Maize

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.

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.

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.

To effectively undertake composting:

• Step 1: gather compostable materials - rests of harvests, animal manure and dung, organic kitchen waste (fruit and vegetable waste), other food waste, edible oils and fats, wood shavings, paper products (not printed), hair cut waste. Avoid non-compostable materials such as chemical residues, glass, metals, plastics, carcasses, cooked leftovers or meat.
• Step 2: Chop/cut materials to achieve optimum particle size is between 5 – 20 cm – this will assist decomposition. Wire mesh can be used to sift smaller non-organic particles.
• Step 3: Add water regularly using a watering-can to assist decomposition, ensuring that the materials do not become water logged.
• Step 4: Using a pitchfork or shovel, turn-over or rotate compost materials regularly as oxygen is a key component to the decomposition process.
• Step 5: If available, add earthworms (known as vermiculture) to compostable material, which enriches soil, enhances plant growth (hence yields) and suppresses disease.
• Step 6: Once compost material has been decomposed (three months to two years, depending on climate and composting material) it will be a fine, dark material. Screen the material to remove large particles and mix with soils in gardens or fields prior planting and around plants throughout growing period.
• Step 7: If compost does not include animal manure/waste it can be applied to crops as an organic fertiliser at any point up to harvest. If it does include animal waste, it can be incorporated into soil not less than 120 days prior to harvest, especially where edible portion of crops has been in contact with the soil surface.

Additional notes:

• For Open Composting System (Piles): select a level area or dig a pit with a level bottom away from developed areas, chop collected materials into piles, turn over or rotate and add water to material regularly (weekly or bi-monthly). Cover pile if there is heavy rain to prevent materials from washing away and becoming water-logged.
• For Contained Composting Systems: construct a container unit from mesh, wooden panels, bricks and other suitable building materials, fill the container with chopped material, turn over or rotate, and add water to material regularly (weekly or bi-monthly). Keep compostable material covered.