To sustain your soils and fields rotate your crops intelligently; planting cowpea is a useful alternative in a rotation.
Cowpea is an important grain legume in sub-Saharan Africa and a source of cheap plant protein in the edible dry grains. Used as a vegetable, the young leaves, pods and green seeds are also edible.
It provides nutritious fodder for livestock and the fallen cowpea residues and roots contribute to soil fertility.
Legumes are often used as a rotation crop because of their nitrogen fixing ability. The cowpea can take 80% of its nitrogen needs from the atmosphere; nitrogen which ends up in the soil where it acts as a cost-free fertiliser for the farmer. When root nodules and leaf litter decay, residual nitrogen improves the soil. Farmers who plant cowpea can do with very little fertiliser for optimum production.
Cowpea is tough enough to handle marginal soils.
FROM MONO-CULTURE TO DIVERSITY
Maize cultivation is important in the southern region, but there are factors beyond the farmer’s control that put some risk into farming maize. The weather plays a critical role in dryland maize production and weather is a fickle partner, as farmers have often been reminded.
There are other threats like the recent fall armyworm invasion, that can bankrupt farmers through crop failure.
The maize price can be an equally untrustworthy player, with drastic drops in price when harvest is higher than usual.
These problems are linked to mono-culture known to be risky and linked to crop wipe-out and supply excesses. Countries like Gambia and Senegal, have suffered the risks inherent to the groundnut mono-culture regime. It’s not just maize that’s the problem.
Experience and observation teaches farmers ways to counter these risks. One of the most obvious solutions is to diversify.
The introduction of indigenous crops adapted to the environment is a diversification no-brainer. They can be produced with minimum input for maximum output.
As a hardy and drought-tolerant crop, cowpea is ideal for this niche. In circumstances where other cereals may fail, cowpea can maintain its grain yield.
When there is too much rain, it puts more growth into the canopy and delays flowering, producing a bigger fodder yield and about a 60% grain yield, depending on the type, or variety.
There are some high-yielding cowpea varieties with yield potential varying from 2t to 4t of grain, and 15t to 20t of fodder, per hectare, depending on the management.
Rotate maize with cowpea for improved soils and strong demand in the human and animal markets.
Contact Dr Frank Kayula, agronomist, director of the National Union for Small-Scale Farmers of Zambia