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Cover Crops

Value Chain
Annual Average Rainfall
Climatic Zone
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Cover Crops are incorporated into farming systems and planted in between growing seasons with the primary purpose of preventing soil erosion and improving nutrient content, and promoting soil quality in general, rather than being planted as a regular food or cash crop. Cover crops can also be utilised for food stuff, fodder or cash crops; but these outcomes are usually secondary to the main aim of improving/retaining soil quality. An additional benefit from growing cover crops is reduction in weed growth, and pests and diseases; increases in water availability in the soil; and increased soil biodiversity. Additional benefits are recognised from cover crops in areas with steep slopes, as the retained plant cover contributes to reducing erosion. Cover crops can be combined with other practices including intercropping practices and erosion control measures to further enhance soil quality and structure. Incorporating cover crops into farming systems increases farmers resilience to climate impacts through improving soils, reducing fossil fuel consumption, and increasing soil carbon sequestering. Extension guidance can be beneficial when selecting relevant cover crops to achieve the above outcomes.

Technical Application

To effectively implement cover crops:

  • Step 1:  Research whether locally available crops (especially legumes) provide potential options for cover crops.
  • Step 2: Establish a demonstration plot could provide farmers with an example of how cover crops function.
  • Step 3: Plant cover crops between primary crop growing systems to improve soil fertility, quality and nutrients.
  • Step 4: Monitor soil structure, nutrient levels, and field integrity to ensure efficacy.
  • Step 5: Incorporate cover crops with other climate smart practices enhance soil, including: Intercropping (Technical Brief 07), Crop Rotations (Technical Brief 09) Reduced/No-tillage Options (Technical Brief 12) etc
Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Cover crops improve soil conditions, providing an enabling environment for agricultural productivity.
Increase Resilience
In changing climates, cover crops can contribute to adaptation strategies, improving soil health.
Mitigate Greenhouse Gas Emissions
Retains and improves soil quality, including carbon sequestration.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_15_CoverCrops_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Cover crops protect soils from erosion and prevent soil nutrient loss.
  • Preventing weed growth, control pests and disease, increase water availability in the soil and increase soil biodiversity.
  • Cover crops may be non-traditional food crops, fodder and/or cash crops.
  • Low cost option for protecting soils and improving soil fertility.

Drawbacks

  • May take time to determine suitable to improve soils.
  • May increase labour demands as new or unfamiliar crops are incorporated into farming systems.

Trash Lines

Value Chain
Annual Average Rainfall
Climatic Zone
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Trash lines are the incorporation of lines of organic materials spread across contours of hilly agricultural fields - strips of heaped straw or weed materials that have been collected during primary cultivation of the land. Trash lines have been found to direct runoff in field and act as an erosion control method. Through decomposition, the trash line material acts as a type of compost adding nutrients to the soil, adding more organic material year on year, should the farmer continue to build this line. This is a climate smart approach as it contributes to soil health, capturing more nutrients and carbon in the soil, and in turn promoting sustainable agricultural productivity. In changing climates, implementation of this practice can contribute to adaptation strategies.

Technical Application

To effectively undertake trash lines:

  • Step 1: Collect straw, stalks, picked weed or other organic materials from field or surrounding area.
  • Step 2: Establish contour lines using method identified in contour planting (Technical Brief 16).
  • Step 3: Contour lines for trash lines should be spaced between 5 to 10 m apart.
  • Step 4: Heap straw along contour lines on hilly or sloped fields to be approximately 0.5 m wide and up to 0.3 m in height.
  • Step 5: Trash should be piled on annually or as the field is prepared. Lines can be maintained for a few years and then decomposed materials can be mixed into the soil.
Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Contribute to soil health and therefore agricultural productivity.
Increase Resilience
In changing climates, strategies such as this can contribute to retain and improving soil health.
Mitigate Greenhouse Gas Emissions
Helps retain carbon in soil.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_14_Trashlines_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Low cost option for soil and water conservation on sloped fields.
  • Increase of organic materials in fields.
  • Green manure (Technical Brief 02) production in the field.

