Effect of Phosphorus Placement Methods and Rates on Sugarbeet Production under Strip Tillage in Southern Idaho

Abstract

The use of strip tillage in the sugarbeet production systems of the Pacific Northwest is increasing, and data is needed about options for P placement and application rates for those options. The effects of P application methods (surface and subsurface band) and application rates (0–205 lb/acre P2O5) were evaluated in 2009 and 2010 on sugarbeet grown under strip tillage at the USDA‐ARS Northwest Irrigation and Soils Research Laboratory, in Kimberly, ID. The soil at the study sites was a Portneuf silt loam (coarse‐silty mixed superactive, mesic Durixerollic Xeric Haplocalcids) that had low bicarbonate‐extractable P concentrations of 3.7 ppm in 2009 and 6.0 ppm in 2010. In general, yields did not differ between the application methods for P fertilizer application; however, yields increased as the P rate increased and were not maximum even at the highest application rate in this study (>205 lb/acre P2O5). Across all treatments and years, the harvested roots removed an average equivalent of 14.3% of the applied fertilizer P, and the entire plant extracted an average equivalent of 22.8% of the applied fertilizer P. Regardless of the application methods used in this study, the results do not provide evidence that the current P fertilizer recommendations from the University of Idaho and the Amalgamated Sugar Company (TASCO) should be changed for strip tillage.