very
important to ensure that nitrogen is managed correctly and eciently. Nitrogen fertiliz-
ers should not be broadcast on the soil surface, but should rather be placed in a band
below the surface.
Difficulties with CA
e multiple benets of CA were outlined in the sections above. However, there are
also costs associated with the adoption of CA (Table 2). e rst of these is the cost of
learning about the new system and its management. Secondly, CA requires good and
precise management, and is more complicated to manage than a continuous cereal–fal-
low system with tillage.
Successful implementation of CA farming demands proper preparation, as well as
attention to detail and high-level management skills (Table 2). e farmer (and the
researcher and extension personnel) must acquire new knowledge, and be prepared to
adapt the system to their particular needs. It should be obvious that one cannot com-
pare a package of CA practices imported from elsewhere with the conventional practic-
es that have been developed, adapted, and adjusted over decades and expect the new
package to outperform the conventional practice without rst adjusting and adapting
the new practice.
Many of the benets of CA only develop in the longer term, whereas farmers need
short-term benets – farmers cannot aord to make short-term investments only for
the promise of long-term gain. It is important therefore to ensure that there are
short-term benets to the adoption of CA. is may need some incentives for
adoption. As noted above, many of the benets of CA are also public goods (e.g.
environmental conservation) as they benet other sections of society. is raises the
question for policy-makers of whether the farmer alone should bear all of the costs
associated with the conversion to CA.
Table 2. e two sides of CA systems
Benefits Trade-offs
• Reduced fuel costs
• Reduced labor requirements
• Reduced horsepower requirements
• Reduced equipment needs
• Increased crop yields under dry conditions
• Increased profitability
• Reduced soil erosion
• Increased water conservation and water
use efficiency
• Improved soil quality and soil health
• Carbon sequestration
• More sustainable agriculture
• Greater food security
• Climate change adaptation and
• Other environmental services
• Higher knowledge and managerial requirements
– difficult shift from conventional agriculture
• Competition for residues and balancing soil
quality with livestock feeding
• Costly necessary equipment
• Often a heavier reliance on herbicides
• Probable shifts in weed, pest and disease
populations and intensity
• Often higher nitrogen fertilizer requirements in
the first years
• Difficult in soils with poor drainage and excess
Competition for crop residues will be discussed later in this guide. However, balancing
the needs of the soil and the need for livestock feed is a major diculty in CA, especial-
ly in the early stages of adoption. e fact that farmers currently use the crop residues
means that there is a cost associated with leaving some of the residues on the soil
surface and this cost must be taken into account in analyzing the benets of the system.
Weeds are a major problem in any agricultural system, but tillage is an eective method
of weed control in conventional systems. Once tillage is stopped, weed control becomes
more dicult and, especially in the early years of CA, farmers may need to rely more
heavily on herbicides for early-season weed control. Also, as the change to CA involves
a change in the whole production system, it is likely that the change will benet some
weeds, pests, and diseases more than others, and there will be a shi in populations of
these organisms. Keeping ahead of these changes requires good management – includ-
ing monitoring of pest populations (including weeds, diseases, and insect pests),
acquiring information on their control, and initiating an eective integrated pest man-
agement (IPM) scheme on the farm.
ere is a cost associated with the increase in soil organic matter and soil fertility
under CA systems – in the initial stages of CA some more nitrogen oen needs to be
added to the system. is is because the crop residues (including roots) break down
more slowly in untilled situations and therefore also liberate the nitrogen they contain
more slowly. However, as pointed out later, this cost should be considered an invest-
ment – it is oen covered by yield benets in the short term in drier areas, and is more
than covered by the long-term benets of increased soil fertility.
As mentioned previously in this guide, CA provides many benets with respect to
water conservation and use. For this reason it is dicult to manage CA where soil
drainage and excess moisture are a problem and areas with poor drainage should be
avoided. ere are methods that enable the successful management of CA under these
conditions, including raised permanent beds, but again management of these systems
is more demanding and needs to be adapted and adjusted locally.
The principles of CA
e importance of not disturbing the soil
Only a few years ago all textbooks on agricultural production stressed that the aim of
land preparation was to prepare a seedbed that had a ne tilth. is tillage involved
turning the soil and breaking down aggregates and soil clods into loose, pulverized soil
into which it was very easy to seed.
Today we know that breaking down soil aggregates by tillage damages soil structure,
oxidizes soil organic matter (the organic matter that holds the aggregates together),
and ultimately leads to soil degradation.
Aer some years of tillage, soil organic matter levels in tilled soils are well below those
of untilled soils, and as organic matter is the most important component of soil fertility
and soil health, soils become far less fertile and require higher levels of fertilizer for
crop production. When roots and crop residues are mixed into the soil by tillage they
come in contact with oxygen and moisture and are broken down quickly. In an untilled
soil, however, oxygen enters the soil through the pores but is not as readily available to
organisms as in a recently tilled soil, and the rate of soil organic matter breakdown is
Tillage destroys root channels and other pores, and although it leaves considerable
pore spaces in the tilled soils, pores are not continuous and water does not ow
through them. In an untilled soil, channels from old roots, earthworms, and insect
burrows provide continuous pores that allow water and oxygen to enter the soil easily,
and which also facilitate root growth and exploration.
Tilling the soil also opens up the prole and facilitates the evaporation of water from
moist soil. e amount of moisture loss depends on environmental conditions and soil
moisture, but as much as 25 mm of moisture can be lost by conventional land prepara-
tion practices, whether these are with soil inversion or using a chisel plow.
As tractors plow the soil with a moldboard or disc plow, one wheel of the tractor is at
the bottom of the furrow and compacts the soil. Soil is also compacted by the tillage
implements themselves, forming plow pans at the depth where tillage is performed,
and restricting root growth and water percolation. In CA systems all wheel trac is on
the soil surface and there are no implements to cause compaction, except for seeding
tines and discs. Biological activity is increased because of the lack of tillage and also by
the availability of crop residues (see below), and the increased biological activity (espe-
cially of earthworms, insects, and similar organisms) helps restructure the soil and
break down any compaction formed by surface trac and seeders. A healthy,
well-structured soil is also able to resist compaction far better than a degraded soil.
However, it is important to restrict trac (including animal hooves) on CA elds
when they are wet – soil structure is weaker in wet soils.
Generally land preparation in conventional agriculture is carried out as soon as there
is some moisture from the rst rains, and then the crop is sown aer the next rains
when there is sucient soil moisture. In CA conditions, the crop can be sown straight
aer the rst rains, giving a longer growing season and higher yields as long as frost is
not a problem. If spring frosts limit early seeding of current varieties, longer season
varieties (usually higher yielding) which ower aer the frosts can be grown. In a
study using crop models, Sommer et al. (2012) found that under rainfed semi-arid
Mediterranean conditions there was a yield benet from earlier seeding in 25 out of 30
e importance of crop residues
e retention of crop residues is a key component of CA systems, and many of the
benets of CA come from the residues. Because crop residues are commonly used as
animal feed, farmers are oen reluctant to leave residues on the soil surface. However,
it is important to understand and demonstrate the benets of the residues (Figure 4)
so that the best balance between the needs for soil fertility and for animal feed can be
obtained. In some cases there may be benets to no-tillage even in the absence of appre-
ciable residue retention, as has been shown in the drier areas of Morocco (Oussama El
Gharras, personal communication), Iraq, and Syria (Haddad et al., 2014). However, it
is likely that there will be more benets to the system and to crop productivity
Figure 4. Soil conservation eects of crop residues under CA
if residues are le, and it is unlikely that systems without residue retention will be
Increased water inltration
Raindrops falling on bare soil break down surface aggregates, especially when these
have been pulverized and weakened by constant tillage over the years, and the loosened
soil particles run with the water and block the small pores that carry water down into
the soil. e surface layer of ne soil particles that is formed restricts the inltration of
water into the soil, and forms a crust when it dries that can impede crop germination
and require reseeding. Covering the soil surface, however, with crop residues protects
the soil surface from the explosive impact of the raindrops, so that surface pores
remain open and water inltration is maintained. is is an eect that can be observed
in the rst year of a CA system, provided sucient residues are le on the soil surface.
Obviously only the water that manages to enter the soil will be available for the crop
roots, and the rest of the water runs o the eld causing soil erosion and ooding.
Apart from the main eect of surface residues on water inltration through protecting
the soil surface from the eect of raindrops, the residues also slow the ow of water
across the soil surface as it runs o the eld, giving more time for the water to inltrate
into the soil. Slowing down the water also means that water does not erode the soil as
much, again reducing soil erosion.
In regions such as WANA where grazing of crop residues is the normal practice, it is
extremely dicult to maintain any crop residues on the soil surface, let alone achieve
complete soil cover. However, it is very important to leave some straw on the soil
surface both to protect it as much as possible from rainfall splash and to retain as much
moisture as possible from rainfall and run-on (water that runs onto the eld from
upper slopes). It is important to continue to demonstrate the benecial eects of crop
residues and work with farmers and livestock owners to identify avenues toward main-
tenance of some residues to enable system sustainability.
Reduced soil erosion
Soil erosion is caused by two natural forces – wind and water. Soil losses due to water
erosion in the WANA region are among the highest in the world, while wind erosion is
the major desertication process in the region. Reducing erosion, one of the principal
benets of CA, is therefore critical.
e soil that is lost to erosion is from the surface the most fertile part of the soil
prole. It is also the soil where seeds and fertilizers are placed, and with severe water
erosion these can be lost with early-season rains, requiring parts of the crop to be
reseeded and resulting in problems of soil fertility. Stopping, or greatly reducing, soil
erosion with CA halts the loss of fertile soil and over time reduces the amount of fertiliz-
er that needs to be applied to maintain soil fertility.