Drawbacks

  • Increased workload to implement trash lines but low effort to maintain.

Mulching

Value Chain
Annual Average Rainfall
Climatic Zone
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Mulching is the process of introducing vegetative material to the surface of soil in fields to provide soil cover, reduce evaporation, maintaining an even soil temperature and ultimately improve organic content in soil. These materials can include grasses, crop residues, tree bark and other plant materials, even including seaweed if it is available. These materials should be well decomposed, and mixed well into the top soil when the growing season is over. Mulching improves soil fertility by creating a positive soil environment favouring microbial activity and other promoting beneficial organisms such as earthworms, increases moisture retention, stabilises soil temperatures (protecting soils from both heat and cold), reduces soil erosion and restricts weeds. The temperature control keeps roots and plant bulbs cool in the summer and warm in the winter. It can be utilised on all scales of farm, depending upon the availability of input mulch materials. It is considered a climate smart approach as it sequesters carbon in the soil and promotes soil health which in turn maintains agricultural productivity and the ability of a farmer to adapt to climate changes. In some cases, shredded plastic is sometimes used as a synthetic soil cover, but this is not considered climate smart, as it does not integrate organic matter to the soil, instead introducing plastics.

Technical Application

To effectively undertake mulching the following should be carried out. Tools required: shovel, scissors or shears.

  • Step 1: Gather organic materials from the farm and other external sources if possible. grasses, crop residues, wood chips, tree backs and other plant materials.
  • Step 2: Prepare a location to stock-pile mulch material. A large farm will need a substantial area or pit to achieve this. For smaller operations, mulch can be stored in open-topped barrels and bags punctured for air holes. Storage must allow moisture to contribute to the decomposition process, but no become waterlogged.
  • Step 3: Chop/shred organic material and add to the stock-pile. With larger amounts of material, a motorised, or pedal driven chopper/shredder is useful.
  • Step 4: Allow materials to decompose, but do not leave for extended periods as nutrients and minerals will be lost.
  • Step 5: At the end of the growing season, remove any remaining weeds from the soil surface.
  • Step 6: Spread mulch material over the surface approximately two centimetres deep.
  • Step 7: In firmer or more compacted top soils, lightly work the mulch into the upper soil.
  • Step 8: Lightly water area where mulch has been applied.

Mulch should be applied annually as mulching materials will decompose.

Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Improving soil health through practices such as mulching promotes productivity.
Increase Resilience
In changing climates, with shifting rain patterns, and increasing temperatures, practices such as mulching help retain soil health.
Mitigate Greenhouse Gas Emissions
Mulching provides soil cover, promoting retention of carbon in the soil, and also introducing organic content to the soil itself.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_13_Mulching_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Mulching improves soil structure, fertility and quality, stabilising soil temperature and retaining moisture.
  • Mulching can increase nutrient content in the soil.
  • Mulch can contribute to reducing soil erosion.
  • Mulching contributes to preventing weeds from growing.
  • If not used, mulch can be sold to other farmers.

Drawbacks

  • Despite positive benefits, requires substantial labour inputs, hence the need for on-farm labour resources, or the ability to hire.
  • Mulch can spoil if not managed correctly.
  • Considerable quantities of mulch are needed to cover fields.
  • Again, if not managed correctly, can harbour pests, diseases and weeds (seeds).
  • If over-applied, can result in a toxic environment.

No Tillage

Value Chain
Annual Average Rainfall
Soils
Climatic Zone
Water Source
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

No-tillage or reduced-tillage farming involves growing crops without ploughing or reducing the use of machinery in preparing fields for planting. Excessive tillage can have major impacts on soils and the environment including loss of organic matter and soil organisms, increased soil erosion and pesticide runoff, reduced soil fertility, loss of soil structure, etc. Thus, implementing no- or reduced-tillage can help farmers in conserving soil quality and in many cases, increase crop production.

