Harvest Management Effects on Nutrient Uptake and Forage Nutritive Value of 'Tifton 44' Bermudagrass Receiving Broiler Litter.

Producing bermudagrass hay from fields receiving broiler litter provides both high quality forage for ruminant livestock and a means of exporting manure nutrients to reduce potential surface and ground water impairment. Objectives were to determine (1) the effects of harvest interval (aka, forage maturity) and cutting height on dry matter (DM) yield and nutrient utilization and (2) the best compromise between P removal and nutritive value (CP, IVTDMD, etc..) in the different harvest management systems. Summer growth of ‘Tifton 44’ bermudagrass was harvested at intervals of 21, 35, and 49 days and stubble heights of 3 and 9 cm in 2005-2007. Studies were conducted at a private farm near Noxapater, MS and at the Mississippi State University H. H. Leveck Animal Research Center (South Farm). Fertilization consisted of 4.5 Mg ha^-1 broiler litter in March and May (~243 kg mineralizable N ha^-1) and 67 kg N ha^-1 (34-0-0) in late May each year. Cumulative DM and N, P, and K uptake at South Farm increased as maturity increased and as cutting height decreased; whereas, these trends at Noxapater were observed for DM and P uptake only. A 35-day harvest interval appeared to optimize N and K uptake. Seasonal trends in P uptake closely followed those observed for DM yield and cumulative yield of both parameters increased approximately 30% by cutting at 3-cm height, as compared with 9-cm height. Results indicated Tifton 44 bermudagrass receiving broiler litter should be harvested every 35 or 49 days and at 3-cm stubble height to provide the best compromise between attaining DM yield, nutrient utilization, and nutritive value to ruminant livestock.