Using Extension Phosphorus Uptake Research to Improve Idaho's Nutrient Management Planning Program

Irrigated silage corn is the main crop used for P removal in southern Idaho; however, little is known about the actual amounts of P removed under southern Idaho growing conditions. The study surveyed P removal by irrigated silage corn in primarily manured southern Idaho fields and wide-ranging soil test P. Whole plant corn tissue P concentrations ranged from 0.116 to 0.307% total P and averaged 0.208%—lower than Natural Resources Conservation Service (NRCS) estimates used prior to 2007 (0.26%P) but higher than estimates used since 2007 (0.185%). The study was used to update the OnePlan.org© Nutrient Management planning online program.