In implementing no-tillage processes, land is not or is minimally disturbed and crop residues are normally left on the soil surface with minimal use of implements. Reduced tillage practices include technological changes such as using more efficient ploughing tools and/or implementing strip-till, zone-till or ridge-till processes. Most reduced tillage systems are implemented in conjunction with cover crops and mulches to protect soil structure.  Tilling by hand or animal means are considered reduced tillage methods.

The adoption of no or reduced tillage practices reduces the amount of fossil fuels consumed by farmers and increases carbon sequestration as soil carbon is not exposed or released in the atmosphere and is thus a climate smart practice.

Technical Application

Switching to no-till or reduced tillage should be planned at least a year in advance so preparations can be made necessary implements can be obtained. Implements should match farm labour availability. You will also need to decide if no till or reduced tillage methods are appropriate based on farm area and desired crops, and start with a small area to determine feasibility. Cereal and legume crops are suitable for no tillage while vegetables and other crops often require some tillage – i.e. reduced tillage.

There are two forms of no-tillage, conventional and organic. Conventional no-tillage includes the application of herbicides to manage weeds, prior to and after planting. Organic no-tillage does not incorporate the use of herbicides, but includes other methods for controlling weeds, including cover crops, crop rotation and free-range livestock. Organic no-tillage is more suitable as it assists mitigate any climate change impacts on the farm.

No till

  • Step 1: Prepare fields using conventional (herbicide application) or organic processes include cover crop (Technical Brief 15) and crop rotation (Technical Brief 09).
  • Step 2: Test soils – aiming to balance nutrient and pH levels. In the case of acidic soils, add small amounts of lime each year.
  • Step 3: Avoid soils with bad drainage, as they become water-logged.
  • Step 4: Level the soil surface, removing uneven areas to assist even seed planting.
  • Step 5: Eliminate soil compaction.

Reduced Till

  • Step 1: This approach is similar to regular tillage, but with significantly less disturbance of the soil. Tilling is only done where needed, and the rest of the soil is undisturbed.
  • Step 2: Strip-tillage or zone-tillage involves tilling and seeding in 15 cm strips leaving areas in-between undisturbed.
  • Step 3: Ridge-tillage involves preparing ridges post-harvest and letting them settle over time to be planted the next seeding period; with ridges not more than 60 cm apart.

More information of each of these specific practices should be sought prior to implementation.

Crop rotation is a complimentary farming method when practicing no-tillage, as it promotes maximum biomass levels for permanent mulch cover, while controlling weeds (with pre- and post-emergent herbicides), pests, and diseases, as well as improving soil nutrition and fertility.

Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Improved soil structure and increased microbial and invertebrate activity in the soil makes nutrients more available to plants.
Increase Resilience
Increased water infiltration and soil biodiversity mitigates the effects of short-term dry spells.
Mitigate Greenhouse Gas Emissions
Locks more carbon in the soil. Reduced ‘passes’ in mechanised systems reduces fuel inputs required.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_12_No%20Tillage_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Increased soil fertility, organic matter and soil structure, and beneficial organisms (earthworms, etc).
  • Reduced compaction of soils.
  • Prevention of soil erosion.
  • Reduction in fossil fuel consumption.
  • Increased soil carbon sequestration.

Drawbacks

  • A positive response can be delayed for up to three years.
  • Effective weed management may require the application of herbicides.
  • Possible decreases in crop productivity if not carried out effectively.

Crop Diversification

Value Chain
Climatic Zone
Water Source
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Many farmers grow one crop repeatedly on the same field over-and-over again. Crop diversification is the cultivation of several crops of a different species or variety (of one crop) in one plot at any given point in time. The main advantage of implementing crop diversification is that it enhances household climate resilience through reducing risk of monocrop failure due to pests, disease, low rainfall and other climate risks.

