In the humid and sub-humid East African highlands, soil fertility situations are more serious due to continuous cropping with little or no external inputs and removal of crop residues. As a result, sustainability of soil productivity has been under threat due to continuous soil fertility depletion. The problem can be alleviated by inclusion of legumes in crop rotations and retention of crop residues. To properly popularize the merits of legumes for soil fertility improvement in maize systems, a network of research trials on potential legumes had been conducted in Ethiopia, Tanzania and Uganda. Research activities of the network during 1998-2001 included screening of potential legume species, and evaluation legume/maize crop management systems undertaken on-station and on-farm. Based legume species screening trials, Mucuna, Canavalia, Crotolaria and Dolicos lablab were used in maize/legume systems studies. Minimum dry biomass to be incorporated for better productivity of maize was determined to be 5 t ha-l. A significant increase in maize yield was obtained where legumes were preceded as sole crops in rotations; increases were less consistent in simultaneous and relay intercropping systems. The yield advantages of maize/legume systems over the continuous maize without N fertilizer were from 0 to 135%. At Jimma and Tanga, higher productivity was obtained from maize following sole legumes. The fertilizer value of total legume N was estimated to exceed 50 and 69 kg N ha-1 that can replace the current need for mineral N fertilizer at Tanga and Jimma, respectively. In Hai District, Tanzania, economic and gender analysis found good possibilities to adopt these legumes in intercropping systems, particularly in the case of lablab for which there is a commercial market available for its grain.

Global Maize Program

Text in English

0409|AGRIS 0401|AL-Maize Program

CFDE01

CIMMYT Staff Publications Collection