The impact of legumes relay-intercropped into maize at Domboshava, Zimbabwe
1998
Jeranyama, P. | Hesterman, O.B. | Waddington, S.R.
The impact of relay-intercropping a food legume (cowpea, Vigna unguiculata L.) and a tropical forage legume (sunnhemp, Crotalaria juncea L.) into maize was evaluated at Domboshava in Zimbabwe. For both legumes the accumulation of dry matter was greatest at 75 days after relay-intercropping. Herbage biomass (averaged over two years) was 2.3 Mg ha-1 for cowpea and 3.1 Mg ha-1 for sunnhemp. Highest total nitrogen (N) accumulation in the legume biomass was 111 kg N ha-1 for sunnhemp and 59 kg N ha-1 for cowpea. Relay-intercropped maize fertilized with 60 kg N ha-1 had grain yields equal to or better than those of a sole maize crop at the same fertilizer rate. However at the other N rates, maize yields were reduced indicating competition between the maize and the legume. In the subsequent year, maize following maize relay-intercropped with the legume produced 20% more grain yield than the sole maize control. The grain N content of a subsequent maize crop was improved by 82% relative to the sole maize control. The legume replaced up to 36 kg N ha-1 of the N requirements in the subsequent maize crop.
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