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Supplemental Irrigation

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

Supplemental irrigation (SI) , also referred to as  Deficit Irrigation, is the application of water below full crop-water requirements, generally in drylands to assist crop growth in areas that experience low rainfall (300-500 mm/year). Supplemental irrigation involves adding limited amounts of water to rainfed crops to improve and stabilise yields when rainfall is insufficient for plant growth. Supplemental irrigation is a valuable and sustainable production strategy in dry regions or when experiencing irregular climatic conditions. This practice requires understanding of the yield response to water and the economic impact of loss in harvest. The aim of this technique is to ensure that the minimum amount of water is available during critical stages of crop growth.

Technical Application

To effectively undertake deficit irrigation:

  • Step 1: Determine critical growth cycle of desired crops.
  • Step 2: Experiment with SI strategies to determine critical watering times prior to upscaling.
  • Step 3: Strict management is required to determine the level of transpiration deficiency allowable without significant reduction in crop yields.
  • Step 4: Farmers capable of implementing deficit irrigation must have access to the minimum required water to implement deficit irrigation.
  • Step 5: Farmers must have access to a reliable water source, irrigation systems, including water distribution system, sprinklers and/or drip irrigation system.
Return on Investment Realisation Period
Crop Production
Fodder Production
Farm Income
Food Security
Soil Quality/Cover
Biological Diversity
Flooding
Crop/Livestock Water Availability
Wind Protection
Erosion Control
Increase Production
Stabilises yield.
Increase Resilience
Adapts to real time rainfall conditions.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_23_SupplementalIrrigation_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Increase crop production in dry areas or those experiencing drought.
  • Assist farmers manage crops at optimal times (low rainfall).

Drawbacks

  • Farmers must have access to enough water to meet minimum water requirements.
  • Require water distribution system that is functional.
  • Close management of crops to ensure that SI is implemented at critical crop production moments.

Solar Irrigation

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

Solar irrigation systems utilise solar energy to pump water to fields and distribute it through drip irrigation or other systems. Solar irrigation is a low-emission agricultural technology that replaces fossil fuel irrigation pumps reducing greenhouse gas emissions. This approach has the potential to reduce energy costs for irrigation and provide energy independence in rural areas. It provides opportunities to increase productivity by shifting from rainfed to irrigated agriculture in some areas. Solar irrigation systems require intensive management and regular monitoring to ensure the sustainable use of water resources. It requires maintenance of solar panels and irrigation equipment but can quickly yield a positive return on investment. Solar irrigation can be implemented for crop irrigation and livestock watering schemes and can improve food security, produce high value crops for sale, reduce energy costs and drive rural development. Although an expensive technology, solar irrigation can introduce significant operational savings if managed and maintained appropriately. It is considered a climate smart option as it can increase productivity, enable farms to adapt t climate changes and improve resilience, and the use of solar power reduces the use of on-grid, or diesel generator power, reducing emissions.

Technical Application

To effectively implement solar irrigation:

  • Step 1: To determine the solar pump system Crop water requirements, location, water sources etc. Do required research. Is water sourced from an above ground or below ground source?
  • Step 2: Source required materials to implement a solar irrigation system from regional or international suppliers including:
    • Photovoltaic (PV) panels to generate electricity (80-300 W system depending on context);
    • a structure to mount the panels;
    • a pump controller;
    • a surface or submersible water pump; and
    • a distribution system or storage tank for water.
  • Step 3: Identify funding sources as initial costs, as well as maintenance costs, must be considered and modelled prior to purchasing a system. There are regional and international solar irrigation producers.   These costs differ dramatically given the complexity of the context, starting at costs approximately USD $2,400 for equipment only. If drilling is necessary the cost increases significantly depending on depth, substrate etc.  Community-based investment, micro-leasing and rental services can be possible funding models to explore.
  • Step 4: Determine whether there is sufficient solar irradiation for the proposed area – consult and specialist; and/or the national meteorological service.
  • Step 5: Identify area suitable to install solar panels. The area should be easily accessible, and all trees/bush should be cleared. To determine most appropriate site and angle of panels, etc, consult an expert.
  • Step 6: The availability of technical expertise must be considered before implementation to ensure that any technical issues do not result in long period of service disruption.

Maintenance costs and expertise should be considered before installing solar irrigation systems. A detailed cost benefit analysis is advisable. Other key technical considerations include: Legal permits to extract water from the source as water extraction may impact community watershed levels.

