Beans within pods should not show evidence of any green. If the beans have begun to dry, irrigation will not be needed because the beans no longer are removing much water from the soil profile. Soybean should be irrigated until sufficient moisture is available to allow full bean development and pod fill. At physiological maturity, pods are all yellow and over 65 percent of the lower pods have turned brown. Beans within pods should have little evidence of green color and should be shrinking.
Studies show that yellow pods sprinkled with brown are the best clue of physiological maturity.
The soybeans should be tolerant of a killing frost at this time also. This is when the backs of the heads turn from a lime green to yellow-green color and ray petals are completely dried. Potato will utilize soil moisture until harvest. Maturation stage begins with canopy senescence as older leaves gradually turn brown and die. Research has shown final irrigation can be used to reduce bruising during the harvesting process.