Crop residues and water erosion mitigation
Because surface residues increase water inltration into the soil, and slow the ow of
water across the soil surface, they greatly reduce soil erosion. Many studies have shown
that keeping approximately 30% of the surface covered with crop residues reduces
water erosion by about 80%. Full surface cover, which is extremely dicult to obtain,
generally stops water erosion completely.
CA allows the cultivation of steeper slopes than is possible under tillage-based
systems, but permanent contour bunds should still be maintained on these slopes to
protect against heavy rainfall events.
Crop residues and wind erosion reduction
Methods for preventing wind erosion from agricultural elds are limited to reducing
the wind speed. Crop residues can again help in reducing wind speed over the soil
surface and so reduce wind erosion. However, for best protection against wind erosion,
the residues should be le standing as stubble. e higher the stubble is cut at harvest,
the more eective it is in reducing wind erosion – for instance wheat straw cut at 30 cm
height will give twice as much protection against wind erosion as stubble cut at 5 cm
height. Although all methods of controlling wind erosion have their merits, including
trees planted as wind breaks, by far the most eective is leaving standing stubble on the
eld. Again, wind erosion is also reduced by doing away with tillage – loose, tilled soils
are easily eroded by wind.
Crop residues, evaporation, and soil temperature
Crop residues on the soil surface protect the soil from the sun’s radiation, and therefore
reduce the evaporation of water from the soil. is can oen be easily observed by
moving some of the residue cover in a CA eld – under the residues the soil is moist,
whereas the soil is dry where there is no ground cover.
Because the soil surface under crop residues is protected from radiation, it also
remains cooler, which is a benet not only for the germinating seeds and crop roots,
but also for the growth and diversity of the soil fauna and ora. However, soils may
remain colder longer into the spring in regions with cold winters, possibly delaying
seeding and early development of some crops.
Crop residues and water storage
As the residues increase water inltration and reduce evaporation there is more water
available for the crop in CA systems. is reduces the frequency and severity of
drought situations and results in higher yields in dry seasons and less risk of crop loss.
Also, over time, as soil organic matter increases, the amount of water that can be held
in the soil increases, reducing further the risks of dry periods. Large improvements in
the water storage in the soil prole have been found in semi-arid WANA regions under
CA systems.
Crop residues and the soil fauna and ora
Soil organisms are crucial to soil structure as they break the crop residues down into
humus which glues soil particles together, forming soil aggregates the key to soil
porosity, water-holding capacity, and soil quality in general. ese organisms, includ-
ing bacteria, fungi, insects, and earthworms depend on crop residues (both
aboveground residues and roots) for sustenance and survival. Under tilled systems
where the residues (including the roots) are mixed with moist, aerated soil during
tillage, they are broken down very rapidly by soil organisms, which then die o giving
the common ush’ of nitrogen 1–2 months aer tillage. However, in CA systems
where crop residues are le on the soil surface, they are broken down much more
slowly – generally only the portion of the residues in contact with the soil surface are
moist and ‘fed on’ by fauna and ora. Under CA situations there is not the large ush
of nitrogen seen in tilled situations (much of which is oen lost) but a slow, regular
supply of nitrogen, and the residues provide a constant source of food for soil organ-
isms. Due to the presence of a constant food source from the residues, it is common to
nd earthworms in a CA eld aer only a few years of a change to the new system – a
good indication that soil biological activity and soil health are improving.
Crop residues and soil organic matter
As discussed above, tillage breaks down soil organic matter and reduces soil fertility. In
a CA system, soil organic matter breakdown is much slower, and if enough residues
are le on the soil surface to complement the organic matter le by the roots, then soil
organic matter forms faster than it is broken down and organic matter levels increase
over time. is is the basis of the increase in soil fertility and productivity under CA:
soil organic matter is the key to soil structure (aggregation), chemical fertility (as it
holds nutrients in a form available to plants), and water relations.
e importance of crop rotation
One of the main reasons that crop rotation is especially important in CA systems is to
break the cycle of diseases that can survive on the residues of particular crops. How
oen a break is needed in the disease cycle depends on many factors including the envi-
ronment, the resistance level of the crop variety, how much residue remains, how fast
it decomposes under local conditions, and the characteristics of the particular disease.
In many cases it is possible to grow, for instance, a cereal crop for two or three consecu-
tive years before the levels of diseases harbored on the residues result in appreciable
and economic yield losses. en it becomes important to break the disease cycle
before seeding a cereal crop into the residues. Oen a break of one season will reduce
the disease levels suciently, but if the residues break down very slowly, then a break
of more than one season may be necessary.
Apart from the eect on diseases, crop rotation can also give many other benets,
some of which are still not fully understood. Incorporating a legume into a cereal
system can improve nitrogen nutrition, especially if the grain is not harvested (as
legume grain contains large amounts of nitrogen). ere are other possible benets,
including breaking the life cycle of insects that attack a particular crop, helping bring
nutrients from depth and deposit them in the residues at the soil surface by incorporat-
ing a deep-rooted crop in the rotation, and regulating ground cover by alternating
crops with durable residues (such as cereals) with crops whose residues break down
rapidly (such as legumes). Many crops also exude organic compounds from the roots
that help build soil structure and may also make some nutrients more available – for
instance some varieties of lupins can increase phosphorus availability in the soil.
In order to understand all of the eects of crop rotations, it is important to test dier-
ent options and observe the eects. However, markets need to be available for the
crops in the rotation, and the lack of markets can hamper the adoption of new crops
in the rotation.
Practical aspects of CA
Equipment for seeding into untilled soil.
CA requires dierent types of equipment from conventional agriculture. e farmer
no longer needs moldboard plows, chisels, disks, and harrows, but one basic require-
ment to establish a CA system is to be able to seed directly into untilled soil through
the crop residues. Although CA can be managed with dierent types of equipment,
including manual and animal-traction equipment, we will concentrate here on
tractor-drawn or -mounted equipment, as this is the most common equipment in the
WANA region.
Worldwide there have been many improvements in the design and durability of no-till
drills, and there is now considerable knowledge on the key requirements for a suitable
and versatile no-till seeder/planter.
Uniform and precise seed placement is a requisite for high crop yields. In CA this is
more dicult than in conventionally tilled elds because the soil is harder and the crop
residues can cause an uneven surface and, depending on conditions, may be dicult to
cut or penetrate. Also conditions are more variable than in conventionally tilled situa-
tions because of residue distribution that aects the degree of soil hardness. For preci-
sion placement of seed (and fertilizer) the residues must be uniformly spread to allow
the opening devices to cut through the plant material and place the seed at a uniform
depth. erefore, if appreciable amounts of straw are to be le on the eld, the combine
harvester needs to be tted with a straw spreader.
No-till planters/drills are heavier than conventional planters to enable them to pene-
trate untilled soil. ey must be able to cut through and/or move the residues, pene-
trate the soil to a depth suitable for proper rooting and growth, establish good
seed-to-soil contact and close the seeding furrow without gathering crop residues.
Keeping these ve points in mind, and the relative importance of each under the
particular conditions of the farm, a farmer can evaluate the strengths or weaknesses of
any piece of planting equipment, decide on the best model for his/her conditions and
make any adjustments or changes necessary to make no-till seeding successful.
Many dierent soil conditions can be present at the time of planting. Moist soils
covered with residues, which may also be wet, can dominate during late fall and early
spring. In contrast, hard and dry conditions may also prevail. Although cutting
residues is easier during dry conditions, it is more dicult to penetrate the hard, dry
soils. Proper timing, equipment selection and adjustment, and management can over-
come these dicult issues. e following paragraphs introduce the dierent types of
equipment to achieve these ends.
e major features of no-till drills (shown in Figure 5) are:
Figure 5. No-tillage seed drill components
Coulters are used to cut through surface residues and loosen some soil. ey can broad-
ly be classied on the basis of their diameter and the prole of their cutting edge. ere
are ve types of disk coulters: smooth (plain), notched, ripple, bubble, and wavy or
uted (Figure 6). Within this last group there are many congurations depending on
the number of waves and the width of the track. e rst four types of disks create
straight and narrow slots without much disturbance, whereas uted coulters create a
wavy or sinusoidal slot with greater disturbance. e amount of soil movement caused
by a particular coulter will depend on the planting speed. Fluted coulters, especially
those with relatively few large ‘waves, also require more weight.
Coulters are equipped with adjustable down-pressure springs to aid penetration and
cutting through the residues. e spring pressure is adjustable to allow the desired
degree of penetration to be obtained. Coulters should be adjusted so that they pene-
Figure 6. Major types of coulters
Drills equipped with coulters have less hair-pinning (forcing of uncut straw or cha
into the opener furrow) than drills with double disk openers alone because residue is
cut (and possibly mixed with soil depending on the type of coulter and the amount of
soil movement) ahead of the opener.
Furrow openers are used to open a slot in the soil and place the seed and the fertilizer.
According to the kind of opener used, no-tillage seeders can modify soil physical prop-
erties to dierent degrees depending on soil and climate conditions, thus potentially
aecting crop emergence and early growth (Table 3).
Soil-rming press wheels are devices used to close the seed furrow and rm the seed-
bed. Many sizes and congurations are available for most drills, from a narrow, single
press wheel to two wheels in a V-conguration (Figure 7).
