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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.

Integrated Soil Fertility Management (ISFM)

Value Chain
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

Integrated Soil Fertility Management (ISFM) refers to a set of agricultural practices that can be applied simultaneously to improve agricultural productivity through increasing soil nutrients and improving crop water use. ISFM includes a broad range of agricultural practices that have all been adapted to local conditions to improve soil nutrients and include the combined application of the following approaches:

  1. Utilisation of organic fertilisers such as green manure, compost and crop residues.
  2. Application of locally available soil amendment methods, such as lime and biochar.
  3. Implementation of techniques like germplasm, agroforestry, crop rotation, intercropping etc.
  4. Limited use of inorganic or mineral fertilisers – seen as the last option in ISFM, when other interventions are not achieving optimal results.

ISFM can be successful for most arable farmers and has been known to double productivity and increase farm-level incomes by 20 to 50 percent if implemented correctly. It focuses on a series of practical approaches to sustainable farm productivity through locally available and affordable options for maintaining soil fertility and productivity, and is seen as a viable approach to reduce over-reliance on inorganic fertiliser. ISFM permits short- and long-term increases in productivity of cash crops and food security, and is considered climate smart as the combined ISFM approach maximises fertiliser uptake and sequestration of carbon in soil, allowing sustainable agricultural intensification driven by improved soil structure and fertility.

Technical Application

In addition to agricultural inputs and the following technical implementation steps, ISFM requires the farmer to consider farm size (land area), and property rights (land tenure) to ensure that investments are efficient and sustainable.

To implement ISFM approaches, the following should be considered:

  • Step 1: Prepare a needs assessment based on understanding of farm challenges – low or declining productivity, soil fertility, low organic content, etc
  • Step 2: Measure fields that require attention to understand volumes of inputs required.
  • Step 3: Develop (or update) an agricultural calendar to use as a platform for discussion between farmer(s) extension officer(s).
  • Step 4: Develop plan and schedule/programme of locally appropriate ISFM interventions between farmer(s) and extension officer(s), obtaining guidance from agricultural suppliers where necessary (lime application, etc). As ISFM is a blended approach, the plan should consider short and medium to long term interventions and outcomes.
  • Step 5: Examine cost implications of the plan, revising where necessary based upon available resources, and if necessary/available apply for credit to fund investments.
  • Step 6: Assess labour requirements within the ISFM plan to ensure that they can be fulfilled, and considerations of gender and youth have been accommodated – women are not expected to do the majority of work, and children are not missing school.
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
Improves soil structure. Increases soil fertility.
Increase Resilience
Aims at sustainable intensification, increasing resilience through more predictable production.
Mitigate Greenhouse Gas Emissions
ISFM has the potential to reduce greenhouse gas emissions owing to greater uptake of Nitrogen-based fertilisers by crops and soil carbon sequestration.
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_06_ISFM_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Applying an ISFM approach can be a sustainable way to improve/rehabilitate soil fertility.
  • ISFM is intended to optimise a combination of CSA strategies to achieve maximum outcomes.
  • The focus should be on leveraging locally available materials and resources to improve productivity.
  • ISFM should be seen as a scalable approach, involving a range of interventions that match available inputs and financial and human resources.

Drawbacks

  • Lack of knowledge of applying the different strategies individually or in combination.
  • Potentially high transaction costs as the process involves multiple interventions.
  • Lack of credit facilities.
  • Availability of labour.

Lime Treatment of Soil

Value Chain
Soils
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

Soil acidification is a widespread problem across southern Africa, often driven by monocropping with cereals and occurring as a result of erosion, compost decomposition and soil leaching. Applying lime to soil is regarded as a key management practice in agriculture to balance pH, enhancing crop productivity, water penetration and absorption of major nutrients by crops. Most crops grow best in soils with a pH between 6.5 and 6.8. Acidity constrains crop growth below pH levels of 5.5. Agricultural lime is limestone mined as a rock that is crushed into various particle sizes ranging from course to fine particles and can be applied in areas where there is high soil-acidity due to high levels of manganese and iron. Lime texture also determines the speed of absorption in the soil; that is, fine-lime reacts more quickly than more granular lime. However, the use of lime must be managed appropriately to avoid losing other nutrients in the soil. This practice is considered climate smart as it assists with adaptation strategies through improvement of soil fertility, whilst improving productivity at modest application rates, noting that annual application is not recommended.

Technical Application

Before applying lime to increase lower soil pH the following should be considered. Equipment required: soil pH testing kit, protective goggles and mask, agricultural lime, shovels/forks/hoes, and disk harrow, drag harrow or hoe if available.