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
Plants get enough water. Potential for two or more cropping seasons per year.
Increase Resilience
Predictable yields. Higher production equals increased food security/income and resilience.
Mitigate Greenhouse Gas Emissions
Significant reductions in CO2 emissions compared to grid and diesel-fuelled systems.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_22_SolarIrrigation_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Energy independence will introduce significant cost savings for farmers.
  • Solar powered irrigation can significantly boost productivity, due to increased ability to sustainably irrigate crops.
  • Consistent irrigation can help to mitigate climate impacts, and aid adaptation.
  • Reduces operational costs for diesel or on-grid power to pump water.
  • Reduces greenhouse gas emissions.

Drawbacks

  • Solar irrigation is expensive to implement and there are costs for maintenance. Therefore, savings or access to credit will be required.
  • Access to solar equipment, spares and parts, and the transportation of the above may be complicated and/or expensive.
  • Over and above cost and access technology, other issues such as access to land and water sources are important factors.

Saving Seeds

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

The process of saving one’s own seed involves the collection of seeds from the best performing (most yield, largest size, early maturing or other desired traits, etc.) plants from one season to plant them in the next cropping season. The aim of this practice is to select seed from parent plants in the hope that desired characteristics are replicated in the next generation of plants. Seeds that have been selected will likely be adapted to local farming conditions including soil types and rainfall amounts. The seed most likely to carry intergenerational traits (size, colour, water use efficiency, and other biophysical traits) are open-pollinated (those plants pollinated by birds, insects, wind, etc.) seed varieties as they are cross-pollinated by the same type of crop. Different crops have different reproduction cycles with some species flowering or producing seeds annually, biennially or on a perennial basis. Thus, understanding seeding time is important for farmers aiming to save their own seeds. Almost as important as selecting the correct seeds is seed storage, which must be done correctly to avoid spoiling and losses. Seed saving is a cost-effective measure for farmers to employ and helps them avoid having to buy seeds at market on an annual basis. Seed trading or community seed banks provide a climate resilience strategy as they secure farmers access and availability of diverse, locally adapted crops and varieties while enhancing indigenous knowledge. Often crops from hybrid seeds or improved varieties do not generate viable seeds ensuring that seeds cannot be saved and must be purchased on an annual basis.

Technical Application

To effectively undertake seed saving:

  • Step 1: Communicate with national agricultural extension and local farmers regarding seed harvesting timing and practices for local crop species.
  • Step 2: Clear field and sow desired crop using climate smart agriculture practices.
  • Step 3: Monitor plant life cycle and ensure that seeds are extracted correctly and are not spoiled in the process. Employ local expertise to ensure seed harvesting is carried out correctly.
  • Step 4: Post-harvest, seeds should be adequately dried and then transferred to proper storage facilities.
  • Step 5: store seeds in dry, cool, and dark locations. This will prevent them from spoil. Different strategies for seed storage are implemented around the region so local expertise should be sought.
  • Step 6: Ensure that pests are excluded from storage areas to prevent loss or spoil (Technical Brief 61-65).
  • Step 7: Community seed banks or seed trading should be established to allow farmers to integrate different varieties into their farming system that are resilient to local climatic conditions
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
Can reduce losses from pests and diseases.
Increase Resilience
More predictable yields.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_21_SavingSeeds_2019-10-17_0_0.pdf
Benefits and Drawbacks

Benefits

  • Climate resilient method for crop diversification.
  • Many farmers have been using this technique for generations and this should be encouraged.
  • Cost effective method for sustainable crop growth.

Drawbacks

  • Attention must be closely paid to plant lifecycle and seeds should be collected at appropriate time.
  • Storage methods should be employed to manage pests and rot.

Crop Variety Selection

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

Selecting crop varieties is a key resilience strategy for farmers facing changing climatic conditions. There are two types of seed varieties: traditional varieties and improved varieties. Traditional varieties have been selected by farmers for their special characteristics and due to many years of selecting the strongest seeds over generations, they are generally adapted to local natural conditions. In some respects, these seeds increase the chance of getting a return on investment in stable environments, but are less likely to mitigate GHG emissions. Traditional crop varieties are usually selected by small scale farmers due to their relatively low cost and availability and can be saved and replanted for further growing seasons. Improved varieties are seeds that have been altered by scientific processes to incorporate desired characteristics using techniques such as following pure line breeding, classical breeding, hybridisation and molecular breeding. Desirable characteristics include higher yields, shorter growing seasons, drought resistance, salt tolerance, etc. Improved varieties are selected when facing adverse conditions such as higher temperatures and/or less predictable rainfall and normally result in the efficient use of water reducing use of energy for irrigation systems. While these seeds offer improvements they are usually commercial products and as a result can be expensive. Furthermore, as they are sold by seed companies availability is driven by demand. Most seed companies protect enhancements using  intellectual property rights that legally limit seed saving and replanting of seeds. In fact, many of these seed varieties have been designed to prevent plants to be reseeded. Thus, seed varieties afford farmers the opportunity to incorporate crops that can be planted to exploit their unique characteristics – traditional or improved, assisting farmers to grow crops that are resilient to changing climates to produce crops that are market-appropriate.

