If ear size is reduced during this period, it cannot be corrected by relieving the moisture stress later in the season. Drought stress during corn silking and pollination can result in the greatest negative impact on yield potential. Plants under severe moisture stress during silking can lose more than 10 percent of their yield potential per day. Moisture or heat stress during this period can result in lack of synchronization between pollen shed and silk emergence. Unlike corn, soybeans are less sensitive during any particular phase of growth.
Soybeans continue to grow vegetatively during the flowering and podding stages.
Because soybean flowering and pollination occur over a longer period of time, soybeans are more likely than corn to escape serious damage from relatively short periods of moisture stress. Soybeans can branch, and thus compensate for delayed vegetative growth during a particularly dry period as long as adequate moisture is subsequently available. Soybeans also overproduce flowers and pods, which offers a degree of escape from short periods of stress. Soybeans that are stressed early in the season may still produce a good yield if subsequent water is available. For soybeans, the most critical period for adequate moisture is during pod fill.