| Simulations were conducted to determine the effectiveness of a software package that fully automates center pivot irrigation systems on fields planted to corn, soybeans and potatoes for years 1986-2005. A total of seven sites from the Central and Northern Plains were chosen for analysis (Akron, CO, Ames, IA, Brookings, SD, Oakes, ND, Ord, NE, Rock Port, MO, and St. John, KS). System pumping capacities of 37.9, 50.5, and 63.1 liters/second were simulated at each site along with the soil available water holding capacities of 83, 125, and 167 mm/meter. The different combinations of pumping capacities and soil available water holding capacities resulted in a total of nine treatments at a given site per year. The software was able to schedule irrigations effectively using the ASCE Penman Monteith equation for estimating reference evapotranspiration (ET,) throughout the growing season for all crop types simulated.; For corn, the Akron, CO site had the smallest average ratio of rainfall to crop evapotranspiration (ETc) which resulted in the largest average number of days under minimum allowable soil water content per season (44 days, Treatment 7). (Abstract shortened by UMI.)... |