Employing crop diversification may also provide opportunity of more diversified income sources and dietary diversity. Farmers can simultaneously grow both food crops, fodder and cash crops in an attempt to increase household food security and improve household incomes. There are also indications that crop diversification can increase crop productivity, which for poorer households can have significant positive impacts. For better capitalised farms, return on specialisation may be higher, and will likely not realise the desired returns.

Technical Application

To effectively undertake crop diversification:

  • Step 1: Identify potential market opportunities for alternative crops in local/sub-national/national area.
  • Step 2: Determine crops that farmer wishes to plant and the purpose whether it be household food stuff, cash crop or fodder crop.
  • Step 3:  Establish local demonstration plots at the local level growing non-traditional crops that have market demand and can be incorporated into local farming systems.
  • Step 4: Prepare smaller plot through clearing and weeding. CCARDESA recommends a no tillage approach (Technical Brief 12).
  • Step 5:  Secure seeds of desired crops and follow planting guidance if the crop has not been previously grown. Sow seeds on small plot.
  • Step 6: Track progress of crop and harvest and process as required.
  • Step 7: Discuss cost benefit of growing diversified crops with farmers.
  • Step 8: Farmers should gradually integrate a new crop(s) into their farming system to ensure that they are comfortable with diversifying at a greater scale.
Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Increased yields of rotated crops due to lower incidence of pests/ diseases.
Increase Resilience
Help reduce exposure to pests/diseases and drought/heat stresses and market fluctuations by having greater diversity.
Mitigate Greenhouse Gas Emissions
Potential to lock more carbon in the soil, especially if fallows or cover crops are incorporated.
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_10_Diversification_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Diversification provides opportunity to increase farmer resilience.
  • Substantial opportunity for increased crop productivity
  • Food security, farm income, household nutrient improvements.
  • Scaled up as farmers gain confidence.

Drawbacks

  • Farmer hesitation.
  • Require enough space to introduce additional crop.
  • Failure in diversified variety/species may dissuade farmers in the future.
  • Not encouraged for better capitalised farms, as returns to specialisation can be higher.

Crop Rotation

Value Chain
Climatic Zone
Water Source
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Monocropping in one field for many subsequent years will cause nutrient depletion in that field and lead to less productive returns. Crop Rotation is the process of planning the planting and harvesting of different crops planted on the same field over subsequent growing seasons, allowing less nutrient depletion and if applied effectively, increasing soil nutrients through nitrogen fixing etc. This farming practice also assists with weed control, prevents soil erosion, and is the most efficient and economical way to break the biological cycles of plant pests and diseases, mitigating the effects of pests/disease as they become more prevalent due to climate change and helping farmer diversify crop production.  Research has shown that rotation between nitrogen consuming crops such as maize and nitrogen depositing plants such as soybeans can provide a healthy balance of nutrients. This farming practice is advantageous for smallholder farmers who are less able to leave fields fallow for extended periods of time, as well as for commercial farmers wanting to reduce pesticide use. It is seen as climate smart as it breaks pest and disease cycles, returning nutrients to the soil, thereby supporting more predictable yields in times of climate pressure, and locking more carbon in the soil.

Technical Application

An example of crop rotation is maize, followed by a legume. Grain SA has reported a 12 % increase in maize production following rotation with legumes such as cowpea. Furthermore, the legume yields often increase following rotation with the grain crop, and sometimes responding differently to the crop type. For example, soybean yield has been measured at 20 % higher following sorghum than maize. To effectively undertake crop rotation:

  • Step 1: Determine which cereal crops and legumes are available in the area of interest.
  • Step 2: Prepare land through clearing, weeding. No-tillage approaches are preferable (Technical Brief 12).
  • Step 3: Plant a leafy cereal crop (maize or sorghum) and let the crop mature and harvest once ready. Once harvested, bend stalks over to increase biomass.
  • Step 4: If possible, allow field to fallow for a short period. If this is not possible, practice cover cropping (Technical Brief 15).
  • Step 5: Prepare land again, and sow second crop, usually a legume to improve soil structure and fertility. Harvest crop once ready.
  • Step 6: Repeat process. It is possible to include more than two crops into crop rotation if desired.

