Many areas of Wisconsin have not had rain for three to four weeks. Corn growing on lighter soils is starting to show signs of stress early in the morning. Many are concerned about how this drought might affect corn yields. To begin talking about water influences on corn growth and development and yield we must begin with the concept of evapotranspiration. Evapotranspiration is both the water lost from the soil surface through evaporation and the water used by a plant during transpiration .
Soil evaporation is the major loss of water from the soil during early stages of growth.
As corn leaf area increases, transpiration gradually becomes the major pathway through which water moves from the soil through the plant to the atmosphere. Yield is reduced when evapotranspiration demand exceeds water supply from the soil at any time during the corn life cycle. Nutrient availability, uptake, and transport are impaired without sufficient water. Plants weakened by stress are also more susceptible to disease and insect damage. Corn responds to water stress by leaf rolling.