Table 1 Summary of ex situ and in situ approaches, the soil health constraints and farmers’ production and household constraints they can address and the relevant farming systems
Input/approach | Soil health constraint addressed by the input | Farmers’ production and household constraints addressed by the input | Trade-offs and constraints |
|---|---|---|---|
Ex situ | |||
Livestock manure and compost | Soil acidity; declining SOM; nutrient deficiencies; nutrient imbalances; Al and Fe toxicity; poor soil water content/permeability | Declining crop productivity; lack of cash to buy synthetic fertilizers | Availability and shortage due to its multiple uses; spread of weeds; GHG emissions; labour for transporting and applying; low nutrient content |
Biomass transfer (agroforestry) | Declining SOM; nutrient deficiencies; nutrient imbalances; poor soil water content/permeability | Declining productivity; shortage of livestock fodder | Shortage due to its multiple uses; labour for transporting and applying |
In situ | |||
Crop residue retention | Soil erosion; soil acidity; declining SOM, reduction in temperature, reduced evapotranspiration, poor water infiltration | Declining crop productivity; loss of topsoil, heat and drought stress | Low livestock productivity (competition with use as livestock feed); temporary reduction in maize yields due to N-lockup; GHG emissions; open grazing; change in farmer practice |
Intercropping with grain legumes | Declining SOM; N deficiencies; pest and diseases build up; poor water infiltration | Declining landholding size; declining crop productivity; dietary deficiencies; weed problems; poor food nutrient diversity | Nutrient mining; crop competition; land use change |
Rotation with grain legumes | Declining SOM; N deficiencies; soil-borne diseases; pest and diseases build up; poor water infiltration | Declining productivity; dietary deficiencies; shortage of protein-rich food; weed problems; poor food nutrient diversity | Nutrient mining; large land requirement |
Rotation with green manures legumes | Declining SOM; nutrient deficiencies; nutrient imbalances; pest and diseases build up; soil borne diseases; poor water infiltration | Declining productivity; weed problems | Land not used for food production; labour and machinery requirement to incorporate into soil; knowledge intensive to target |
Agroforestry: Intercropping | Declining SOM; nutrient deficiencies; nutrient imbalances; soil acidity; pest and diseases build up; poor water infiltration | Declining productivity; lack of cash to buy fertilizers; weed problems; poor food nutrient diversity | Labour for trimming and soil incorporation; knowledge intensive; time to establish |
Agroforestry: Rotations | Declining SOM; nutrient deficiencies; nutrient imbalances; pest and diseases build up; soil acidity | Declining productivity; lack of cash to buy synthetic fertilizers; shortage of fuel wood; shortage of livestock fodder; weed problems | Land not used for food production; labour for clearing fallows and soil incorporation; knowledge intensive; time to establish |