  • Step 1: Use a pH testing strip to determine soil pH levels, making sure to test surface and sub-surface acidity.
  • Step 2: Measure area of land to be treated in order to determine amount of lime for purchase. Application should be calculated as metric tonne per hectare, depending on soil pH and crop. Lime requirements will differ depending on soil type and level of acidity in the soil. Application volumes can be guided by suppliers.
  • Step 3: Purchase lime according to requirements from agricultural supplier. Savings could be realised if purchasing as a group of farmers.
  • Step 4: Apply lime to the soils at least two months prior to planting directly after harvesting to allow the lime to react with the soil, and positively impact the pH.
  • Step 5: Mix lime and soil well in order to reduce soil acidity. This is normally achieved through disk tilling but can be done manually using a drag harrow or hoe. However, this can be an intensive process.
  • Step 6: Test pH prior to planting to ensure amendments have improved soil pH.
  • Step 7: Plant crops. Monitor crop performance, and harvest results with a view to understanding impact of lime treatment.
  • Step 8: Following harvest, test soil pH again.

Application of lime can be part of an Integrated Soil Fertility Management (ISFM) practices.

While a practical solution, this soil amendment should be informed by research and discussion with extension officers and lime suppliers. On-farm storage and management of lime should be included in this dialogue.

Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Significant increases in productivity.
Increase Resilience
Sustainable improvements to soil fertility. Application is not required every year.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_05_AddingLime_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Lime treatment can assist farmers to balance pH in acidic soils, optimising water and nutrient use for crop plant growth.
  • A practical and effective way to combat the negative effects of erosion, compost decomposition and leaching on soil.
  • Lime does not need to applied to soil every year.

Drawbacks

  • Adding lime to soils is laborious and should not be considered a short-term solution to balancing soil pH.
  • Over-application or overuse of lime can negatively affect soil quality.

Organic Fertilisers

Value Chain
Soils
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

Soil fertility is one of the most critical factors needs to be maintained so farmers can continue to grow productive and nutritious crops, especially in southern Africa where soils are often fragile and lacking in plant nutrients. Soils are often quickly depleted if mismanaged, further exacerbated by natural biophysical processes such as rain, wind and/or heat. The use of organic fertiliser can help farmers to improve soil fertility, as they improve absorption of water and add nutrients into the soil, drastically improving crop production. Organic fertilisers are plant (crop residues) or animal-based materials, such as green manure, worm mouldings, compost, animal waste, and sewage residues, many of which may be readily available on the farm, or within a farming community. These products are potential counters to inorganic fertilisers - artificially manufactured chemicals (synthetic) mined from mineral deposits comprising minerals such as nitrogen, phosphorus and magnesium - which are often costly when few farmers can access credit needed to sustainably access such materials. Organic fertilisers are considered climate smart as they utilise (recycle) readily available organic materials to feed soil and crops simultaneously as they add nutrients into the soil and condition it, and thus increase productivity and resilience, while inorganic fertilisers add nutrients to the soil only, and are often expensive.

Technical Application

Organic fertilisers can be produced at the household level or purchased. On-farm production includes stock-piling animal manure, crop residues, and other organic waste, following appropriate guidance for processing and usage.

To apply organic fertilisers the following should be considered:

  • Step 1: Assess field area where fertiliser is to be applied, and fertiliser needs – poor crop performance, low organic matter content, etc.
  • Step 2: Ensure that fertiliser is available in sufficient quantities for application in all target or priority fields.
  • Step 3: Ensure organic fertiliser – especially green manure/crop residues – are broken-down/chopped to aid breakdown/integration with soil.
  • Step 4: Monitor soil nutrient levels and crop performance (in the light of prevailing climatic conditions) to determine success of organic fertilisers.
Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Household Workload
Food Security
Soil Quality/Cover
Biological Diversity
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Improves efficiency and crop yields.
Increase Resilience
Greater production and efficiency results in increased food security and resilience.
Mitigate Greenhouse Gas Emissions
Locks more carbon in the soil and reduces need for inorganic fertilisers.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_04_OrganicFertilisers_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Fertilisers can help restore soil nutrients, improve soil conditions and improve crop production if applied correctly.
  • Organic fertilisers are plant or animal materials that can be produced locally or purchased for application.
  • An appropriate strategy in rural and low-income communities with small holder farmers that can generally not afford synthetic pesticides and inorganic fertilisers.
  • Collective action can minimise the financial cost of implementing organic fertilisers, in terms of shared transportation and storage costs, as well as bulk purchasing power.
  • Use of organic fertilisers can help avoids the leaching of inorganic fertilisers into waterways, which can result in eutrophication.
  • Where farmers do have access to financial resources and/or credit, organic fertilisers should be used in combinate with inorganic application.

Drawbacks

  • Manure and other types of organic fertilisers require management, and relevant storage mechanisms. If not stored correctly, investment can be lost as nutrients can be lost due to exposure to the elements.
  • It can be costly to transport if sourcing from off-farm
  • Weed seeds can be present in manure, increasing labour requirements for weeding.
  • If not produced on-farm, organic fertilisers, while beneficial can require access to sustainable financial resources or credit to implement correctly.
  • Requires extension support to ensure that fertiliser requirements are being met.

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

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Mechanisation
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Maintenance Costs
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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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