It is advisable to carefully monitor yield for demonstration purposes, run test plots if necessary.

Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Breaks pest and disease cycles. Returns nutrients to soil.
Increase Resilience
More predictable yields from each crop and a reduced risk of crop loss.
Mitigate Greenhouse Gas Emissions
Helps to lock more carbon into the soil if fallow/cover crops/green manure is included. Can reduce fertiliser requirements.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_09_CropRotation_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Improved soil fertility and protect soil.
  • Effect and cost-effective way to break pest/disease cycle.Food security/farm income increase.
  • Food security/farm income increase.
  • Nutrient fixing.

Drawbacks

  • Time should be allowed between harvest and planting of different crops.
  • Cultural shift away from traditional crops.
  • Limited market opportunities for non-traditional crops.

Relay Cropping

Value Chain
Climatic Zone
Water Source
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Relay cropping is a form of intercropping where two or more crops are grown simultaneously during part of their life cycles. Intercropping often involves maize and legumes, which increases nitrogen fixing in soils and increased biomass production. The second (or succeeding) crop is planted after the reproductive stage (flowering) of the existing crop but before harvesting. Some of the advantages of relay cropping include better erosion control due to crop cover, reduced spreading of pests and diseases, and crop diversification, plus general soil health. As an added benefit, it mitigates the emission of greenhouse gases through reducing nitrate leaching and increasing carbon sequestration. There is also potential socio-economic benefits for farmers as in many cases relay cropping increases crop productivity.

However, this form of intercropping is not easily implemented in large-scale agricultural systems due to complications in weed control and challenges associated with operating mechanised equipment on fields with relay cropping.

Technical Application

To effectively implement relay cropping, the following steps should be carried out:

  • Step 1: Test/experiment with locally available crops to determine if they are complementary and can grow concurrently - cereal crops and legumes are complementary and can generally grow concurrently.
  • Step 2: Prepare land through clearing, weeding and a no-tillage approach (Technical Brief 12).
  • Step 3: Plant cereal crop first according to normal planting season schedule –during rainy season. Space this cereal crop 70 cm by 50 cm apart.
  • Step 4: Prior to cereal harvest, plant the legume crop between cereal crop rows with spacing based on legume planting efficiencies (researched prior to planting for optimum growth).
  • Step 5: After cereal has been harvested, bend the dried stalks down to provide more ground cover.
  • Step 6: When legumes are ready for harvest, collect the productive pod/seed/bean/nut and leave the stalk uprooted in the field to maximise ground cover.
Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
More efficient use of available resources. Increased yield from the same field.
Increase Resilience
If legume – maize/sorghum relays are employed the risk of crop loss is reduces and dietary diversity is enhanced.
Mitigate Greenhouse Gas Emissions
Helps lock more carbon in the soil.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_08_RelayCropping_2019-10-17_0_0.pdf
Benefits and Drawbacks

Benefits

  • Increased and diversified crop yield.
  • Improved soil quality preventing leaching, and introducing nutrients.
  • Increased land cover reducing erosion and improving carbon capturing.
  • Food security/farm income increase.

Drawbacks

  • Weeding makes this approach labour intensive, and planting and harvesting can become less efficient. This requires consideration, especially if women’s workload increases as a result.
  • Carried out precisely to ensure crops are compatible, planting is undertaken at correct times and harvesting is low impact to avoid crop damage.
  • Possible competition between plants for nutrients, water, space, etc.

Intercropping

Value Chain
Climatic Zone
Water Source
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Intercropping is a process of growing multiple crops either together or in proximity to each other on one piece of land, thereby improving crop production, reducing and preventing land degradation and increasing crop output.

There are different methods of intercropping:

  • Mixed intercropping – two or more crops are seeded together and harvested together.
  • Row/strip intercropping – two or more crops planted on the same field but planted in alternate rows.

