Submitted to: CD ROM
Publication Type: Other
Publication Acceptance Date: January 18, 2006
Publication Date: January 20, 2006
Citation: Nielsen, D.C. 2006. Central Great Plains Yield Calculator, CD version 2.2. CD ROM. Interpretive Summary: Central Great Plains producers need a simple tool to help them estimate crop yields. The most limiting factor to dryland crop yields in this region is water. The Central Great Plains Yield Calculator (distributed on CD) uses relationships (determined at Akron, CO) between available water and yield to estimate yields for 16 crops at 15 locations. Available water is based on available soil water at planting and fraction of expected growing season precipitation. The crops available on the Yield Calculator are corn, proso millet, winter wheat, chickpea, dry bean, lentil, pea, soybean, canola, crambe, sunflower, corn silage, forage kenaf, forage pea, forage triticale, and forage millet. The locations available on the Yield Calculator are Akron, Briggsdale, Fort Morgan, Julesburg, La Junta, Lamar, Limon, Stratton, and Wray, CO; Colby, Garden City, and Tribune, KS; and McCook, North Platte, and Sidney, NE. Pertinent fact sheets and journal articles describing yield response to available water are also included on the CD.
Technical Abstract: The Central Great Plains Yield Calculator is a simple Excel spreadsheet(distributed on CD) that calculates crop yield (for 16 crops: cereal grains, seed legumes, oilseeds, forages) based on user-selected values for available starting soil water at planting and expected growing season precipitation (average precipitation for 15 locations is included). Those two values are added together to form the estimate of growing season crop water use which is then used in a production function to calculate yield. The production functions were all determined at Akron, CO, with some data coming from the long-term dryland Alternative Crop Rotation study, and other data coming from gradient irrigation studies. These studies showed that both seed and forage yields were linearly related to seasonal crop water use. The calculator assumes that water is the controlling factor for yield, and that other factors (such as date of planting, fertility, weed control, insect control, timing of precipitation, and harvest efficiency) are optimal. The calculator also assumes that there are no significant weather influences such as hail, frosts, or excessive wind. The calculator should be a valuable decision support tool for producers wishing to diversify cropping systems. Pertinent fact sheets and journal articles describing yield response to available water are also included on the CD.