In developing countries, CA equipment can be hard to nd, expensive, and/or not
suited to local conditions. Where possible, a farmer should rst try out dierent
Table 3. Advantages and disadvantages of openers (based on Mrabet, 2001)
Opener type (Figure 8) Disadvantages (weaknesses)Advantages (strengths)
V-shaped slot openers:(1 &
2 in Figure 8)
Openers can be double disk
(generally offset and/or of
unequal size), triple disk or
• Low maintenance
• Good residue handling
• Good depth control
• Low cost
• Better soil penetration requiring
less weight of the implement
• Deep penetration to moist
• Do not tuck residues into the slot,
but ‘brush’ them sideways
• Do not create smear surfaces at
the sides of moist planting
furrows, creating a better seedbed
• Simple and robust
• Compact (often used for small
grain seed drills)
• Good residue handling
U-shaped slot or furrow
Hoe or shank type
(3 in Figure 8)
U-shaped slot
Single disk
• Compaction and smearing of soil in wet
• Tend to ‘tuck’ residues into the slot
(hair-pinning) when residues are moist or
the soil surface is soft
• Seed implantation into hair-pinned
• Tend to concentrate seed and fertilizer at
the base of the slot if applied in the same
• High penetration force needed
• Difficulty in soil covering
• Wet and loose residues tend to pile up in
front of disks causing the drill to block
• High penetration force required
• Considerable soil movement (depending
on the angle)
• Problems with rocks and other obstacles
• Poor residue handling, bunching, and
increased residue covering
• Require a good cutting disk (coulter) for
long residues
• Considerable soil movement depending
on shape and width
• High wear rates
• Smearing in wet soils
• Inadequate depth control
Figure 7. Types of press wheels for no-tillage drills
machines, or closely observe the functioning of dierent seeders used by other farm-
ers, and preferably only purchase or procure a no-till planter aer testing the CA
system and acquiring a good knowledge of all components of the system.
e conformation of the most cost-eective and ecient drill may change over time.
For instance in WANA, if only small amounts of residues will remain on the eld, hoe
or shank type openers, even without a coulter to cut the residues, may be very ecient,
and cheaper than drills with disk openers. However, if the farmer later begins to leave
more residues, coulters or even disk openers may be more viable options.
For a long time, the major barrier to CA adoption in WANA was the availability and
suitability of direct-seeding equipment. In Morocco, Syria and Tunisia, research has
developed local, lower cost no-till seeders for small grain crops. However, more no-till
direct drill equipment adapted to local soil and crop conditions is still needed.
Crop management
It is important to remember that, to attain the potential from a CA system, all agronom-
ic factors (e.g. plant populations, seeding date, fertilizer practices, and varietal choice)
must be well managed, just as they need to be well managed in conventionally tilled
systems. In fact, other agronomic factors generally become even more important
under CA because the increased availability of moisture for the crop permits higher
yields, which therefore demand better management.
Cropping systems
Farmers generally have multiple goals aimed at maximizing the total economic produc-
tivity of the farm as a whole. Food, forage, and livestock production are all important.
ese objectives remain the same when a CA system is introduced, but may be more
complicated due to the dierent rotational crops that the farmer will manage on the
farm, together with the pest, disease, and weed control issues that these imply. Farmers
who start a CA system also need to maintain and manage the residues.
Crop rotation can itself bring management diculties to the farm, as the farmer must
learn how to manage, and importantly market, new crops. Until new markets can be
developed it is oen very dicult to increase the diversity of the cropping system.
However, where possible, CA cropping systems should include food legume, forage,
deep-rooted, and high-residue crops, as these will maximize the benets of crop
rotation. Avoiding monocropping (continuous cropping of the same crop) is essential
for achieving the agronomic and biophysical benets of CA. One of the early changes
in the conversion to a CA system in parts of the WANA region is to replace the
mixture. is gives the farmer more forage of a much higher quality than the common-
ly-practiced weedy fallow, and also begins the cycle of integrated weed management in
the system. However, it is also important to remember that managing rotations proper-
ly requires more skills than continuous cropping.
Sustainable weed management in CA
One of the main reasons for tilling the soil is to kill germinated weeds. As there is no
tillage in CA systems, dierent methods of weed control are needed. Achieving
adequate weed control is oen the biggest problem when a farmer starts a CA system
3@6 :7E:7 ?3K @776 FA GE7 :7D4;5;67E FA D7B>357 F:7 F;>>397 O @AD?3>>K 67E;553@F
herbicides that kill all germinated weeds but do not aect the crop seeds before they
are sown or germinate. ese herbicides, for instance glyphosate (the active ingredient
letting the crop emerge in weed-free conditions. However, in the semi-arid rainfed
areas of WANA, oen there are very few or no weeds present when the rst rains fall
and desiccant herbicide applications are generally not needed in these cases, as
experienced with CA on farms in Iraq and Syria (Haddad et al., 2014). Just as in
conventional (tillage-based) agriculture, weeds that germinate with or aer the crop
However, chemicals are not the only way to control weeds in CA systems, and it is
important that the farmer approaches weed management in an integrated manner,
employing several dierent methods of weed control. is is especially true because
continued use of the same chemical or family of chemicals can lead to populations of
weeds that are resistant to the herbicides and therefore are far more dicult to control.
e following paragraphs summarize the major components of integrated weed
Figure 8. Examples of some opener types shown in Table 3
Two of the major components of integrated weed management lack of tillage and
continuous ground cover – are also two of the pillars of CA. Tillage incorporates seed
into the soil, and then brings it up to near the surface the next season. However, in CA
systems any weed seed produced (and this should be very little in a well-managed
system) stays on the soil surface where it may rot, be eaten by birds and insects, or fail
to germinate due to unfavorable moisture conditions. In the CA system, seed that
remains deeper in the soil prole (incorporated by previous tillage and no longer
brought to the surface by more tillage) loses its viability over time and rots. At the same
time the crop residues or living plants shade the soil surface and inhibit seed germina-
tion – complete cover with a forage or green manure cover crop can drastically reduce
weed populations.
Crop rotation is another pillar of CA systems, and is also one of the components of
integrated weed management. is is largely because of the dierent selective herbi-
cides that are used in dierent crops, but also sometimes due to the heavy ground
cover of some crops in the rotation. One should remember that it is easier (and usually
cheaper) to control broadleaf weeds in a cereal crop and grass weeds in a broadleaf
crop. ere is also the possibility of allelopathic eects (where exudates from the crop
or the crop residues inhibit the germination and/or growth of other plants).
Stopping new weed seed from entering the eld is an important part of integrated
weed management. Practices for reducing or stopping new weed seeds from entering
the eld include:
Attention to detail, especially in the rst years, and spot-spraying and/or hand-pull-
ing weeds that have escaped control before they set seed. ere is an old saying
from European farmers of the Middle Ages that goes “One year’s seeding means
seven years weeding”: if the weeds are allowed to set seed it takes a long time (and
a lot of expense) to rid the eld of weeds again!
Keeping the edges of the eld clear of weeds either by grazing, cutting, or using
herbicides so that they do not set seed that can enter the eld again.
Taking care with grazing animals. Animals that have been grazing in weedy areas
can introduce a considerable amount of weed seeds into the eld. If possible try to
feed the animals on clean feed (hay from clean elds) for 4–5 days before they enter
the CA elds. Bedding and droppings from animals fed on weedy areas should be
composted to make sure the weed seed is killed before using it in the CA eld.
Making sure that equipment entering the eld is clean and does not contain weed
seeds. Good cleaning of seeders and any other equipment will reduce new infesta-
tions of weeds.
Finally, and very importantly, use good seed that is guaranteed to be free of weeds.
Using all of the components of integrated weed management will reduce weed pressure
over time – how fast this happens will depend on the type of weeds, the environment,
and how well the weeds are controlled and managed.
In summary the important components of integrated weed management in CA
systems include:
• Not incorporating weed seeds into the soil with tillage.
• Smothering germinating weeds with residues and/or crops, especially forage crops
or green manure cover crops.
Chemical weed control (herbicides) that may involve desiccant herbicides to kill
weeds that have germinated before seeding and/or selective herbicides to control
weeds that germinate with or aer the crop.
• Crop rotation with crops of dierent types so that herbicides are also dierent and
• Spot-spraying or hand-pulling weeds when populations are low so that they do not
set seed.
• Stopping new weed seeds from entering the eld through:
- Use of clean seeds;
- Use of clean equipment;
- Eliminating weed seed set in eld edges;
- Ensuring animals do not introduce weed seeds to CA elds.
Ecient application of herbicides
Achieving successful, economic, ecient, and environmentally friendly chemical weed
control is not easy and requires considerable knowledge. Some important aspects of
ecient chemical weed control are:
Choice of the right equipment (especially sprayers and spray nozzles) and their main-
• Calibration and correct management (spacing and height of application) of sprayers.
• Choice of herbicides taking into account the crop, residual eects, and crop rotation;
type, species, and age of weeds to be controlled; and herbicide families and their
rotation to limit the possibility of the development of herbicide-resistant weeds.
• Amounts and quality of water for dierent herbicides.
• Correct use of surfactants.
• Weather conditions for application, especially wind speed, relative humidity, and air
temperature, as well as soil moisture conditions. is knowledge is important both
to obtain ecient weed control and to limit damage to nearby crops through spray
dri and herbicide volatilization.
e importance and need for dierent herbicides and types of herbicides (Table 4) is
likely to vary over time, depending on seasonal climatic conditions and shis in weed
populations. In the semi-arid areas of WANA, and especially in cereal-based rotations,
post-emergence herbicides may be necessary to clean up weeds that escape the
pre-emergence desiccant herbicide. However, as reported by researchers from Syria
and Iraq, pre-emergence weed control can be sucient to control early-season weeds
and signicantly reduce weed infestations and pressure in CA. It is worth stressing that
it is important to invest time and eort in weed control in the early years of adoption
of a CA system to ensure that the weeds do not set seed.
Table 4. Herbicide application methods in CA systems: advantages and disadvantages
Application times
and products
Disadvantages (weaknesses)Advantages (strengths)
Pre-seeding/pre-emergence (of
the crop), non-selective
desiccants – only emerged
weeds are controlled
Post-emergence (of the crop),
selective herbicides with or
without residual effects
Pre-plant/pre-emergence (of
the crop), selective herbicides
with residual effects
• Weed control can be reduced by rain
within a few hours of application.
• Herbicide investment is made early in
the growing season.
• Potential for late-season weed pressure
in wet years although narrow crop rows reduce
this risk.
• Water quality important (glyphosate).
