Cropping Under Drought Conditions.

Evapotranspiration (ET) or crop water use is the combined process of both evaporation from soil and plant surfaces and transpiration from plant canopies through the stomates to the atmosphere. In the ET process, water is transferred from the soil and plant surfaces into the atmosphere in the form of water vapor. With bare soil, evaporation can be more than one-third of the crop water use in irrigated corn. This can be reduced to 15% with good crop residue cover. This results in reducing the ET in corn by up to 13 centimeters. If you have bare soil or soil with little crop residue, tillage or cultivation was probably performed. Each of these operations can reduce soil water by approximately 1 to 2 centimeters. Besides reducing the E in ET, one needs to be able to store precipitation in the soil when it occurs. In conventional farming with controlled traffic, the water intake rates for silty clay loam soil range from 0.5 centimeters per hour in the traffic areas to 1.0 centimeters per hour in the non-traffic areas. In no-till with controlled traffic, the water intake rate on a silty clay loam soil in the traffic area is 1.25 centimeters per hour while in the non-traffic area, it is over 10.0 centimeters per hour. These factors plus crop residue management, cropping practices including skip-rows, crop selection and pest management all assist with cropping under drought conditions.