Long-Term Broadcast and Banded Phosphorus Fertilization of Corn Produced Using Two Tillage Systems

Surface-broadcasting P is a management concern in no-till (NT) corn (Zea mays L.) production. Field research was established in 1983 and continued through 1993 to evaluate broadcast and banded P applications for corn produced utilizing NT and disk-till (DT) systems on a Loring silt loam (Oxyaquic Fragiudalfs). A wheat (Triticum aestivum L.) cover was established each fall. The tillage systems were main plots with a factorial arrangement of broadcast P rates, and the N + P band treatments were subplots. Annual broadcast P rates were 0, 20, 39, and 59 kg ha−1 A 22–20–0 kg ha−1 N + P band was applied after planting. All plots received a total of 168 kg N ha−1 each year. Disk-till yields were higher than NT yields for 5 of the 11 yr and were increased by P rates up to 39 kg ha−1. No-till yields were increased with P rates up to 20 kg ha−1. Yield response to banding N + P was inconsistent with year, tillage, and P rates. Three banded N + P plus broadcast P combinations equal to a broadcast P rate were applied each of the 11 yr. Yields for 5 of the 33 comparisons were increased by the banded plus broadcast P combination while three yields were reduced relative to broadcasting equal P rates. Yields for the other 25 comparisons were similar. Extractable P (EP) was increased with increased broadcast P rates, but the yield response was generally restricted to low EP situations.