• Only required when weeds
germinate prior to seeding – burn-down
(desiccant) treatments at planting are not
required in many cases.
• Consistent weed control if properly
• Spraying at non-peak work
• No carryover effects (except on
exceptionally sandy soils).
• Low carrier volumes (glyphosate).
• Consistent weed control if properly done.
• Less time-sensitive (a larger application
window) than post-emergence programs.
• Less sensitive to short periods of adverse
• Broad-spectrum control available for some
• Reduced risk of carryover associated with
long residual compounds.
• Some herbicides with long residual effects may
not be desirable on land overlying shallow aquifers.
• Herbicide investment is made early in the growing
• Weed species that will be present must be
predicted in advance.
• A risk of carryover to subsequent crops in drier
years (depending on compound and crop sequence).
• Potential for late-season weed pressure in years
much wetter than normal, although split applications and
narrow crop rows reduce this risk.
• High carrier volumes.
• May not be effective where seeding equipment
causes substantial soil disturbance.
• Spraying decisions can be made
after weed pressure is known.
• Many post-emergence herbicides
have little or no soil residual effects.
• Can be used where residue
spreading has been less than ideal.
• Many compounds can be sprayed
with low rates of carrier.
• Active even where seeding
equipment causes substantial surface
• Burn-down treatment is usually required at planting time
with later seeded crops.
• Very timing sensitive (a narrow application window).
• Performance is sensitive to adverse environmental
conditions at or near spray time.
• Crop injury or poor control may result from inadequate
environmental conditions.
• Increased chance of cutworm problems due to early-season
weed growth in fields.
• Sequential treatments (two separate sprayings) may be
required to obtain broad-spectrum control.
• If failure occurs, few viable rescue alternatives are
• Yield loss to weed competition may occur prior to spraying.
Integrated pest (disease and insect) management (IPM)
Plant diseases can be divided into two main groups depending on the type of plant
tissue they can infect: some diseases can only infect living plant tissue (oen of a
particular species of plant or a group of similar species) and others can infect dead
plant tissue, and which oen infect tissue from a wider range of species. Leaf and stem
rust of wheat are two examples of the former – they are called obligate parasitic diseas-
es as they can only infect living tissue of wheat. Some other diseases such as Septoria
spp. or Alternaria spp. can infect living tissue, but they also survive on dead plant
tissue the crop residues. CA has no eect on the intensity of diseases of the rst
group but, as one of the components of CA is leaving crop residues on the soil surface,
it does aect the prevalence and intensity of diseases that survive on these residues.
Some of these diseases such as the leaf spotting diseases (tan spot and Septoria) and
head scab can cause problems in cereal systems with a switch to CA because of the
carryover of the diseases on the residues.
e best way to overcome disease problems is to use varieties that are resistant to the
common diseases. In most cases, including results from the WANA region (Piggin et
al., 2011), varieties that are good under conventional agriculture also perform well
under CA. However, this will depend on their resistance to diseases that survive on
crop residues – sucient resistance to these diseases may be a requisite for varieties to
be used in CA.
Populations of most insects that are harmful to crops are not aected either directly or
indirectly by tillage method. Almost all insect problems blamed on the maintenance of
residues can be traced to failures in sanitation or rotation practices. However, the
residue cover on CA elds appears to attract fewer aphids, which may then translate
into a lower incidence of barley yellow dwarf virus, which aects barley, wheat and
Just as with weeds, IPM programs can, and should, be implemented to successfully
manage insects and diseases in any cropping system – not just in CA. e principal
components of IPM are:
Crop rotation - the most important component of IPM in CA systems. Rotation
with a non-host crop is the single most valuable approach in helping to limit disease
and pest infestation in CA systems. Continuous cropping encourages infestation
and dominance of certain diseases and insects. Planting dierent crops breaks
disease and insect life-cycles and prevents them multiplying.
• Varieties with disease resistance.
• Correct planting dates to avoid or reduce disease incidence.
• Proper inter-crop and in-crop management to break disease and insect cycles, for
instance by controlling weeds to reduce insect populations.
• Finally, when absolutely necessary, the application of fungicides and insecticides.
Soil fertility management
Soil fertility management is a key component of ecient and protable crop produc-
tion. Under a CA system the new dynamics of moisture and organic matter result in
changes in nutrient availability and therefore require changes in the way nutrients and
fertilizers are managed. Soils generally contain abundant levels of many nutrients but
only small portions of these are in a form available to plants. Many nutrients (especial-
ly the micronutrients) are more available (are liberated more readily into the soil
solution) when associated with soil organic matter than in their inorganic form, and
so the increases in soil organic matter under CA enhance nutrient availability over
time. Also plants can only absorb nutrients in solution, and so absorption of nutrients
requires soil moisture, which is increased in CA systems as seen above.
If phosphorus is decient, farmers should apply and incorporate adequate amounts of
phosphorus fertilizer before the switch to a CA system. Banding of phosphorus fertiliz-
er is more ecient than broadcasting in a CA system, just as it is in conventionally
tilled systems. In fact, banding may be even more advantageous in CA because phos-
phorus movement in the soil is very slow and, as the soil is no longer plowed, a zone of
high phosphorus concentration is formed in the layer where fertilizer is applied.
CA also aects nitrogen management. Because of the increased surface moisture
under residues, maintaining crop residues can increase nitrogen losses due to volatili-
zation if fertilizers are broadcast. However, placing nitrogen fertilizer just below the
soil surface with a coulter can eectively reduce volatilization losses and increase nitro-
gen use eciency.
Building organic matter requires nitrogen as well as carbon. e organisms that break
down the crop residues (e.g. earthworms, microbes, and fungi, which comprise the
soil fauna and ora) need nitrogen as well as the carbon from crop residues and roots.
In turn they break down the residues into soil organic matter, make nutrients available
to plants, and build soil structure. Nitrogen may be temporarily tied-up by microorgan-
isms as they decompose crop residues. erefore, during the early phases of CA adop-
tion, when soil organic matter levels are increasing, more nitrogen may be required
than the crop uses. In most situations 10–20% more nitrogen should be applied during
the rst 3–5 years of the establishment of a CA system. Over time, the amount of nitro-
gen needed for CA should be similar to or even lower than that for conventional tillage
systems. e cost of this additional nitrogen should be considered as an investment as
it results in restored/increased soil fertility in the future, and is normally more than
oset by cost savings in tillage.
Aer several years of CA, the soil becomes more fertile and has higher levels of nitro-
gen, available phosphorus, potassium and many micronutrients. In many cases aer
the establishment of a good CA system, crop yields increase and fertilizer require-
ments go down.
Management of the crop residue cover
Because of all of their benets described above it is important that some crop residues
remain in the eld in CA systems. However, crop residues are also a vital source of
animal feed. Finding the balance between sustaining livestock and maintaining soil
fertility and productivity is something that each farmer will have to do. Initially it may
be dicult to keep much residue on the soil surface, but over time as crop productivity
(including straw production) increases, especially in drier areas, it should be possible
to leave more residues in the eld. It is also important that the farmer does not convert
his or her whole farm to CA in one step – but should start with a small part of the farm,
get to know the system and nd out how to manage it properly under local conditions,
before gradually expanding to cover the whole farm. is strategy also ensures that the
impact of the introduction of CA on the availability of livestock feed is minimized.
Research in dry areas has shown that aer a few years of CA, because of the increased
yields (of both grain and straw) under the CA system, as much feed can be removed
from CA elds as before (when they were tilled) but still leaving enough on the soil
surface to provide the benets of CA.
Crop residue must be properly managed year-round to provide the benets without
interfering with crop production. However, residue management is especially impor-
tant during harvest and seeding operations. At harvest the crop should be cut high
enough to leave standing stubble to control wind erosion, and the cut straw spread
evenly to ensure good soil cover and to allow ecient seeding – windrows of straw le
behind a combine harvester without a straw spreader make seeding very dicult and
the crop stand very variable the next season.
e residues from dierent crops break down (or, more correctly, are broken down by
soil fauna and ora) at dierent rates. is is associated with the requirements of the
fauna and ora for nitrogen as well as carbon – residues that are rich in nitrogen allow
the soil organisms to break them down faster than residues that have little nitrogen.
Cereal straw has little nitrogen (it has a high carbon:nitrogen (C:N) ratio – commonly
80:1 to 120:1) compared to legume residues which have a C:N ratio of approximately
20:1, and so cereal residues break down much slower than legume residues, which are
broken down very fast. erefore it is important to include in the rotation crops that
have durable residues, such as cereal crops, with legume crops, whose residues decom-
pose rapidly.
Livestock in CA systems
As mentioned earlier, the adoption of CA involves a trade-o between using crop
residues as animal feed and keeping them on the soil surface for water and fertility man-
agement. Livestock are generally an important part of the farming system and so the
need for feed cannot be disregarded. At the same time it is important to realize that
crop residues, especially the most common residues – those from cereal crops – have
low nutritional quality for livestock.
In the WANA countries, the integration of livestock and crops is not only a common
practice but is also a cultural and social norm, and it is important to respect traditional
rules governing livestock grazing in the region. Crop residues, and in particular cereal
stover, provide highly valued fodder for livestock. Changing social norms requires
negotiation and the involvement of all stakeholders, including local policy-makers,
and is one of the prime topics for discussion and resolution by the local innovation
platform that will be discussed later in this guide.
