Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 20, 2005
Publication Date: February 15, 2005
Citation: Nielsen, D.C., 2005. Crop residue and soil water. Proceedings of the 17th Annual Central Plains Irrigation Conference and Exposition, 16-17 Feb. Sterling, CO. p. 29-32. Interpretive Summary: Principles of limited tillage, crop residue management and their effects on precipitation storage efficiency are relevant to profitable crop production and good stewardship of the soil resource for both dryland and irrigated production systems. This paper reviews previous research showing influence of crop residue type, mass, and orientation on precipitation storage, and the effects of stored soil water on crop yield in the Great Plains.
Technical Abstract: Crop yield is greatly influenced by the amount of water that moves from the soil, through the plant, and out into the atmosphere. Winter wheat yield responds linearly to available soil water content at planting (bu/a = 5.56 + 5.34*inches). Therefore, storing precipitation in the soil during non-crop periods through good crop residue management is essential to profitable crop production in the central Great Plains. Precipitation is stored most efficiently during the cool months of fall, winter, and spring, averaging 65% storage efficiency in winter wheat stubble. Precipitation storage efficiency has increased from about 22% under plow systems to about 40% under no-till systems over the entire fallow period for wheat-fallow systems. Precipitation storage efficiency increases with mass of residue on the soil surface and with upright orientation of the residue. Upright residues are effective at reducing wind speed and trapping snow. Sunflower residue with a silhouette area index of 0.04 can increase stored soil water overwinter by 4 inches. Good residue management through no-till or reduced-till systems will result in increased soil water availability at planting. This additional available water will increase yield in both dryland and limited irrigation systems by reducing level of water stress a plant experiences as it enters the critical reproductive growth stage.