RT Journal Article SR Electronic T1 Optimum placement of phosphorus for corn/soybean rotations in a strip-tillage system JF Journal of Soil and Water Conservation FD Soil and Water Conservation Society SP 152A OP 153A DO 10.2489/jswc.63.5.152A VO 63 IS 5 A1 Randall, Gyles A1 Vetsch, Jeffrey YR 2008 UL http://www.jswconline.org/content/63/5/152A.abstract AB