Stress during the early vegetative stage is not nearly as serious as stress during flowering, pollination and early seed filling. Stress during any part of the cropping season limits grain corn production. To maximize water use efficiency in grain corn, it is best to limit irrigations during the vegetative stage. The period from emergence to 12-leaf was lease sensitive to stress. Barley responds to drought stress much like corn and other cereal crops.
Yield is likely to be reduced very little when drought stress occurs during the vegetative period.
However, a major disadvantage of early drought stress is the tendency for plants to tiller more than usual. Although the increased tillering is desirable, often the tillers never produce grain-yielding heads. Barley is most sensitive to stress during jointing, booting and heading. Considering drought stress before, during and after heading, yield is reduced the most by drought before heading. Flowering and pollination appear to be the most sensitive periods.