Studies in Mixed Cropping. II. Population Pressures in Maize–Bean Mixtures

Abstract

SUMMARYAn experiment at the Kabete Field Station of the University of Nairobi compared maize–bean mixtures with pure stands of the two crops at three plant densities. Although the mixtures gave an apparent yield advantage over pure stands, this could be explained solely by the increased population pressure in the mixtures. The implication of this finding for other published work with cereal–legume mixtures is discussed, and a distinction is drawn between those sites in East Africa where a conclusive yield advantage from mixed cropping has been found and those where any apparent advantage might be explained by the higher population pressure.

Effect of Plant Density and intercropping Pattern on yield and Competitive Relationships of Maize and Cowpea

“…The increase in maize grain yield that was recorded per unit area is a good indicator that the cowpea is not competitor for the maize and inter specific competition between both species is much lower than the intra specific competition. Similar results were recorded by Fisher (1977) and Shivay and Sing (2000).…”

“…Intercropping cereals with legumes often increase the total yield due to better utilization of environmental resources. In this connection, Fisher (1977) indicated that intercropping maize with some legumes gave yield advantage over pure stand. Yield advantage was attributed to the increase in population of these mixtures.…”

Growth and Yields of Intercropped Sorghum and Sunflower (Helianthus annuus L.) in Semi‐arid Nigeria

“…This difference in the time of reproductive development is advantageous because the two crops did not come to the stage of maximum demand for nutrient and moisture, aerial space and light at the same time. Where this occurred reduction in yield has been reported (ENYI 1973, FISHER 1977. Nevertheless, intercrop competition with sunflower was injurious to sorghum especially when intercropped in alternate hills in the same row.…”

Assessment of the Agronomic Performance of Two Varieties of Soybean as Influence by Time of Introduction of Maize and Cropping Pattern

“…Generally, CR values decreased with delayed maize introduction, The much reduction in maize grain yield in intercropped could be as a result of the semi additive population used, which translates to half maize population in cereal/legume intercropping in order to reduce excessive shading (Fisher, 1977 …”