Technical Application

To effectively undertake leverage traditional seed characteristics, or improved crop varieties  the following should be carried out:

  • Step 1: Prior to selecting seed varieties, perform a Cost Benefit Analysis (CBA) to identify how crops will perform and their benefits compared to the costs of the seed, considering the following:
    • Local  farming system(s): land availability per household, crops traditionally grown, access to inputs such as fertilisers,
    • Local environmental conditions: soil conditions, disease, pests, climatic conditions, occurrence of flooding/droughts and other natural disasters.
    • How climate change has impacted or will impact the farming system and how crop variety selection can be a climate- smart practice.
    • Local access to seeds – is seed collected at the householder level, do neighbours exchange seeds, do farmers have access to commercially produced seeds?  Are the costs for accessing commercial, improved seeds manageable or prohibitive? The CBA should weigh the benefits of a new seed against perceived actual or transactional costs for selecting a new seed.
  • Step 2: Obtain information and guidance from local experts, lead farmers, and government regarding best varieties to grow.
  • Step 3: Evaluate results of the CBA and select appropriate seeds that match the farm system/requirements, and available financial resources/access to credit.
  • Step 4: Plant test plots of selected seeds to understand if benefits are realised and demonstrate outcomes with farmers, showing possible alternatives and discuss implementation.
  • Step 5: Following full demonstration and discussion with farmers, implement at farm level – planting the first crop in accordance with guidance provided by seed provider, or traditional knowledge.

Consider in-country seed sources to access different varieties through local extension or research services. When buying seeds ensure that the seeds are adequately dry and look for seed that is certified by a national seed laboratory to ensure that the variety is the highest quality possible. Seeds should be properly stored to avoid high temperatures and humid air to reduce chances of early germination.

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
Selecting improved seed varieties allows the farmer to maintain agricultural productivity as the climate changes.
Increase Resilience
Selection of improved varieties may assist farmers adapt agricultural production to assist adaptation to climate change.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_20_CropVarietySelection_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Exploring crop variety is a key way for farmers to grow more resilient crops within the context of changing climatic conditions. Drought resistant or faster maturing varieties, for example, allow you to respond to reduced rainfall conditions.
  • Improved crop varieties have been altered by scientific processes to incorporate desired characteristics.
  • Understanding local context is important when researching the best crop variety for the area.

Drawbacks

  • Improved crop varieties are commercially sold and can be expensive as they often require additional inputs (inorganic fertilisers etc.)
  • Traditional crops have generally adapted to local climatic and landscape conditions, are widely available and are cost effective for local populations; however, these varieties may not be resilient to climatic changes, and are less likely to mitigate GHG emissions.

Weed Control

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

Weeds are any unwanted plant species that compete with crops for sunlight, water, nutrients, air and space, hindering crop growth and in some cases are even toxic to crop plants. Weed control measures can be applied in an integrated manner to help prevent the growth and spread of weeds in agricultural systems. An integrated weed management approach aims to restrict weed growth until a crop is well established and can outcompete weeds. This integrated approach includes biological, chemical, cultural and/or physical tactics to combat weed spread and growth and these practices can be more cost effective than herbicide applications. Integrated weed management is climate smart as it combines multiple climate smart practices that increase farmers resilience, limits GHG releases and increases productivity. Options for weed control include crop rotation, intercropping, cover crops (which can be used as green manure or mulch), mulching, seed-bed preparation, livestock grazing, seed/variety selection, mowing, and hand-weeding.

The application of integrated weed control is climate smart as it reduces herbicide application and reduction in machinery usage (i.e. through no-tillage practices).

Technical Application

To effectively undertake weed control measures:

  • Step 1: Review weed control measures - crop rotation, intercropping, cover crops, mulching, seed-bed preparation, livestock grazing, seed/variety selection, mowing, hand-weeding and adjustments to tillage practices - and determine which methods are available and appropriate for the farming system and farmer. Two or more of these techniques can be applied to assist in ensuring farmers have more chance of success. Understand possible negative impacts of each weed control method.
  • Step 2: Improve weed identification knowledge in specific areas.
  • Step 3: Prevent weeds from spreading – clean clothes, animals, machinery, vehicles to limit weed transport; use only well stored/rotted manure (4-5 months) (Knowledge Product 16), include fencing, irrigation and other farm ‘breaks’ where possible
  • Step 4: Apply a combination of weed control methods including – cover crops (Technical Brief 15), mulching, intercropping (Technical Brief 07), crop rotation (Technical Brief 09), livestock grazing, seed selection (Technical Brief 20), mowing, hand-weeding. Try to avoid the application of herbicides, tillage and burning.
  • Step 5: monitor and document most effective weed management strategies for each farmer, and use lessons learned from the area with other farmers where applicable.
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
Weed control supports agricultural productivity by removing competition while reducing the need for herbicides.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_19_WeedControl_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Integrated weed management involves employing two or more climate smart practices.
  • Reduced consumption of chemicals
  • Cost effective methods that do not require additional inputs.

