1. Nitrogen Application, Biological N Fixation, and N Uptake

Previous collaborative research in the Midwest has shown that there is likely little to no need of N for soybean, except under certain conditions (such as when low soil moisture limits N fixation, or when low initial soil nitrate-N limits overall N availability). However, none of the site-years used in this synthesis analysis were on sandy soils. Because sandy soils supply little nitrate-N, the potential impact of N on crop yield is greater in sandy environments than on silt loam soils. However,... A.M. Walters, M.D. Ruark, J.M. Gaska, C. Zegler, S.P. Conley