Crops selected for intercropping should not have similar properties or compete but should be selected to complement one another and be mutually beneficial. For example, deep rooted crops can be intercropped with shallow rooted crops, so as to not compete for water or nutrients. Intercropping helps achieve ecological benefits not possible with monocropping systems. Intercropping is commonly practiced for maize-legume systems, where legumes introduce nitrogen into the soil benefiting maize production and improving soil fertility during crop growth. Furthermore, the legume crops can be utilised for fodder for livestock. This practice is particularly beneficial for smallholder farmers, who can grow multiple crops on small plots to receive multiple benefits including improving production/yields, and increasing household food security. Intercropping is also a climate-smart practice as it mitigates farmer risk to climate variations, through diversifying and increasing crop production, reduces threats of pests and disease, and increases carbon sequestration in soils and biomass production.

Technical Application

To implement intercropping practices:

  • Step 1: Consider soil properties - has the soil been mono-cropped and/or is it leached?
  • Step 2: Consider crop characteristics – will crops be competing for nutrients, water space, sunlight or will they be mutually beneficial adding nutrients
  • Step 3: Prepare land through clearing and weeding. A no-tillage approach is recommended – see Technical Brief 12.
  • Step 4: Select whether the farmer should undertake Mixed Intercropping (Good for smaller plots however plants compete) or Row/Strip Intercropping (crops less likely to compete). See also KP07 – Climate Smart Planting Options for Maize and Sorghum.
  • Step 5: If mixed intercropping is selected, sow two crops simultaneously mixing seeds to together while planting. Harvesting may not be a simultaneous process as different crops have different growth rates and seasons.
  • Step 6: If row/strip intercropping plant two or more crops in the same field but in separate rows patterns. Rows should be spaced 50 cm apart and can have a row of 1:1 or 2:1 ratio of cereal crop to legume.
  • Step 7: Harvest as individual crops require, be careful not to disrupt other crops that have not yet matured.
Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Higher levels of production from the same area of land, due to healthier soils.
Increase Resilience
Reduces losses due to pests and diseases and can mitigate losses due to drought as they increase organic matter, with increased water holding capacity and stimulated bacterial growth.
Mitigate Greenhouse Gas Emissions
Helps lock more carbon in the soil and plants.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_07_Intercropping_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Increased and diversified crop yield.
  • Food security/farm income increase.
  • Nutrient fixing.
  • Food security/farm income increase.

Drawbacks

  • Competition between plants for nutrients, water, space, etc.
  • Increase farmer workload as weeding, planting and harvesting are less efficient. Requires consideration especially if women’s workload increases as a result.

Biochar

Value Chain
Annual Average Rainfall
Climatic Zone
Water Source
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Biochar refers to a fine-grained charcoal, rich in organic carbon compounds, used to improve soil quality through enhanced nutrient and water holding capacity of soil, reducing total fertiliser needs. Biochar is a stable solid produced from the controlled burning of plant and waste feedstock, including wood chips and pellets, tree bark, crop residues (straw, maize stovers, nut shells and rice hulls), grain, sugarcane bagasse, chicken litter, diary manure, sewage and paper sludge. Biochar is used as a soil conditioner as part of soil amendment strategies, improving the workability of soil, particularly those with heavy clay components.. The application of biochar to soil is a strategy to minimise the climate and environmental impact of cropland systems, such as the application of synthetic fertilisers, and improve soil quality through enhancing its physical-chemical characteristics. This agricultural practice improves soil structure, nutrient cycling and water retention, and the high stability of biochar carbon compounds contributes to the reduction of green-house gas emissions by increasing carbon sequestering in soils. Biochar is shown to be effective in improving soil conditions in acidic, sandy and clay-rich soils, improving the physical characteristics, and is classified by the FAO classifies as an adaptation strategy and contributes to mitigation of climate change as the processes captures and stores carbon in soils create other secondary socio-economic benefits, through additional fuel sources, and economic opportunities for production. Biochar can either be purchased or produced on-farm on a small or large scale. Collective action may benefit communities, so discussion with neighbours and community leadership may be necessary, especially if a biochar.

