Effect of Planting Date on Soybean Growth, Yield, and Grain Quality: Review

Abstract

Delayed planting date and unfavorable environmental conditions have a negative effect on soybean [Glycine max (L.) Merr.] growth, development, and yield. Changes in photoperiod, temperature, and precipitation with delayed planting affect the duration of vegetative and reproductive stages, number of branches and pods, plant height, leaf area index (LAI), and normalized difference vegetation index (NDVI), and hence the grain yield. Delayed planting can also affect the soybean seed quality by changing the oil and protein content. Environmental factors like extremely high temperature and drought stress, which are often associated with delayed planting, have also a negative effect on plant development and yield. Compared to optimum air temperature, reduction in photosynthetic rate during heat stress decreases seed set and size, and seed yield. Drought stress during reproductive stages reduces carbon dioxide exchange rate (CER), photosynthesis, sugar production, and flow of metabolites to the expanding cells, which increases flower and pod abortion and decreases vegetative growth, duration of the seed filling stage, seed number, and seed size. Generally, the combined effect of photoperiod, temperature, and precipitation with delayed planting most likely contributes to decreased duration of vegetative and reproductive growth stages, reduced photosynthesis and plant growth, and therefore significant reduction in grain yield of soybean.