ASA Southern Branch 2008 Annual Meeting
February 3-5, 2008
Dallas, TX
Sunday, February 3, 2008
Effects of Avail on Phosphorus Utilization of 'Tifton' 85 Bermudagrass.
Brandon Stewart, University of Arkansas, 362 Hwy 174 North, Hope, AR 71801, Paul A. Beck, University of Arkansas Southwest Research & Extension Center, 362 HWY 174 N, Hope, AR 71801, Larry Murphy, Fluid Fertilizer Foundation, Fluid Fertilizer Foundation, 2805 Claflin Rd. Ste. 200, Manhattan, KS 66502, and Melissa M. Beck, Cooperative Extension Service, University of Arkansas, 532 West 1st. Street, Prescott, AR 71857.
Abstract
AVAIL (Specialty Fertilizer Products,Manhattan , Kansas ) is a polymer that is added to diammonium phosphate (DAP) that inhibits phosphate fertilizer from becoming fixed in the soil. This study was conducted to determine the effects of phosphorus source (DAP vs. AVAIL) on dry matter yields of ‘Tifton 85’ bermudagrass over 4 harvests. Diammonium phosphate or AVAIL (56 kg/P2O5/ha) was applied to test plots (1.5m x 6m) at the initiation of the study (May 18) plus urea or urea + NSN to bring N rates to 56 kg/N/ha. Additional plots did not receive fertilizer or received urea or urea + NSN (56 kg/N/ha) only to distinguish N and P effects. A phosphorus source by harvest interaction (P<0.0001) for DM yield required that data be sorted by harvest and analyzed as a split-plot. At the first harvest, phosphorus treatments and companion N treatments produced significantly more forage than non-fertilized control (P <0.0001). However, there were no differences seen (P = 0.4812) between P and companion N treatments (average 1,839 kg/ha). At the second harvest, DAP produced significantly more (P = 0.0303) yield than AVAIL (4,094 vs. 3,693 kg/ha). Urea + DAP produced more forage (P<0.0001) than urea + AVAIL and urea alone (4,402 vs. 3,678, and 3,644 kg/ha, respectively). Urea + NSN + DAP and Urea + NSN + AVAIL produced more forage (P<0.0001) than urea + NSN alone (3,984, 3,709, vs. 3,422 kg/ha, respectively). At the time of the third harvest, Urea + NSN + AVAIL, urea + AVIAL, and urea + NSN + DAP produced more forage (P = 0.0222) than urea, urea + NSN, and urea + DAP (1,921, 1,874, and 1,869 vs. 1,721, 1,599, and 1,567 kg/ha, respectively). At the final harvest, all P treatments and companion N treatments produced significantly more forage than the control (P <0.0001). However, there were no differences seen (P = 0.9615) between P and companion N treatments (average 1,438 kg/ha).
AVAIL (Specialty Fertilizer Products,