At the same time, ground cover holds the key not only to successful CA systems but
also to sustainable agriculture – systems where organic matter decline and soil erosion
continue unabated are not sustainable, and so, even though the trade-o between
livestock feed and ground cover will be dicult to resolve, it is necessary to achieve
sustainable farming systems. Several options to facilitate the co-evolution of CA and
livestock are outlined below, but the particular options and mix of options that are feasi-
ble will depend on local conditions and the particular farmer’s needs. ese options
include (Mrabet, 2008):
• Replacement of the (weedy) fallow with fodder crops to produce a greater quantity
of higher quality feed for livestock;
• Introduction of forage legumes (i.e. vetch and sulla) and cereal/legume mixes (e.g.
vetch/oats or pea/triticale) in the cropping systems. Legumes are an important
source of high-quality feed for animals, for nitrogen cycling, and as a weed and
disease break in cereal monoculture;
• Partial removal of crop residues, ensuring that enough residues are le for soil
protection and enrichment;
• Flexible seasonal controlled grazing on stubble with appropriate stocking rates;
• Establishment of perennial forages for direct grazing and for cut-and-carry (use of
fodder trees, shrubs, and cactus);
• Introduction of row crops (cash crops) for generating higher returns to guarantee
feed purchase, especially if supplementary irrigation is possible;
• Use of silage and feed blocks to give more ecient use of a wide range of agro-indus-
trial by-products;
• Temporary displacement of animals to pastures; soil physical condition of degraded
lands may recover faster under CA conditions when animals are excluded for a
• Increasing crop biomass yields and soil quality through integrated soil fertility
management and best management practices. Combined with the partial removal
of crop residues this can increase straw availability for livestock while safeguarding
soil quality;
• Production of better quality (more nutritious) straw through genetic improvements.
In other regions of the world, integrated crop/livestock farming is successfully man-
aged under a CA system and so there is no reason why this cannot be achieved in the
WANA region. However, it will not be easy because cultural norms are deeply
ingrained, and only with education and understanding of the perils of unsustainable
agricultural practices and the involvement of all stakeholders will sustainable
solutions be developed.
Top ten practical factors for CA adoption
It can be dicult to fully switch to CA. Farmers should rst identify and experiment
with CA in situations where it is likely to have the highest impact and hence accepta-
bility. For CA to be widely accepted and for farmers to be successful in their adoption
of CA farming systems, each one of the following ten points (based on Derpsch, 2008)
must be addressed through careful planning prior to starting with the CA system. e
farmer should:
1) Improve his/her knowledge of the system especially concerning weed control –
and plan for the change to permanent CA at least one year in advance.
2) Analyze the soil and aim for a balanced nutrient status and adequate pH.
3) Avoid soils with poor drainage.
4) Eliminate soil compaction (plow pans) before starting with the CA system.
5) Flatten out irregularities in the soil surface to enable uniform seeding.
6) Produce the largest possible amount of mulch cover.
7) Obtain the use of a no-till seeding machine.
8) Start small: start on 10% of the farm.
9) Use crop rotation, possibly including green manure cover crops.
10) Be prepared to learn constantly and watch for new developments.
CA: lessons learned from other countries
CA systems have been developed and adopted in many countries around the world
over the last half-century. Lessons learned from a wide range of diverse agricultural
systems, soil types, climatic conditions (including tropical, sub-tropical, and temper-
ate climates), and farm sizes provide a wealth of information to help in developing CA
systems in new areas. CA systems are practiced by at least some farmers in most coun-
tries around the world, and the system has been adopted on over 125 million hectares
worldwide, equivalent to 9% of the world’s cropped lands. e countries with the great-
est areas of CA are the USA (26.5 million hectares), Brazil (25.5 million hectares),
Argentina (25.6 million hectares), Australia (17.0 million hectares) and Canada (13.5
million hectares) (Kassam et al., 2012). Recently there has been a large expansion of
the CA area in Kazakhstan, China, and several countries in eastern and southern
Africa. Although zero-tillage wheat production has expanded rapidly in South Asia
over the last 15 years, the wheat crop is generally alternated with an intensively tilled
rice crop and therefore cannot be regarded as a true CA system. However, recent
advances in direct seeding or direct transplanting of rice into untilled soil suggest that
a CA revolution is likely in South Asia over the next decade.
In general the spread of CA in the Americas and Australia has been farmer-driven,
with dierent degrees of support from research and extension systems. Soil erosion,
soil degradation, the need for ecient use of water, especially rainfall, and rising costs
of production have been the major drivers behind the expansion of CA. Many of these
experiences are relevant to the WANA region.
CA has spread most rapidly where agriculture is not subsidized by the government; in
Latin America the area under CA has increased from only a few thousand hectares in
1990 to over 50 million hectares in 2008 (Derpsch and Friedrich, 2011; Kassam et al.,
2012). Although most of this area is on relatively large, mechanized farms, there are
also thousands of smallholder farmers practicing CA using animal traction and/or
manual equipment. Results from China and sub-Saharan Africa (as well as for wheat
in South Asia) have also shown that CA systems can be protable for smallholder and
resource-poor farmers.
In Europe, CA has progressed relatively slowly, possibly due to the level of subsidies.
Today CA is found mainly in Russia (3.1 million hectares) and Spain (0.6 million
hectares). It is promoted in France, Finland, Ireland, Italy, Portugal, and the UK. It is
however important to note that CA is progressing more rapidly under perennial than
annual crops in Spain, France, and Italy. e EU experience in applying CA systems in
fruit orchards, vineyards, and olive plantations could be useful in the WANA region
where olive and fruit value-chains require improved quality for greater competitive-
ness. In studies in Lebanon, savings due to CA over a three-year period in olive planta-
tions were US$2000/ha (Jouni and Adada, 2010).
It is interesting to note that 72 million hectares of CA are located in Mediterrane-
an-type climates (i.e. South and North America, Australia, and South Africa). e
climate of Australia, with its pronounced aridity and frequent drought, is especially
relevant to most WANA countries. Reduced soil disturbance through no-till and
conservation farming methods have led to large increases in protability and sustaina-
bility in the Australian cropping belt. e adoption of CA by farmers in Australia
varies from 24% in northern New South Wales to 42% in South Australia and over
90% in Western Australia.
Ekboir (2002) studied the adoption of no-tillage and CA in six countries (Brazil, Para-
guay, Bolivia, Mexico, India, and Ghana) and found that “although the development
of no-till packages and their adoption by small-scale farmers followed dierent paths
than for large-scale farmers, the paths shared one important common feature: all
successful programs resulted from networks that worked with participatory research
State of CA in WANA
CA is applied on roughly 39,000 hectares in West Asia (Table 5) where spontaneous
adoption of CA has been catalyzed by fuel shortages and two Australian-funded
projects, which resulted in increased availability of locally produced aordable no-till
seeders now being exported to other WANA countries (e.g. Maghreb countries)
(Haddad et al., 2014). Although CA research started in the early 1980s, adoption of
CA in the Maghreb countries, where CA oers multiple benets to farmers, is still
lagging behind other regions (Boulal et al., 2014).
Table 5. Area of CA systems in selected WANA countries in 2011. Data from Haddad et al. (2014),
Kassam et al. (2012) and Boulal et al. (2014)
Country Area (ha)
Syria Arab Republic
For a durable, continuous shi from conventional agriculture to CA in WANA, the
change in paradigms needs commitment and changes in behavior of all concerned
stakeholders. In fact, CA researchers, extension agents, and farmers need to motivate
policy-makers, institutional leaders, politicians, donors, and international agencies to
assist in removing external constraints and creating an environment in which CA
systems can ourish. In many cases it is not a case of creating subsidies to promote CA,
but rather removing policies that hinder the adoption of sustainable practices for
instance subsidies on tillage equipment.
Improving the quality of information exchange among farmers, research institutions,
universities, agribusinesses, and government agencies will no doubt go a long way
toward overcoming obstacles and trade-os (Table 6). Farmer-to-farmer information
and knowledge exchange has been shown to be the most eective route for technology
adoption and it is important that extension systems support and facilitate farmer
knowledge communication. Field days in which farmers are the presenters and protag-
onists are far more eective in convincing other farmers that a technology is worth-
while than presentations by researchers and extension agents.
Critical factors in promoting CA adoption in WANA
Adoption of CA requires solid local adaptive research, persistence in discovering the
reasons behind failures, and belief in making the CA principles work. CA is a complex
production system involving many components that must be adapted to local condi-
tions and farmer needs. For this sort of technology the old linear model of agricultural
knowledge ow – where researchers develop technologies and transfer these to exten-
sion agents who then transfer them to farmers – does not work. Farmer feedback and
participation in the technology development and adaptation is vital.
Where possible, farmers should also take the lead in the extension process, with farm-
er-to-farmer exchange facilitated by both extension agents and researchers. However,
as noted earlier, achieving widespread adoption of CA in WANA will require more
than the development of viable technological options – it will also need considerable
eorts to remove bottlenecks in the complete value chain, where bottlenecks are oen
more institutional (e.g. markets and policies) than technological. To address both the
Table 6. Risks in CA systems
Type of risk ExplanationCause
Biological Switching to CA may cause a shift in the makeup of pest populations.
A few harmful insects are indirectly affected by tillage in terms of how it impacts the habitat they
need for survival. Undisturbed residue may provide a better habitat for the
over-wintering/over-summering life stages to survive (e.g. Hessian fly). However they also provide
a habitat for beneficial insects and pest predators.
Nutrient stress
Usually an increase in disease incidence and/or severity of some diseases may occur because a
greater quantity of inoculum of the pathogen is present on the residues left above the soil surface,
especially when an adequate crop rotation is not employed.
Allelopathic exudates from decaying residues within the seed slot reduce early seedling vigor and
may kill them. This can sometimes explain no-tillage failure with double-disk type drills.
Nitrogen may be temporarily tied-up by microorganisms as they decompose crop residue with a
high C:N ratio. Placement of fertilizers should be far enough from seeds to avoid toxicity problems.
Physiological stress In no-till conditions in wetter areas, moist soils with high mulch levels may cause waterlogging
and/or reduce soil temperatures, prejudicing germination and early crop growth.
Inefficient fertilizer
Cost of initiating CA
There are two risks from inappropriate fertilizer placement at sowing: a) If fertilizer is banded with
seeds, there is a danger of damage or burning of the seeds; and b) if fertilizer is broadcast, the
crop may suffer from uneven fertilizer distribution and nutrient losses.
