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Alternate Wetting and Drying

Value Chain
Annual Average Rainfall
Soils
Climatic Zone
Water Source
Altitudinal 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

Alternate wetting and drying also called intermittent flooding is a technique developed by the International Rice Research Institute (IRRI) to control water consumption in rice fields (CGIAR 2014). This technology saves water throughout the year in areas of variable rainfall. It is designed as a pick-up water system in cases when water consumption is cut. Water levels are monitored and controlled by the removal of excess water, leaving enough water to sustain crops. Alternate wetting and drying reduces greenhouse gas emissions especially methane, which is emitted from flooded rice fields (FAO 2016). The drying phase helps to sustain and develop plant roots. Moreover, costs on fuel used for irrigation are reduced.

Technical Application

To effectively implement Alternate Wetting and Drying practices:

  • Step 1: Alternate wetting and drying should be considered by the farmer after two weeks of rice transplant.
  • Step 2: The farmer should consider digging half of 30 cm tube into soil to monitor water level.
  • Step 3: When the water level is 15 cm below the soil surface the field should be irrigated again with a depth of 3 to 5 cm before water drains.
  • Step 4: This cycle should be repeated until flowering stage to avoid disturbing reproduction because at this stage the crops are sensitive to water stress.
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
Cost of production reduced through less use of water.
Increase Resilience
Maintain production with reduced inputs. Predictable yields.
Mitigate Greenhouse Gas Emissions
May reduce GHG emissions from irrigation pumps.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_31_AlternateWettingandDrying_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Alternate wetting and drying maintains rice yields in areas with variable rainfall/irrigation water supply.
  • Reduces greenhouse gas emission such as methane.
  • The technology can be carried out in regions prone to heavy rainfall.

Drawbacks

  • Water levels need to be monitored carefully to avoid water stress which might decrease yield.
  • Not recommended in areas with potential salinity stress as reduced water inputs might aggravate salinity levels and cause yield decline.

In Field Water Harvesting

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

In-field water harvesting is the practice of increasing water infiltration and moisture retention in the soil. The agricultural technique involves the collection of rainwater runoff from fields that is collected and stored for future needs. This water can be stored in infiltration pits and later used to water the same crops, other crops through an irrigation system (usually high value crops, including fruit trees), or used for domestic purposes. Factors like soil, water, and plant type influence the effectiveness and productivity of rainwater harvesting. This type of water harvesting is generally implemented in areas of very low rain (semi-arid) conditions. In-field water harvesting entails establishing micro-catchments at the farm scale, where sloped areas have been cleared or cropped to direct rainwater to the water storage area (a pit that has been dug to store/hold water). Utilising strip cropping to growing crops while providing a method for directing rain is sometime practiced. The soil type has a limiting factor in collecting in-field water due the infiltration rates. In-field water harvesting saves rainfall water that can be used over a longer period than during and immediately after a rainfall event, reduces the risks of crop failure due to no or limited rainfall, and increases rain water productivity.

Technical Application

To effectively In Field Water Harvesting techniques, the following steps should be carried out:

  • Step 1: Land is cleared, berms are developed, and crops are planted in order to direct water to the infiltration point.
  • Step 2: The catchment areas should be sloped no more than 5 % and the area should be cleared to promote catchment as much as possible.
  • Step 3: The infiltration pit (where water is stored) should be dug at the lowest point of the catchment areas and line infiltration pits with plastic or concrete roofing to limit water loss, and can be used as a source of irrigation for fruit trees and other high value crops.
  • Step 4: Paths can be built of soil to guide water to the infiltration pit.
  • Step 5: Alley cropping, or strop cropping can be used, with areas between trees and crops dug deeper like a trough to direct water to the infiltration pit.
  • Step 6: To access water from infiltration pits, farmers can introduce a pumping system and water can be distributed around the farm as 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
Water is available to plants when it is needed. Reduced nutrient leaching.
Increase Resilience
Mitigate dry spells.
Mitigate Greenhouse Gas Emissions
Can lock more carbon in the soil. More efficient use of fertilisers.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_25_InFieldWaterHarvesting_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Harvested water used in irrigation systems.
  • In-field water harvesting saves rainfall water that can be used over a longer.
  • Reduces the risks of crop failure due to no or limited rainfall.
  • Increases rainwater productivity.

Drawbacks

  • Major issues with a dug-out infiltration pit is evaporation and seepage. Evaporation can be combated by the addition of mulch to water and seepage can be prevented by including some kind of liner (plastic sheet, concrete, etc.). In addition, large plastic, steel or concrete container can be built or sunk below surface to prevent major seepage. Roofs can be built over infiltration pounds or built containers to limit the loss of water to evaporation.

