Effect of plant population on growth and yield of soya bean(Glycine max)

Abstract

SummaryIn soya beans (var. 3H55F4/149/1) grown in Tanzania, the total dry matter per plant, pod weight/stem weight, shelling percentage, number of nodes per plant, number of pods per plant, percentage number of nodes with pods, number of filled pods per plant, number of branches per plant, and grain weight from side branches decreased with increase in plant density from 74 to 111, 222, and 444 thousand plants per hectare. Grain yield per hectare decreased by 38, 51, and 72% respectively with the increases in plant population, but yield of total dry matter per hectare showed a significant increase with density. Crop growth rate increased with increasing leaf area, which in turn increased with increasing plant density. Relative growth rate, however, decreased with rising population. Over the range of the densities studied grain yield was positively related to number of side branches but negatively related to dry-matter production, leaf area duration and percentage of light intercepted. The proportion of dry matter accumulated in the pods and side branches decreased with increase in population, whereas the proportion accumulated in the main stem increased. Light seems to be the major factor controlling grain yield in this variety of soya bean, low light intensity under the plant leading to a reduction in the number of side branches, number of pods per plant and number of nodes with pods.