Drawbacks

  • More time consuming than applying herbicides or other more destructive methods.
  • Strategy requires careful planning.
  • May not be 100% effective.

Erosion Control

Value Chain
Topography
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

Erosion control measures are practices designed to reduce runoff water and wind erosion that wash away top soil and nutrients, degrading soil biodiversity and reducing agricultural productivity. Erosion is a natural, biophysical process resulting from rainfall, water flows, wind, or storm runoff. Erosion is integral to the formation of soils, however human and animal activity, including agriculture and clearing of land, can accelerate erosive processes, drastically impacting landscapes, soils (e.g. quality) and watercourses. In addition, erosion control measures can contribute to reducing rainfall runoff, increased water infiltration into the soil, and attenuates flooding. The intensity of rainfall is directly correlated with the severity of soil erosion; hence, this is a significant problem across the Southern African region as much of the rainfall in the region is episodic, and intense. To prevent or reduce erosive processes control measures can be incorporated into farming systems to reduce or reverse degradation and potentially restore or improve soil quality. Erosion control measures aim to mitigate soil erosion and improve soil fertility by reducing flow and speed of run-off to avoid soil being washed away. Erosion control can be initiated through a number of interventions, including, but not limited to, intercropping (e.g. planting cover crops), mulch, conservation tillage and reforestation, as well as terracing, soil bunds, etc.. Example: Stone Bunds. Lessons learned from West Africa show that stone bunds constructed along contour lines in fields and in key run-off locations can significantly reduce run-off, particularly in steeper agricultural fields. The stone lines reinforce the soil structure in the field following the contours of the land, reducing the speed and volume of run-off, thereby reducing the likelihood of erosion. This is an appropriate technology to implement on slopes up to 15 to 20 degrees. This is considered a climate smart practice as it maintains soil structure and nutrients, in turn retaining carbon in soil, enabling farmers to adapt to climate changes and sustain agricultural productivity.

Technical Application

Without a topographic survey, this technology may require trial and error to begin with, to see how rainfall and run-off responds to the contouring. To effectively implement erosion control measures the following should be carried out:

  • Step 1: Perform a thorough local study of the landscape, soils, land use and erosive processes that most impact the area: steep slopes, flood plains, high winds etc.
  • Step 2: Source a large number of stones, preferably five to ten centimetres square blocks (from a quarry) or five to ten-centimetre diameter cobbles (from a river-bed). You will need 30 to 50 tonnes of stone per hectare for contour bunds approximately 300 metres long.
  • Step 3: Mark out contours, as discussed in Technical Brief 16 Contour Planting.
  • Step 4: In larger fields with shallower slopes, place stones in rows of two along contour line, interlocking alternately, burying the lower half. The bunds can be between 25 and 40 metres apart. On steeper slopes, stack and bury stones against or in vertical/near vertical walls of contours much closer together (five to ten metres apart) to reinforce them.
  • Step 5: Make sure that stone bunds follow the contours from one side of the field to the other, ensuring that no ‘pour’ points (larger gaps) exist along the way, lining the drainage channel or weir from one contour to the next with stones to avoid or reduce scouring in these locations.
  • Step 6: Following, and if possible, during rainfall events, check the stability of the slope, adjusting stone bunds where necessary.
  • Step 7: At the end of the rainy season and again following harvest, review the performance of the technology, and prepare for the next growing 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
Increased water infiltration can extend growing period and mitigates short dry spells. Can reduce flood risk downstream.
Increase Resilience
Increased production due to improved nutrient availability and higher nutrient use efficiency.
Mitigate Greenhouse Gas Emissions
Depending on practices used, may lock more carbon into the soil.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_11_ErosionControl_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Erosion control measures prevent the loss of top soils and nutrients.
  • Can help farmers adapt to changes in climate that have include increased rainfall amounts and intensity.
  • Can reduce the impact of wind erosion.

Drawbacks

  • Erosion is a natural process that can be increased due to human and animal activity.
  • Requires substantial labour inputs to construct bunds and other erosion control measures
  • Maintenance is also needed.

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.
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