Changing from conventional farming to CA requires investment in equipment, tools, and
agro-chemicals, which is often a constraint for poor farmers. Initially input investments may not be
compensated for by reduced tillage costs.
To recover the cost of no-till machines requires an increase in crop yields and/or a reduction in
costs of production.
Weed control
No-tillage systems favor crop productivity under more extreme and variable weather events than
conventional tillage systems. However, CA is riskier in soils with limited drainage in periods of
excessive rainfall.
Poor calibration and/or malfunction of seeders are major risks for successfully implementing CA
(and conventional agriculture).
Ineffective herbicide weed control will increase the risk of impaired crop performance.
Machine function
Machine impacts
on crop yields
For a durable, continuous shi from conventional agriculture to CA in WANA, the
change in paradigms needs commitment and changes in behavior of all concerned
stakeholders. In fact, CA researchers, extension agents, and farmers need to motivate
policy-makers, institutional leaders, politicians, donors, and international agencies to
assist in removing external constraints and creating an environment in which CA
systems can ourish. In many cases it is not a case of creating subsidies to promote CA,
but rather removing policies that hinder the adoption of sustainable practices for
instance subsidies on tillage equipment.
Improving the quality of information exchange among farmers, research institutions,
universities, agribusinesses, and government agencies will no doubt go a long way
toward overcoming obstacles and trade-os (Table 6). Farmer-to-farmer information
and knowledge exchange has been shown to be the most eective route for technology
adoption and it is important that extension systems support and facilitate farmer
knowledge communication. Field days in which farmers are the presenters and protag-
onists are far more eective in convincing other farmers that a technology is worth-
while than presentations by researchers and extension agents.
technical and institutional aspects of CA adoption, innovation platforms have been
shown to be extremely important.
e innovation platform
e development of innovation platforms is one of the keys to the success of complex,
multi-component technologies such as CA. An innovation platform involves a
network of dierent agents and institutions working together and sharing information,
to overcome bottlenecks in the production system. e platform will include farmers
and as many of the key stakeholders in the principal local agricultural value-chains as
possible: researchers, extension agents, machinery manufacturers, input and service
providers, output market agents and intermediaries, credit providers, and policy-mak-
ers all participating in the development and testing of dierent aspects of the develop-
ment process. It is important that all members of the platform stand to gain from
increases in agricultural production and productivity. Some members of the platform
will be doing the actual development, with others providing feedback on the perfor-
mance of the innovation and its interaction with other components of the package. For
example, machinery manufacturers or agrochemical company representatives can
oen provide solutions to equipment or weed problems that may not be evident to a
network comprising only farmers and research and extension agronomists, and which
would take limited networks considerable time to develop.
Small networks can generate valuable knowledge and technologies, but will be less
ecient if important agents are absent. At the same time, if some important agents are
not willing or able to participate, the network can still develop and function, although
not as eciently. It is more important to develop a functioning network of interested
stakeholders than to expend considerable eort trying to incorporate uninterested
Innovation platforms do not simply form by themselves. Normally it is dicult to get
all the necessary players to talk to each other and become involved in trying to analyze
and overcome bottlenecks to agricultural production and productivity (including,
importantly, economic productivity). Energetic catalyzers who are convinced of the
importance of CA and sustainable agricultural production systems are needed to push
and encourage all of the dierent agents to participate in the innovation platform.
Oen, once platform members see the benets they obtain from involvement they
become far more enthusiastic about continued participation. In the past, catalyzers
have come from local research and extension systems, international agencies, and even
agrochemical companies. However, the role of leader, instigator, and catalyzer of the
local innovation platforms is one that normally ts well with extension agents and
researchers, and they should be encouraged and supported in eorts to develop and
maintain local platforms.
e change from the linear model of information ow to that of an innovation
platform implies important changes in the way researchers and extension agents func-
tion and interact with farmers. Extension agents need to be equipped with appropriate
information for farmer empowerment and become, primarily, facilitators of farm-
er-to-farmer knowledge exchange instead of technology transfer agents. Researchers,
however, should be involved in the innovation platform and learn from farmers of
their needs and their perceptions of technology shortcomings. Researchers should
concentrate on developing practical solutions to problems encountered with CA on
farmers’ elds rather than concentrating on comparing tillage systems.
To convert from conventional and traditional systems to CA is not a simple technical
process, but rather one that requires a major simultaneous change in the mind-set of
farmers, extension agents, researchers, technicians, and decision makers. It is therefore
necessary to adopt a systems approach and get all stakeholders involved in an innova-
tion platform focused on CA. In addition, joint resource mobilization is essential.
Strengthened extension and focused and reliable subsidy programs will help CA
progress in WANA. It should be obvious that these changes will not be easy, and there
are likely to be many problems and pitfalls on the road to widespread adoption of CA
in the region. However, the alternative of continuing along the present road of soil
erosion, degradation, and unsustainability is socially unacceptable, and society owes it
to future generations to leave the land and the environment in a better state than that
which we inherited.
Boulal, H., M. El Mourid, H. Ketata and A. Nefzaoui. 2014. Conservation agriculture
in North Africa. Pages 293–310 in Conservation Agriculture: Global Prospects and
Challenges (R.A. Jat, K.L. Sahrawat and A.H. Kassam, ed.). CABI, Wallingford, UK.
Derpsch, R. 2008. Critical steps to no-till adoption. Pages 479–495. In: No-till farming
systems, T. Goddard, M. Zoebisch, Y. Gan, W. Ellis, A. Watson, and S. Sombatpanit
(ed.), Bangkok:World Association of Soil and Water Conservation (WASWC), p
Derpsch, R., C.H. Roth, N. Sidiras and U. Köpke. 1991. Controle da erosão no Paraná,
Brasil: Sistemas de cobertura do solo, plantio direto e preparo conservacionista do
solo. Deutsche Gesellscha für Technische Zusammenarbeit (GTZ) GmbH, Eschborn,
Derpsch R. and T. Friedrich. 2011. CA Adoption Worldwide. FAO-CA website
available online at: (
Ekboir J. 2002. Part 1. Developing no-till packages for small farmers. Pages 1–38 in
CIMMYT 2000-2001 World Wheat Overview and Outlook: Developing No-Till
Packages for Small-Scale Farmers (J. Ekboir ed.). CIMMYT, Mexico.
FAO. 2002. e Conservation Agriculture Working Group Activities 2000–2001. FAO,
Haddad, N., C. Piggin, A. Haddad and Y. Khalil. 2014. Conservation agriculture in
West Asia. Pages 248–262 in Conservation Agriculture: Global Prospects and
Challenges (R.A. Jat, K.L. Sahrawat and A.H. Kassam ed.). CABI, Wallingford, UK.
IAASTD (2008) Agriculture at a Crossroads: e Synthesis Report. Washington, DC,
USA: International Assessment of Agricultural Knowledge, Science and Technology
for Development., K. and F. Adada. 2010. Conservation
agriculture in olive orchards in Lebanon. In Poster Presentation, 4th Mediterranean
Meeting on Conservation Agriculture. Setif, Algeria. Options Méditerranéennes, A no.
96, IV Rencontres Méditerranéennes du Semis Direct.
Kassam, A., T. Friedrich, R. Derpsch, R. Lahmar, R. Mrabet, G. Basch, E.J.
González-Sánchez and R. Serraj. 2012. Conservation agriculture in the dry
Mediterranean climate. Field Crops Research 132: 7–17.
Moussadek, R., R. Mrabet, R. Dahan, A. Douaik, A. Verdoodt, E. Van Ranst and M.
Corbeels. 2011. Eect of tillage practices on the soil carbon dioxide ux during fall and
spring seasons in a Mediterranean Vertisol. Journal of Soil Science and Environmental
Management 2(11): 362–369.
Mrabet, R. 2011. No-tillage agriculture in West Asia & North Africa. Pages 1015–1042
in Rainfed Farming Systems (P.G. Tow, I.M. Cooper, I. Partridge and C.J. Birch ed.).
Springer, Dordrecht, Netherlands.
Mrabet, R. 2008. No-tillage systems for sustainable dryland agriculture in Morocco.
INRA. Rabat, Morocco.
Mrabet, R. 2001. Le Semis Direct: Une technologie avancée pour une Agriculture
durable au Maroc. Bulletin de Transfert de Technologie en Agriculture MADR-DERD.
Nº 76.
Pieri, C., G. Evers, J. Landers, P. O'Connell and E. Terry. 2002. No-Till farming for
sustainable rural development. Agriculture and Rural Development Working Paper.
IBRD Rural Development Department, Washington.
Piggin, D.C C., A. Haddad and Y. Khalil. 2011. Development and promotion of zero
tillage in Iraq and Syria. Pages 304–305 in Proceedings of the 5th World Congress on
Conservation Agriculture, Australian Centre for International Agricultural Research,
Brisbane, Australia. Available at: (Powerpoint
presentations used during the oral presentations and for workshops) (accessed
November 12, 2014).
Piggin, D. C. and M. Devlin. 2012. Conservation agriculture: opportunities for
intensifying farming and environmental conservation. Research to action: 2. ICARDA,
Aleppo, Syria.
Sommer, R., C. Piggin, A. Haddad, A. Hajdibo, P. Hayek and Y. Khalil. 2012. Simulating
the eects of zero tillage and crop residue retention on water relations and yield of
wheat under rainfed semiarid Mediterranean conditions. Field Crops Research 132:
... Furthermore, the NT seeder needs to have a separate placement of seed and fertilizer in the furrow to avoid toxicity problems for germinating seedlings and to guarantee the vigor and early growth. CA can be managed with different types of equipment, including manual, animal-traction, and tractor-drawn or -mounted equipment (Mrabet and Wall, 2015). The choice of suitableNT seeder not only depends on the soil type and amount of residue present in the field but also on the geographic and social conditions. ...
