Crop arrangement patterns in intercrop systems affect resource efficiency and yield of the companion crops. The degree of interaction within and between species in intercrop systems depends on crop life cycle and morphology. Experiments were carried out to determine the effect of row-intercrop arrangement on four phenologically close but morphologically contrasting varieties of green gram (Vigna radiata L.) intercropped with sorghum (Sorghum bicolor L.) in southeastern Kenya. Split-plot design was used, with crop arrangement (sole crop, single and double-row intercrop) as main plots and green gram variety in the subplots. Four green gram varieties of N26, KS20, Karembo, and Biashara were intercropped with sorghum variety Seredo. Sole crops of each green gram variety and sorghum were added as control. Variety N26 had a large canopy, quicker growth rate (7.2 g m-2 day-1), and out-yielded the other varieties by 1.09 t ha-1. Sole crops of green gram (irrespective of variety) and sorghum recorded higher growth rates and yield compared with intercrop systems. However, crops grown in double row, out-yielded those in single row arrangement. Green gram yield was a function of the number of branches and seed number m-2 while sorghum yield was directly proportional to tiller number and grain number m-2. Results imply that the yield of green gram intercropped with sorghum could be improved through the use of varieties with rapid growth rates and wider intercrop strips to maximize intraspecific and interspecific interactions.
Yumbya et al. (Sun,) studied this question.