Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 14, 2000
Publication Date: N/A
Technical Abstract: Availability of affordable global positioning systems and yield monitors for many crops has stimulated interest in site-specific management of crop inputs such as irrigation and fertilizers. Farmers can now directly measure the effects of varying inputs on crop yield. Two commercial center pivot irrigation systems were modified (one in 1995, the second in 1998) to provide site-specific water and fertilizer applications to management zone as small as 100m**2. These modified systems were used in 1999 to determine the effects of a range of water and N-fertilizer rates on corn grain yield. One system was sited on a fairly uniform soil while the other was sited on a site with 12 soil map units. Corn grain yield increased with increased irrigation amount at both sites. Yield increased with N-fertilizer rate between the 50% and 75% rates, but not for higher rates at this site or for the two N-fertilizer rates at the variable-soil site. Yield responses to irrigation varied among the various soil map units, with some soils responding more than others. Once crop yield effects of variable inputs, soils, and economic factors are known, site-specific water and N-fertilizer applications can be developed for individual management zones.