... The crop residues on the soil surface protect the soil from the sun's radiation, and therefore help in soil moisture conservation due to reduced soil surface evaporation and improved rainfall infiltration, specially under dry or moisture-limited conditions in the MENA region (Mrabet, 1997;Mrabet and Wall, 2015). This reduces the frequency and severity of drought situations and results in higher yields and less risk of crop loss in dry seasons. ...
Soil health assessment tools are needed to quantify effectiveness of various agricultural practices toward meeting sustainable development goals. Although several soil health tools have been developed and tested through global soil management research, ease of use and site-specific accuracy for farmers and agronomists needs to be optimized. This comprehensive review examines the theories, compares approaches, and examines applications of five soil health assessment methods, and then compares their advantages, disadvantages, application limitations, and feasibility before suggesting potential improvements at various scales. The two predominant soil health assessment tools [Soil Management Assessment Framework (SMAF) and Cornell's Comprehensive Assessment of Soil Health (CASH)] were coupled with six classical mathematical models [Principal Component Analysis, Analytic Hierarchy Process, Iterative Algorithm, Entropy weight method, Euclidean distance and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS)] to create 11 approaches that were compared using field-based soil health indicator measurements. The data were collected from field experiments with cover crops and soil amendments in Mississippi, USA. The Standard Scoring Functions (SSF) associated with the SMAF and the CASH tools were evaluated. Our results, reflecting different data normalization and weighting, created 14 different soil health scores that showed significant differences based on method. Among the three data normalization methods (CASH, SSF, and entropy weighting), soil health scores using SSF were relatively high, while those using entropy weighting were much lower. The latter method, TOPSIS, had the advantage of being able to maximize differences among treatments and thus can help select an optimal management solution. Scores obtained through SSF, SSF + PCA and SSF + AHP had some of the best correlations) with corn (Zea mays L.) and soybean [Glycine max (Merr.) L.] yields, indicating the SSF parameters selected for our study were applicable. CASH provided similar results with a more simplistic approach. Other methods generated soil health scores with poorer fits when compared to the yield data. Overall, we conclude all 11 methods and 14 soil health scores can be useful for soil health evaluation in the study area. The results re-emphasized that soil health assessment is useful for soil researchers, farmers, and any other stakeholder group wanting to determine if specific agricultural practices contribute to sustainable development.
... Furthermore, the NT seeder needs to have a separate placement of seed and fertilizer in the furrow to avoid toxicity problems for germinating seedlings and to guarantee the vigor and early growth. CA can be managed with different types of equipment, including manual, animal-traction, and tractor-drawn or -mounted equipment (Mrabet and Wall, 2015). The choice of suitableNT seeder not only depends on the soil type and amount of residue present in the field but also on the geographic and social conditions. ...
... The crop residues on the soil surface protect the soil from the sun's radiation, and therefore help in soil moisture conservation due to reduced soil surface evaporation and improved rainfall infiltration, specially under dry or moisture-limited conditions in the MENA region (Mrabet, 1997;Mrabet and Wall, 2015). This reduces the frequency and severity of drought situations and results in higher yields and less risk of crop loss in dry seasons. ...
Full-text available
Conventional tillage coupled with monocropping and limited recycling of crop residues along with increased pressure from human and livestock population has led to the degradation of the soil, water resources, and the environment in the Middle East and North Africa (MENA). Conservation Agriculture (CA) considered as “climate-smart” agriculture, strives to achieve acceptable profits along with high and sustained production levels while concurrently conserving and regenerating soils and protecting the environment. The objectives of this paper are to review and synthesize available findings on CA, its past trends, current opportunities and challenges, evidence on potential benefits from its adaptation, to discuss its future outlook, and to make relevant recommendations for interventions and novel research needs for its wider diffusion in the region. In MENA, major research on CA has been mainly conducted in Morocco, Tunisia, Iran, and Syria, while Jordan, Lebanon, Iraq, Egypt embarked CA research fairly recently. About 25–40% out of the 53 million hectares total arable land is estimated to be suitable for CA in the region. In recent years a growing number of studies carried under a range of climatic, soil, management and cropping conditions in many countries of MENA reported several benefits including higher and more stable yields and profits, reduced risks of crop loss, labor requirements, soil erosion, and improved soil moisture and quality under CA system. Despite its benefits, adoption of CA in MENA is still very low for various reasons including: lack of affordable and well-adapted seeders, the complexity of the CA system which posed a major challenge for mostly uneducated farmers to comprehend, ill-conceived policies that promote cereal intensification hence inadvertently promote monocropping, tradeoffs between residue retention and livestock feed, lack of adequate policy and institutional framework and incentives to enhance farmers’ adoption, and the private sector's active involvement in the dissemination of CA. The wider acceptance of CA requires the development of affordable and versatile no-till seeder alongside the implementation of integrated crop management practices. CA-based bundled agronomic management practices must be tailored to the biophysical and socio-economic environment. Finally, effective strategies for upscaling CA in MENA has to be developed by taking into consideration the unique features of the region. Despite the daunting past adoption trends and current challenges, we predict a bright future for CA in the region due to several factors including: rising energy prices and wage rates, the emergence of younger and more educated farmers, the advent of climate change, the increasing awareness on the degradation of land and water resources among farmers and policy makers, changes in dietary preferences subsequently increasing trends in demand and prices of legumes are expected to increase the desirability of CA and enhance its wider diffusion in MENA.
... It can also make the soil more susceptible to losses of OM through increased erosion (both wind and water). Therefore, the adoption of reduced tillage or no-till (direct seeding), with the maintenance of significant surface residues, is a measure that is advocated to contribute significantly to reducing the rapid decomposition of SOM in drylands, while offering other favorable conditions for crop growth, such as improved soil moisture conditions and soil fertility status (Moussadek et al. 2011;Mrabet 2012;Bayala et al. 2012;Mrabet and Wall 2015). ...
Full-text available
INTRODUCTION: By definition, drylands include arid, semi-arid and dry sub-humid zones. In the continent of Africa, drylands represent about 43% of the total surface area and cover more than 70% of agricultural land. About 50% of the African population lives in these areas and is significantly fragile in terms of food insecurity. Climate change, which is expected to increase the frequency and severity of extreme weather events, will exacerbate the vulnerability of these lands if effective adaptation and resilience action is not undertaken. The livelihoods of most dryland populations depend on natural resource- based activities, such as agriculture and livestock. Forced to meet urgent short-term needs, house- holds resort to unsustainable practices, resulting in strong pressure on the natural resources, loss of biodiversity and severe soil degradation. One of the crucial factors considered as a cause and a con- sequence of agroecosystem vulnerability in dry areas is soil degradation (Biancalani et al. 2015). Various interacting processes of such degradation include water and wind erosion, salinization and loss of soil fertility, mainly the decrease of its organic matter (OM) content. These processes lead to a decline of the soil health and productivity, as well as its capacity to contribute to the reduction of carbon (C) emissions into the atmosphere. Studies on the understanding of the dynamics of soil organic matter (SOM) in different soil and climate contexts of the world have been extensively addressed, and their scientific bases remain current (Hénin and Depuis 1945; Hénin et al. 1959; Jenny 1941; Laudelout 1993; Bremer et al. 1995; Janzen et al. 1997). Hénin and Dupuis (1945) developed, for the first time, balance equa- tions for SOM decomposition. Hénin and Monnier (1959) addressed the physical and biochemical determinants of the dynamics of SOM, and Laudelout et al. (1960) established quantitative relations between the content of SOM and climate. These and many other research studies were motivated by the need to understand soil genesis, to improve soil properties and productivity, and to elucidate the interrelationships among plant nutrition and C and nitrogen (N) biogeochemical cycles (Campbell et al. 1984). Studies included laboratory and field experiments involving long-term trials and mod- eling approaches. More recently, Campbell and Keith (2015) conducted a fairly comprehensive lit- erature review on developments in SOM modeling. The current concerns related to climate change drive the interest to mitigate greenhouse gases (GHG) and adaptation to climate change in soils, more precisely through soil organic carbon (SOC) sequestration (Lal 2004). This chapter discusses the status of SOC in the dryland agricultural soils of Africa and looks at some of the underlying issues, which remain relevant despite the abundant literature on this topic.
Technical Report
Full-text available
Agricultural water presents a set of challenges and opportunities for Arab countries as they work towards sustainable development. While water scarcity and variability in the region have been known and addressed for centuries, accelerating pressures from a range of drivers, including urbanisation, forced displacement and climate change, mean that water poses a growing threat to sustainable development and stability. At the same time, the Arab region has a unique opportunity to harness emerging innovations and financing mechanisms to address water-related challenges. Unless action is taken, Arab countries may miss out on opportunities for economic development and face the impacts on people’s well-being and social stability. To make agricultural water work for sustainable development, food security and poverty reduction, these countries need to focus on emerging opportunities and innovations to create momentum for policies and investments and sustain it over time. A new generation of policies and investments is needed to face these challenges, transform the agriculture sector and accelerate progress towards sustainable development.
