Economics of Maize and Bean Production: Why Farmers need to Shift to
Conservation Agriculture for Sustainable Production
Maize and dry bean are the most important food crops that feed over 85% of Kenyan households.
However, the productivity of these crops is low due to the high costs of land preparation and weed
control, soil infertility and limited soil moisture under the current conventional tillage system of
production. A study was carried in Embu County and Kirinyaga County to determine the economic
returns of a maize-bean rotation system under different tillage systems and fertilizer regimes. Maize
was produced during the long rains under no-till with crop residue retention (NT+CR) and
conventional tillage with no crop residue retention (CT-CR) and inorganic fertilizer regimes (NK,
NP, PK, NPK, and NPK+CaMgZnBS). Dry bean was planted in the short rains in the same plots
where maize under different nutrient management regimes and tillage systems had been grown and
harvested. The trial was laid out in a split-plot design with the tillage method as the main plot and
fertilizer as sub-plot. Economic performance was assessed using partial budget analysis based on
labor data and prices of all inputs used during the production period. Grain yields were reduced by
10% to reflect farmers’ yield levels. Maize and dry bean grains were sold at the prevailing farm gate
prices. Results showed that maize-bean rotation was KE 22,718 cheaper under no-till with crop
residue retention (NT+CR) than under conventional tillage with no crop residue retention (CT-CR).
On average, NT+CR recorded KE 29,569 higher net benefit than CT-CR. The NT+CR tillage
recorded a benefit to cost ratio of 3.7 compared to 2.7 recorded under CT-CR tillage system. The
NT+CR with NK combined was the most profitable treatment with a benefit to cost ratio of 4.92 for
maize and 4.33 for maize-bean rotation system. Based on this research, combination of no-till with
crop residue retention has the potential to improve economic status and alleviate poverty among resource-constrained farmers.