Drip 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

Drip irrigation is a method of slow delivery of water to crops, through highly-controlled flow management, applied along the soil or at the sub-surface level directly to crop root systems. Drip irrigation is an effective system for conserving water while ensuring that it is used optimally without losing it to evaporation through high efficiency water delivery. Drip irrigation involves establishing a network of tubes, values and pipes connected to water source by a pump, along crop rows. A water source is required which is a drawback as many dryland areas lack these water sources. Drip irrigation is a climate smart option as it increases farmer resilience to the effects of climate change.

Technical Application

To effectively implement drip irrigation:

  • Step 1: A reliable water source must be available - natural (natural or through rain-water harvesting).
  • Step 2: Acquire a pump system (approximately $US 100) that maintains enough pressure to deliver water through the system or an elevated tank.
  • Step 3: Connect lines or hoses and laterals that run from the pump system across the planted fields.
  • Step 4: Run lines or hoses with emitters (drippers) or small punctures at the surface level along planted crops or just below the surface providing water to the roots system of the plants.
  • Step 5: Once the system is operable, the pump can be turned on and water dispersed as required by the nature of the crop and can also be implemented with supplemental irrigation strategies (Technical Brief 23).
  • Step 6: Monitor the irrigation system regularly to ensure there are no malfunctions and the system is maintained. Crops that receive regular water can develop shallow root systems and any prolonged disruptions in service could have   significant impacts.
  • Step 7: If applying drip irrigation in sloped conditions, follow the contours of the slope as outlined in Technical Brief 16.

Once a drip irrigation system is up and running, farmers can explore fertigation, the addition of soluble fertilisers into the irrigation system water for distribution directly to plants.

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
Energy saving.
Increase Resilience
Increase crop yield.
Mitigate Greenhouse Gas Emissions
Continued production in changing environments.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_24_DripIrrigation_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Maximises efficiency in crop irrigation in dryland or variable climate conditions.
  • Minimizes the loss of water to evaporation.

Drawbacks

  • Requires consistent water source.
  • Costs of establishing the system, pump and lines/hoses can be significant depending on configuration, etc.
  • Requires continual monitoring and may need regular maintenance.

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.

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.

Terracing

Value Chain
Annual Average Rainfall
Soils
Topography
Climatic Zone
Water Source
Altitudinal 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

Terraces are cross-slope barriers that have been cut into slopes offering surfaces that are flat or slightly sloped. Terraces are designed to minimise erosion and increase the infiltration of runoff water. In addition, terracing allows for a maximum of area for farming and cropping by cutting into slopes, creating steps on a hillside. Riser walls are retained by growing trees or grasses, using stones or compacted soil to manage runoff and ensure stability. Terracing involves significant planning and labour to implement and maintain. Labour should be coordinated and planned to ensure that terracing is not carried out in an ad hoc manner, and labour to maintain the terraces is available annually. Terracing is suited to areas with severe erosion hazards, deep soils, on slopes that do not exceed 25 degrees and are not too stony. Community action is often required, as terracing is a landscape-level solution that can only be implemented if all parties agree and convert slopes together. Implementing individual terraces or terraced sections can negatively impact the entire hillside.

Technical Application

To effectively approach to terracing construction:

  • Step 1: Measure slope angle – should not exceed 25 degrees and soils should be at least 0.5 metres deep.
  • Step 2: Plot the contours – see Technical Brief 16 Contour Planting for instructions for staking-out contours, and the diagram below for use of a t-stick to measure the distance between contours.
  • Step 3: Start at the lowest terrace. Dig a trench vertically below the next contour, and then dig outwards to the lowest contour. Remove soil and place downhill below the lowest contour.
  • Step 4: Compact soil on constructed terrace.
  • Step 5: Work should then progress upslope, emptying top-soil on to the terrace below to provide soil for planting.
  • Step 6: Strengthen riser buttress walls (back-walls) with stones, compacted soil, or by planting grass or trees.
  • Step 7: Terrace-end drainage should also be considered, so water does not pool too heavily. The down-field gutters can be lined with stones to reduce erosion

Detailed diagrams and tables for calculating terrace dimensions are provided in Peace Corps 1986, Soil conservation techniques for hillside farming.

Additional guidance can be sought from videos provided by Access Agriculture: SLM02 Fanya Juu terraces. The Kenyan example provided is also up-slope terrace construction but using a different method where a trench is dug, and the loose topsoil is thrown up-hill (fanya juu in Kiswahili) which forms a ridge that flattens over time.