Technical Application

To effectively implement biochar the following should be carried out. Tools required – shovel and a metal sieve.

  • Step 1: Acquire charcoal from local vendor, and sieve or grate the charcoal into fine material in a pile. Biochar should not be applied to soil directly after production. It should be allowed to ‘rest’ for one to two months.
  • Step 2: Rotate the pile every 2-days for a period of up to 10-days (total).
  • Step 3: Prior to application, aim to wet (but not waterlog) biochar stock with water or preferably urine. If done when still warm, it will fracture the charcoal, increasing surface area for absorption.
  • Step 4: Spread the biochar evenly across soil prior to planting and let it settle or mix with the top layer of soil. One to three kg/m2 is recommended, depending on the degree of soil required.
  • Step 5: Regularly monitor soil pH, water retention and soil texture, keeping records if relevant to ensure that improvements are realised, and negative impacts do not arise.

Biochar can be produced on-farm, but will require collection of plant and waste feedstock (see above). Biochar can be produced on-farm using a trench. A biochar trench is a dug recess where crop residues are burned to create charcoal. Tools required are a shovel and one or more roofing sheets (one-metre long).

  • Step 1: Dig trench 50 to 70 cm deep, and one to two metres long, ensuring that roofing sheets fully cover the trench void.
  • Step 2: Start a fire in one end of the trench, throwing in loose crop residue or other organic waste, keeping the fire under control (not creating large flames and smoke).
  • Step 3: Keep fire burning until trench is full of char.
  • Step 4: When the trench is full, and flames have burned-out, cover the trench with the roofing sheet, sealing edges with loose soil, trampling it down to ensure closure.
  • Step 5: Leave the covered trench for five to six hours to extinguish.
Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Makes nutrients more available to plants and increases water retention. Can increase pH.
Increase Resilience
Improves water retention. Remains in the soil for a long time.
Mitigate Greenhouse Gas Emissions
Capturing carbon in soils thereby reducing emissions.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_03_Biochar_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • The production and application of biochar reduces GHG emissions of cropland systems due to the properties of the biochar itself, and reduction in the application of synthetic fertiliser.
  • Can improve physical and chemical composition of soil, especially in acidic, sandy and clay-rich soils; soil nutrient cycling and water retention.
  • Can reduce fertiliser and irrigation requirements.
  • Potential socio-economic opportunities for biochar producers, if not produced on-farm.
  • Improved food security from production of secondary fuel source.
  • Provides an appropriate and sustainable mechanism for dealing with crop residues and biomass.
  • Can be mixed with compost during application to increase performance of soil amendments.

Drawbacks

  • Requires sustainable non-wood supply of organic matter for production so as not to increase deforestation.
  • Long-term impacts not fully understood.

Green Manure

Value Chain
Climatic Zone
Water Source
Decision Making
Farming Characteristics
Mechanisation
Labour Intensity
Initial Investment
Maintenance Costs
Access to Finance/Credit
Extension Support Required
Access to Inputs
Access to Markets
Gender/Youth Smart
Description