Full-text available
Over time, the interdependence between agriculture and environment is becoming both complex and obvious. Land mis-management through excessive or inappropriate tillage practices, over-grazing and biomass exportation for livestock feeding are harming and mining natural resources. In other words, there is a drastic large scale soil degradation where erosion, organic matter depletion and compaction processes are the most important environmental problems. The increasing Moroccan population, coupled with water and land scarcity, put increasing demands on agricultural scientists to increase crop yields in environments in which water deficits prevail. The twentieth century saw the Moroccan economy relying heavily on agriculture and agricultural export. The overriding challenge facing Moroccan agriculture is the need to increase production of food enough to feed ever-growing population. Achievement of food security is of paramount importance. The question arises as to whether agriculture can in fact reasonably be expected to fulfill this required role. Several studies identified several soil degradation processes due to agricultural development as being major threats to the environment and to sustainable agriculture and hence to food security. The most disturbing aspect was not only the extent of soil degradation that exists in the country, but also the inability to identify and apply effective responses. Fortunately, Morocco has great agricultural potential and agricultural development should continue with strong relief to farmers affected by land degradation. Moroccan agriculture is characterized by the co- existence of both modern agriculture, and the traditional version. Both types of agriculture are under degradative processes due to mis-use of tillage implements, mis-management of crop residues and inappropriate links between grain and livestock productions. One of the early proponents of the concept of No-Tillage goes back to Edwards Faulkner in 1943 in the USA and since then the system continues to dissipate in all five continents, reaching around 100 millions hectares. No-tillage cropping systems are multi- functional within landscapes and economies. They not only produce food and other goods for farm families and markets, but also contribute to a range of valued public goods, such as clean water, wildlife, carbon sequestration in soils, flood protection, groundwater recharge, and landscape amenity value. From the research conducted over the last three decades in the semiarid regions of Morocco, the vast majority of beneficial tillage effects are very transient. Conversely, the harmful effects of conventional tillage systems are long-lasting, if not permanent. Technological change in agriculture is a necessary condition for achieving sustained increases in food production. The present book aims at evaluating the potential of no-tillage practices in the management of soils in semi-arid areas of Morocco. Hence, the present work is intended to describe major achievements in no-tillage research conducted in semiarid Morocco and to present important ways to implement these achievements within the Moroccan rural society. A free economy and trade environment, should normally favor the most efficient utilization of agro-ecosystem’s resources. In other words, No-tillage systems are found and recognized to revert several degradation processes and enhance productivity of most cropping systems. These systems have revolutionized cropping worldwide and in semiarid Morocco localities, resulting in reduced soil erosion, greater soil water conservation, improved soil quality, environment protection and stable and higher crop yields. The straw over the soil decreases soil water evaporation, while each tillage operation increases it and hence the No-till crops are less vulnerable to drought. No-tillage systems, associated with appropriate crop rotations, are important drought management and mitigation strategies for dryland agriculture. Changes in crop production practices due to shifting to no-tillage systems and retention of crop residue at or near the surface produce progressive qualitative and quantitative variations in soil organic matter. These changes resulted in physical and chemical differentiation, mainly at the seed zone. These effects benefited both farmers and society in terms of higher yields, returns and efficiencies. Under no-tillage systems, benefits from improved agriculture’s environmental performance must be added to remunerations of reducing costs of production, increasing production and improving well-being of farmers. Ecologically integrated weed and pest management is required for best yielding and stable productivity under no-tillage systems. In fact, the transitional period from conventional to no-tillage systems required a prudent control of weed and disease infestation. It is found from on-going research that there is a tendency to weed speciation and disease/insect infestation under no-tillage systems, if not appropriately managed. From fragmentary available research on erosion and sedimentation processes, it was validated the worldwide recognition of positive impacts of no-tillage residue covers on runoff and sediment yield control and prevention. Even though, many agronomic and environmental benefits accrue from no-tillage and increasing crop diversity; lack of incentives from the government and social factors often encourage the continued use of intensive tillage and specialized crop production. Hence, it is convenient to ascribe the slow adoption of no-tillage systems in Morocco to a lack of knowledge available to most researchers, developers and their advisers. This book will partially fulfill this information gap. There is a need for the results of such research to be disseminated quickly to national and local government, the general public and - above all - the farming community. No-tillage cropping systems will developed and continue to change in response to economic and social pressures while concern for the state of wildlife and the quality of soil and water has led to further pressures on the way that crops are farmed. There should be an ongoing debate about the future of both no-tillage and conventional farming – not only in Morocco but also in North Africa and global dryland context.
Full-text available
Agriculture in West Asia and North Africa (WANA) is losing momentum. Serious problems of land degradation, desertification, declining soil quality, reduced soil fertility and low agricultural production levels may be irreversible if appropriate measures are not taken soon. Past research in agriculture focused on testing cropping systems under conventional soil management which may no longer be relevant to the WANA region. Most of WANA’s soils need skilled management practices such as no-tillage and stubble retention to ensure sustainable agricultural production. This chapter reviews research on no-till (NT) and conservation agriculture (CA) and their application in rainfed regions of WANA. In WANA countries where water scarcity is becoming endemic, NT could rehabilitate productivity of soils and farmers’ returns, although it can result in lower yields where weeds are not controlled. Institutions need to disseminate the principles and practices of no-till in order to improve productivity and profitability and benefit both the environment and society.
Full-text available
In this study, we assessed the effect of conventional tillage (CT), reduced (RT) and no tillage (NT) practices on the soil CO2 flux of a Mediterranean Vertisol in semi-arid Morocco. The measurements focused on the short term (0 to 96 h) soil CO2 fluxes measured directly after tillage during the fall and spring period. Soil temperature, moisture and soil strength were measured congruently to study their effect on the soil CO2 flux magnitude. Immediately after fall tillage, the CT showed the highest CO2 flux (4.9 g m-2 h-1); RT exhibited an intermediate value (2.1 g m-2 h-1) whereas the lowest flux (0.7 g m-2 h-1) was reported under NT. After spring tillage, similar but smaller impacts of the tillage practices on soil CO2 flux were reported with fluxes ranging from 1.8 g CO2 m-2 h-1 (CT) to less than 0.1 g CO2 m-2 h-1 (NT). Soil strength was significantly correlated with soil CO2 emission; whereas surface soil temperature and moisture were low correlated to the soil CO2 flux. The intensity of rainfall events before fall and spring tillage practices could explain the seasonal CO2 flux trends. The findings promote conservation tillage and more specifically no tillage practices to reduce CO2 losses within these Mediterranean agroecosystems.
Many studies have shown that zero tillage (ZT) in combination with a surface crop residue layer – two components of conservation agriculture (CA) practice – can improve the agronomic water balance by increasing the amount of water that is readily plant available. However, no account has yet been published in which this effect had been fully quantified under rainfed semiarid Mediterranean conditions. To tackle the issue, in the 2009/2010 cropping season we studied the soil water dynamics of wheat grown after barley in northern Syria under two contrasting tillage regimes (zero tillage vs. conventional tillage, CT), two levels of surface residue retention (partial and full) and early and late planting. For a comprehensive quantification of the water balance, we applied the crop-soil simulation model CropSyst for the season under study and for the period 1980–2010 (30 years). Results showed that planting date had a notable impact on crop performance and yield (30-year average, early: 2.68 Mg/ha; late: 2.30 Mg/ha). Simulations indicated that planting wheat immediately after the first sufficient rainfall in autumn bears little risk of crop failure due to early season droughts, and more should be done to encourage farmers to do so. ZT and residue management changed yields only very little, even though in 25 out of 30 years, ZT yields were higher than CT yields. About 55% of the seasonal precipitation (∼150 mm) was lost by unproductive soil evaporation, whereas ZT and residue retention had only a minor mitigating impact; too little to be clearly distinguishable by field observations. A potential obstacle for meticulous simulation of CA with CropSyst is the model's inability to simulating the dynamic nature of tillage, i.e. its decreasing impact over time, and the beneficial effect of ZT and residue retention on soil water infiltration. However we argue that such impact may be limited on soils with self-mulching characteristics that are common in the region of this study.
The objective of this article is to review: (a) the principles that underpin conservation agriculture (CA) ecologically and operationally; (b) the potential benefits that can be harnessed through CA systems in the dry Mediterranean climate; (c) current status of adoption and spread of CA in the dry Mediterranean climate countries; and (d) opportunities for CA in the Central and West Asia and North Africa (CWANA) region. CA, comprising minimum mechanical soil disturbance and no-tillage seeding, organic mulch cover, and crop diversification is now practised on some 125 million ha, corresponding to about 9% of the global arable cropped land. The area under CA is spread across all continents and many agro-ecologies, including the dry Mediterranean climate. Empirical and scientific evidence is presented to show that significant productivity, economic, social and environmental benefits exist that can be harnessed through the adoption of CA in the dry Mediterranean climates, including those in the CWANA region. The benefits include: higher productivity and income; climate change adaptation and reduced vulnerability to the erratic rainfall distribution; and reduced greenhouse gas emissions. CA is now spread across several Mediterranean climate countries outside the Mediterranean basin particularly in South America, South Africa and Australia. In the CWANA region, CA is perceived to be a powerful tool of sustainable land management but it has not yet taken off in a serious manner except in Kazakhstan. Research on CA in the CWANA region has shown that there are opportunities for CA adoption in rainfed and irrigated farming systems involving arable and perennial crops as well as livestock.
Conservation agriculture in North Africa. Pages 293-310 in Conservation Agriculture: Global Prospects and Challenges CABI
  • H Boulal
  • M Mourid
  • H Ketata
  • A Nefzaoui
Boulal, H., M. El Mourid, H. Ketata and A. Nefzaoui. 2014. Conservation agriculture in North Africa. Pages 293-310 in Conservation Agriculture: Global Prospects and Challenges (R.A. Jat, K.L. Sahrawat and A.H. Kassam, ed.). CABI, Wallingford, UK.
Critical steps to no-till adoption. Pages 479-495. In: No-till farming systems
  • R T Derpsch
  • M Goddard
  • Y Zoebisch
  • W Gan
  • A Ellis
  • S Watson
  • Sombatpanit
Derpsch, R. 2008. Critical steps to no-till adoption. Pages 479-495. In: No-till farming systems, T. Goddard, M. Zoebisch, Y. Gan, W. Ellis, A. Watson, and S. Sombatpanit (ed.), Bangkok:World Association of Soil and Water Conservation (WASWC), p 479-495.
CA Adoption Worldwide. FAO-CA website available online at: (http
  • R Derpsch
  • T Friedrich
Derpsch R. and T. Friedrich. 2011. CA Adoption Worldwide. FAO-CA website available online at: (