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
Stable slopes are a critical element of maintaining agricultural productivity.
Increase Resilience
Terraces enhance slope stability and reduce soil erosion in the face of changing climates, with changing temperature and rainfall regimes.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_18_Terracing_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Terracing prevents erosion and can act as a rainfed irrigation system.
  • Terracing is a labourious process to implement and takes significant effort to maintain.

Drawbacks

  • Requires professional advice on implementing terracing.
  • If implemented incorrectly, can have negative impacts including more erosion than without terracing.

Agroforestry: Alley Cropping

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

Agroforestry is a land management practice that combines the planting and management of trees and shrubs with crops and pasture, providing benefits of soil health, crop yields, resilience to climate change, biodiversity and economic opportunities. Agroforestry encompasses numerous practices, including silvo-pasture, agro-silvo cultural, and agro-silvo-pastural. One successful agro-silvo-cultural practice is alley cropping, where the farmer plants rows of trees, shrubs or hedges between crop rows. Usually hedges comprise leguminous plants intended to fix nitrogen in the soil and provide leaf litter and prunable biomass. The hedges are pruned with the pruned material spread on the ground, to reduce shading and competition with the primary crop. Timing of pruning is important to ensure that the pruned biomass releases nutrients to the soil at a time when the primary crop needs them for maximum crop productivity; e.g. when alley-cropping maize, the pruned biomass needs to breakdown with and release beneficial nutrients into soil from two and eight weeks after planting the maize crop. This approach has proven to be highly successful, with examples in Malawi where gliricidia was alley-cropped with maize where the prunings created a three-fold increase in maize production, which was increased a further 29 % when fertilisers were added. This fertilisation could be achieved with green manure, and other climate smart soil amendment approaches. The space and number of hedge rows to primary crop is dependent upon the field size and the regular growth height of the shrub/hedge. The hedge must not be planted so close that it shades the primary crop. In larger fields, larger deep-rooted timber trees can be planted between groups of rows of primary crop, providing soil benefits, reducing wind-speeds/erosion, and providing timber products.

This approach is considered climate smart as it increases productivity, provides a mechanism for more climate resilient farming, whilst increasing soil carbon levels.

Technical Application

While agroforestry practices are deemed highly beneficial and climate smart, it is important to ensure that proposed practices are appropriate for the specific context – the benefits of the agroforestry practice match the needs of the farmer - and are fit for purpose. Obtain advice from an agroforestry expert before embarking on secondary crop/hedge species selection.

To effectively implement alley-cropping the following should be carried out:

  • Step 1: Clearly understand the objectives of the intervention and identify an appropriate species for intercropping. For maize and sorghum in a smaller subsistence farm setting, selection and growth of hedge rows of a legumes such as cowpea or Gliricidia can provide sustainable benefits in terms of soil quality and secondary fodder/food products. In larger fields, timber trees can be planted every five to ten crop rows, depending on the height of the mature tree, and the shade-tolerance of the crop.
  • Step 2: Identify and understand key conditions, such as prevailing wind direction, and sunlight to ensure that the field is planted in an appropriate configuration, with primary crop and secondary (hedge/shrub/tree) crops planted in such a way as to benefit the primary crop and not compete with it. East to west row orientation should maxmise sunlight, topography permitting.
  • Step 3: For beneficial hedgerow growth with legume species such as Leucaena, cliricidia, and Sesbania sesban, the trees should be planted in rows between two and four metres apart, with individual trees planted as close as possible - between 10 to 15 cm apart. If planted closely, the trees will favour leaves over step growth, creating more mulch to prune for cover. Note that if rows are planted too closely, the secondary crop can dominate the available crop land reducing productivity. Furthermore, the closer the hedges, the more shade will present, which can depress crop growth, and also start to compete for soil water and nutrients, which is not beneficial.
  • Step 4: Once reaching sufficient maturity, after approximately six months (one-metre tall for legumes)– hedges should be pruned to generate mulch for working into the soil. Then the primary crop (maize) can be planted. Pruning once per month thereafter provides cover and ensures that light penetration is maintained. Planting legumes approximately six months before planting the primary crop can ensure that sufficient pruned material is available to incorporate into the soil to enhance growth.
  • Step 5: After harvesting the primary crop, hedgerows can be left to grow taller so that shade reduces weed grown, and to develop material to prune and incorporate into the soil again during the following crop cycle. However, hedges should not be allow to grow too high or dense as their roots will dominate the soil and out-compete primary crops for water and nutrients.

