Yield is reduced most when stress starts during soft dough or during or following heading. Stress during maturing results in about a 10 percent lower yield. Moderate stress during the early vegetative period has essentially no effect on yield. Drought stress on winter wheat production during early spring regrowth results in heading about seven to 10 days prematurely, a shortened growth period and thus reduced yield. Early stress results in development of more heads than usual but many fail to produce grain.
Winter wheat is most sensitive to drought during shooting and booting.
It is essential to avoid even slight water stress at jointing. Withholding water to increase tillering may lead to premature heading and grain maturity. Potato production is directly related to crop water use between emergence and defoliation. Potatoes are not susceptible to severe yield reductions from short periods of moderate stress during any single period of production. Alfalfa forage yield is directly related to available water and actual plant water use.