330-14 Field-Scale Measurement of Ammonia Volatilization From Turfgrass Fertilizers.



Wednesday, October 19, 2011
Henry Gonzalez Convention Center, Hall C, Street Level

Elizabeth A. Guertal, Agronomy and Soils, Auburn University, Auburn, AL
Ammonia volatilization from fertilized turfgrass can be an issue of concern, especially if irrigation is not available, and if urea-based N sources are used. The objective of this work was to quantify ammonia loss from fertilized turfgrass as affected by N source. The 10 week experiment took place in 2009 and 2010 on a mixed sward of bermudagrass (Cynodon dactylon Pers.) and bahiagrass (Paspalum notatum) maintained at a mowing height of 6.4 cm. There were four fertilizer treatments for the experiments, each replicated three times. An unfertilized background control plot was also included. Treatments were the N fertilizer sources urea (46-0-0), polymer coated urea (42-0-0), UMaxx (47-0-0), and XCU (43-0-0). Fertilizers were applied at 7.3 g m-2 in July of 2009 and 2010, with no irrigation. Ammonia was captured from 45-m diameter circular plots using a passive micrometeorological system, which uses a three meter high rotating mast was placed in the center of the plot. Five NH3 collection tubes were inserted perpendicular to the mast at 5 heights along the mast: 40, 70, 150, 220, and 300 cm above the soil surface. Tubes were collected once a week for 10 weeks, and ammonium extracted from each tube, and analyzed colorimetrically. Without irrigation to incorporate the urea, NH3 loss from that source was substantial, and averaged 25% of N applied. Ammonia loss from the other sources typically averaged around 10% of N applied. Regardless of N source, greatest NH3 volatilization occurred in the first week after application.
See more from this Division: C05 Turfgrass Science
See more from this Session: Turfgrass Ecology, Pest Management, and the Environment