Before implementing any of these technologies, further research may be required beyond the guidance provided here. The World Agroforestry Centre (ICRAF) has many resources, toolkits and success stories that can support such research.

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
Alley cropping and pruning of leguminous hedges increases productivity of primary crops such as maize.
Increase Resilience
Helps farmers to be more resilient to climate change, by sustaining productivity and controlling soil health, especially when faced with changing climates.
Mitigate Greenhouse Gas Emissions
The planting of alley hedge rows of legumes and the introduction of pruned material contributes more carbon to the soil.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_17_AgroForestry_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Trees, shrubs, and hedges are incorporated into farming systems and have many different biophysical and socio-economic benefits.
  • Use of leguminous hedges no only provides pruned materials to provide cover, but they also help fix nitrogen in the soil.
  • Hedges planted in alleys can also provide other benefits such as edible seed pods for human or animal consumption.
  • Hedges and trees can reduce soil erosion from run-off or wind erosion.
  • Alley cropping can provide opportunities for diversified income – selling secondary crops and/or timber.
  • Alley cropped timber trees can provide building materials fire wood.

Drawbacks

  • Initial labour requirements will likely be significant; however, this will be primarily at the earlier stages of the intervention.
  • Ongoing maintenance such as pruning and maintenance of hedges will be needed, although relatively minimal.
  • There may be some costs involved in obtaining hedge seedlings.
  • Use of trees rather than hedges and shrubs introduces more labour, but yields more benefits.

Contour Planting

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

Contour Planting is a planting strategy for sloping fields, where crop rows follow slope contours rather than planting in rows up- and down-slope. The primary aim of this strategy is to slow the downhill flow of water and encourage the infiltration of water into the soil. Slowing the flow of runoff water reduces soil erosion and therefore also nutrient loss.

Contour Ridges are created by tilling, ploughing or hoeing soil to establish ridges along contour lines, acting as a barrier to downhill water runoff and other erosive processes - the higher the ridge height, the more effective the barrier is to preventing soil erosion.

Contour Strips involves use of vegetative barriers e.g. planting of strips of grass or hedges and other species to secure soil and further prevent erosion. These practices are labour intense and require extension support, especially as contour lines are not straight but follow slope characteristics, correctly identifying contour lines is important and can be done using the ‘low-technology’ options that are identified in the Technical Application section of this Technical Brief.

Technical Application

To effectively undertake contour planting:

  • Step 1: Construct an A-frame that has a plumb-line with a rock hanging down the centre. The base of the A-frame should be 90 cm.
  • Step 2: Calibrate the A-frame on flat ground. Ensure that both legs are on the ground. Mark where the plumb line meets the cross bar.
  • Step 3: On a slope, working perpendicular to the slope, plant one leg of the A-frame and swing the other leg around until the plumb line meets the mark on the cross bar. Drive a stake into the ground where the first ‘planted’ leg is and continue the process across the slope.
  • Step 4: Once the extent of the contour has been staked, tie a string from post-to-post across the slope; this identifies the contour to be planted.
  • Step 5: Plant selected crops, develop contour ridges or plant contour strips along the contour line.
  • Step 6: Subsequent contours should be spaced 3-5 m up or downhill of the preceding contour line. To determine the length between contour lines, measure off the top of each stake to a stake up or downhill with a tape measure or accurately measured third stick.
  • Step 7: Contour ridges can be implemented like Water Spreading Bunds (Technical Brief 28) to form ridges of soil that are formed by tilling or ploughing and can be left after land preparation to further prevent erosive forces. Crops can be planted between these ridges.
  • Step 8: The planting of contour strips can be implemented by planting grasses or hedges 20 m (shallow slopes) to 10 m (steeper slopes) apart up or downhill, similar to Trash Lines (Technical Brief 14). This intercropping allows for erosion control and can be used as fodder for livestock.
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
Retaining soil structure enables farmers, particularly those planting on sloping fields to maintain productivity.
Increase Resilience
This land management practice aid farmers to maintain soil structure in the face of changing climates and shifting rainfall patterns.
Additional Information
PDF File
/sites/secondsite/files/tb/CCARDESATechnicalBrief_16_ContourPlanting_2019-10-17_0.pdf
Benefits and Drawbacks

Benefits

  • Contour planting prevents erosion on sloped fields and efficiently trap runoff water.
  • Contour planting improved water infiltration and contour ridges improve water retention.
  • Contour planting can be integrated with intercropping contour strips of grass or hedges to help maintain soil structure.

Drawbacks

  • Contour lines are extremely labour intensive and take a significant amount of time to implement.
  • During contour measuring and development, land may be exposed to erosive forces.

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.
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