Effects of Canopy Arrangements on Light Interception and Yield of Soybeans1

Abstract

Leaf and branch arrangement simulating various degrees of lodging produced significant changes in light interception and yield of soybeans. For the 3 years of the experiment, maximum light penetration occurred with a moderate amount of plant spread simulating a small but definite amount of lodging. Generally, the largest part of the light interception occurred in the outer 15 to 30 cm of the plant canopy. Greater light penetration, resulting in a greater amount of the plant canopy having light intensity above 150 ft‐c, generally resulted in greater yields. A photographic technique involving the evaluation of leaf area in the sun was closely related to yield but found to be too time consuming for practical use. Greater oil content was generally associated with greater light penetration. The effect of shading of adjacent rows was greater in 1‐m row spacing than on 1.5‐m row spacing.