Green manure (otherwise known as cover crops), is a climate smart fertiliser process that involves growing plants (mainly legumes) and distributing uprooted or sown crop-parts to wither and cover soil. It provides soil coverage to enhance biological, physical and chemical properties of soil while mitigating soil erosion, supressing weed growth, adding biomass to soils, improving soil structures, promoting biological soil preparation, and reducing pests, diseases and weed growth. These functions can increase economic return, reduce the need for herbicides and pesticides, while increasing productivity and potentially the quality of crops. It can also increase soil nitrogen, improve soil fertility, conserve soil humidity and reduce fertiliser costs. Green manure also has low management costs, presents good conservation characteristics, and improves biodiversity. Green manure is a feasible and sustainable option for farmers to improve soil quality and productivity, depending on local context and availability of different leguminous plants that best fit for farmers’ cropping systems. Examples of leguminous plants that can be used in southern Africa include: Mucuna (Mucuna pruriens); Sunhemp (Crotalaria juncea), Lab-lab (Lablab purpureus); Pigeon pea (Cajanus cajan); Cowpea (Vigna unguiculata) and Butterfly pea (Clitoria ternatea). Green manure has climate smart benefits as contributes to sustainable maintenance of agricultural production without the use of chemical fertilisers and depending upon the cover crop can contribute to adaptation of agricultural practices to climate change. Furthermore, coverage of soil with additional plant material can assist with carbon sequestration in soil. Not only does growing a secondary green manure crop provide a soil amendment benefit, but the crop can also be used as fodder for livestock. As the most common green manure plants are legumes, the pods and seeds can be fed to livestock while leaving the crop residue to perform the cover crop function in in the fields.

Technical Application

To effectively apply a green manure approach, the following should be considered:

  • Step 1: Select legumes that grow well under local conditions and in local soils. Green manure crops should be resilient and require few crop management practices. A thorough investigation should be made to ensure that green manure crops are appropriate for the local conditions in terms of rainfall, climate, soil pH and texture, and salt tolerance.
  • Step 2: Identify the appropriate time for planting the green manure crop to ensure growth, but not impacting the primary crop. Especially if the secondary crop is a climber/creeper. Main crop may need to be mature before planting the manure crop, as if a creeper, it may outcompete or constraint growth of maize or sorghum plants.
  • Step 3: If seeking to enrich soil properties, the farmer must allow crop residue to remain in the soil longer. This is particularly relevant with multiple uses – e.g. soil amendments and livestock fodder. In these cases, pods can be harvested for fodder, and the remaining plant residue left in the field to cover the soil.
  • Step 4: Crop planting should be alley cropped between the primary crop rows, allowing management of the primary and secondary crops, also reducing the competition between the primary and the secondary crop. If the secondary crop also has pest management properties, it may be beneficial to consider boundary planting.
  • Step 5: When harvesting the secondary crop, the farmer should consider leaving the residue in the ground. If it is uprooted, it should left on the soil surface. A common mistake is to remove it from the field and accumulate it in one location, missing the benefits of cover-crops, and exposing the residue to decay.

Unless local examples are available, small test plots should be used to test different cover crops to determine which is the most appropriate, and if necessary, demonstrate value to farmers and communities. As the secondary (green manure) crop is not a direct cash-crop, you may need to ensure expectations are measured. It may take several years to develop enough green manure crop to contribute to crop production; hence, crop production has to fit around existing cash/subsistence crops. Furthermore, benefits may not be realised within a single planting season., e.g. Nitrogen may only be available in the soil in the subsequent season.

Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Green manure can maintain or increase agricultural productivity through improved soils.
Increase Resilience
Adjustment of practices to include cover crops allows farmers to diversify crop types, and produce their own fertilisers.
Mitigate Greenhouse Gas Emissions
Reduction in carbon released from soil.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_02_GreenManure_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Green Manure is a non-tillage method that promotes soil fertility through enhancement of soil organic content. In doing so, it mitigates erosion, maintains soil humidity, and promotes biological activity.
  • Many green manure plants can be used to feed livestock if there is an excess
  • Green manure cover crops also make organic matter to apply – compost requires work and time to develop, whereas this approach sees it added immediately.
  • Cover crops can reduce weed competition by shading soil.
  • If using legumes, they can thrive in poor quality soils.
  • Cover crops such as Cow pea can also be used for animal and human consumption.

Drawbacks

  • Require access to seedbanks for legumes and other viable cover crops.
  • May require the testing of crops in test plots prior to implementation.
  • If so, community action may be required to test varieties and make decisions.
  • Farmers may require more land to plant the same amount of the main crop, as they need to be intercropped with the cover crop. This can be unattractive to some farmers.
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