CIG Demonstration of Cycling and Export of Manure Nutrients through Sod.

An NRCS CIG project demonstrated manure and wastewater cycling through tufgrass sod on three Texas watersheds. Composted dairy manure (CDM) was topdressed at a total P rate of 124 kg ha^-1 on TifSport bermudagrass on the Leon River Watershed. On the Brazos River Watershed, topdressed poultry litter (PL) supplied 82 kg total P ha^-1 for regrowth of Tifway bermudagrass. A joint venture in Zoysiagrass production between Stoney Point Feedyard and TriTex Grass on the Trinity River Watershed provided the third demonstration. Topdressing of CDM on TifSport sod increased soil organic C concentration 44% and gravimetric water content 25% compared to controls. In addition, total soil N concentration was 49% greater and total P concentration was 64% greater with than without CDM. Similarly, CDM increased TifSport tissue concentrations 12% for total N and 120% for total P. At TifSport harvest, 95% of total P and 66% of the total N top-dressed in CDM were exported with sod. Topdressing of PL on Tifway sod fields within the Brazos River Watershed increased both soil organic C concentration and gravimetric soil water content 31% compared to the control. Turf coverage rate was greater, total N concentration was 32% greater in soil and 34% greater in turfgrass, and total P concentration was 53% greater in soil and 130% greater in turfgrass for Tifway topdressed with PL than the control. Increased soil P concentration after topdressing of PL increased dissolved P (DP) concentrations in runoff  (3.6 mg L^-1) compared to the Tifway control. On the Trinity River Watershed, DP concentrations in runoff of simulated rain from Zoysiagrass turf were 3.5 mg L^-1 after manure incorporation and wastewater application. Cycling of CDM, PL, and feedyard manure and wastewater benefits sod production, but rate and method of application and runoff need to be managed to protect water quality.