Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 13, 2008
Publication Date: October 5, 2008
Citation: Schwartz, R.C., Dao, T.H., Bell, J.M. 2008. Phosphorus dynamics in amended soils during a growing season: I. Availability and plant uptake [abstract].2008 Joint Meeting of American Society of Agronomy, Soil Science Society of America, and Crop Science Society of America, October 5-9, 2008, Houston, Texas. Paper No. 693-6. 2008 CD ROM. Technical Abstract: Recent studies indicate that soil extractable P and P in runoff are greatest immediately after fertilizer and manure applications. Our objective was to evaluate changes in Mehlich 3– and water– extractable P in soils amended with cattle (Bos taurus) manure and monoammonium phosphate (MAP) throughout two growing seasons. Cattle manure and MAP were applied at a rate of 184 and 300 kg P ha**-1, respectively, on a Pullman clay loam (Fine, mixed, superactive, thermic Torrertic Paleustoll). Unfertilized checks were included for P extractability comparisons. Grain sorghum (Sorghum bicolor (L.) Moench) was planted after fertilizer applications and received supplemental irrigation. Soil samples (0-150 mm) were collected prior to fertilizer applications and periodically throughout the growing season. Changes in Mehlich 3– and water– extractable P with time exhibited a rapid initial increase after fertilizer applications followed by seasonal fluctuations and a decline 15 weeks after planting.