208-5
Water Soluble P From Poultry Litter and Flue Gas Desulfurization Gypsum Amended Hay Field in Watkinsville GA.

Tuesday, November 5, 2013: 11:05 AM
Marriott Tampa Waterside, Room 11, Third Level

Dinku Endale, Southeast Watershed Research Laboratory, USDA-ARS, Tifton, GA, Harry H. Schomberg, Sustainable Agricultural Systems Laboratory, USDA-ARS, Beltsville, MD, Dwight Fisher, J. Phil Campbell, Sr., Natural Resource Conservation Center, USDA ARS, Watkinsville, GA, Dorcas H. Franklin, Crop and Soil Sciences Dept., UGA, Athens, GA and Michael B. Jenkins, Water Quality and Ecology Research Unit, NSL, USDA-ARS, Oxford, MS
The research focused on evaluating if flue gas desulfurization (FGD) gypsum reduces P losses from hayed or pasture fields receiving poultry litter (PL).  Plots were established in fall of 2008 on a field that had been hayed for at least 20 years. Treatments included four rates of FGD gypsum  (0, 2.2, 4.5, and 9.0 Mg ha-1) each with PL at 13.5 Mg ha-1, and two control treatments,  one with no FGD gypsum or PL (0-0), and the other with FGD gypsum at the highest rate without PL ( 0-9.0). The six treatments were replicated three times. The 4 by 6 m plots received treatments in April to early May in 2009, 20010 and 2011. Soil samples were collected from 0-2.5, 2.5-5.0, 5.0-7.5, 7.5-15.0 cm depth just before rainfall simulation runs beginning 6/8/2009 and 5/9/2011 and analyzed for water soluble P (WSP). The surface 0- to 2.5-cm soil depth contained a large part of the WSP measured in sections down to 15 cm (Least square means 4 to 79 mg kg-1). Treatment effects occurred in the surface 5-cm depth only. In the 0- to 2.5-cm depth, PL doubled the WSP in both years compared with the (0-0) treatment (p ≤ 0.002). Addition of gypsum to the PL resulted in a significant linear decrease of WSP with increasing gypsum rate (p = 0.003) in 2009 but not in 2011.  Gypsum at the highest rate with litter reduced WSP by ~26% compared with the treatment with litter only. Addition of gypsum to the zero amendment control reduced WSP by 38% (p = 0.05). The only treatment effect in the 2.5- to 5.0-cm depth was a 1.7- to 2.4-fold increase in WSP due to litter or litter with gypsum in 2011 compared with the (0-0) control (0.003 < p ≤ 0.084).
See more from this Division: ASA Section: Environmental Quality
See more from this Session: By-Product Gypsum: Beneficial Uses in Agriculture: I

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