Role of Crop Residues—Improving Water Conservation and Use

This chapter presents an overview of the early results, discuss results from residue management systems, and discuss research needs and goals for further improving water conservation and use under surface residue conditions. Surface residues with minimum- and no-tillage treatments reduced evaporation as compared with conventional tillage. Stubble mulch tillage greatly reduced runoff and erosion and quickly became a recommended soil conservation practice in the southeast USA. Improved wind erosion control was a definite advantage of early no-tillage, but effects on water conservation and crop yields were variable because herbicides sometimes did not control weeds during the interval between crops. Economic factors contributing to interest in conservation tillage include: ability to use erosive land for more intensive crop production. The greater difficulty results from such factors as higher potential evaporation, mainly late spring to early fall precipitation, a long growing season for weeds, and low levels of crop residues associated with generally low crop yields.