What is CA?
Click here for a Wikipedia page describing Conservation Agriculture (CA) in general.
On this page you'll find information about CA in the context of the small-scale farmer in sub-Saharan Africa. It's important to be specific, because CA can be applied across a wide range of environments, countries, scales and crops. The Barney Planter has been designed for use by ‘subsistence’ farmers with little or zero mechanisation.
Traditional planting of maize begins by turning over the soil by hand using a heavy hoe called a ‘jembe’. This is slow, hard work that frequently begins after the start of the rainy season, once the ground has softened a little.
This process exposes what moisture is left in the soil, which then evaporates; the loose soil is also subject to erosion by wind and, particularly, water. Seeds are planted by hand along a row using a machete (‘panga’) to dig a small hole at intervals — a slow process, but one that provides accurate planting.
Fertiliser can also be added to the hole at this stage, but seed ‘burn’ can occur if the fertiliser dissolves and the solution comes into contact with the seed. Fertiliser can instead be scattered across the surface as a ‘top dressing’, but this is wasteful: it also fertilises weeds, doesn't all benefit the crop, and is washed away during the typically heavy cloudbursts of the tropics.
During tropical downpours, raindrops impact heavily on the soil surface. This ‘splash erosion’ further loosens tilled soil, facilitating erosion, while also compacting the soil beneath each raindrop and scattering fine dust across the surface. That dust then clogs soil pores, forming a skin. The skin impedes water infiltration and, once dried, causes problems for emerging crops.
These are some of the issues Conservation Agriculture sets out to address. Unfortunately, there is very little help available for small-scale farmers who want to take up CA, as there are few, if any, useful tools they can use.
- Labour intensive
- Time-consuming
- Evaporation of soil moisture
- Delays in planting due to dry soil
- Excessive fertiliser requirements
- Fertiliser wastage
- Possible seed burn
- Soil erosion
- Poor water infiltration