Remaining usable moisture in the root zone. Probability of significant amounts of rainfall before crop maturity. Obviously, rainfall is difficult to predict. Consequently, we assume that no rainfall will occur. The procedures presented are designed for maximum crop yield.
Physiological maturity is defined as the time when kernels or seeds have stopped filling.
For corn and grain sorghum, black layer formation at the tip of the kernel is a good indicator of maturity. For soybeans, beginning maturity is when one normal pod on the main stem has reached its mature pod color. Further information on soybean growth stages is given in Table I . Table I. Reproductive stages of soybean plant development. Stage Description Beginning Flower R1 One open flower at any node on the main stem.