Managing harvest of 'Russell' and 'Tifton 44' bermudagrass receiving broiler litter for nutritive value and phosphorus removal

Bermudagrass [Cynodon dactylon (L.) Pers.] hay fields receiving broiler litter offer a means to both produce high quality forage and export excess manure nutrients, for example P. This 3-yr study determined the nutritive value, P removal, and soil P for `Russell' and 'Tifton 44' bermudagrass receiving 4 ton ac(-1) broiler litter and 98 lb ac(-1) N (as NH4NO3) annually and cut at 21-, 35-, and 49-d intervals with residual stubble heights of 1.2 and 3.5 inches. Forage cut every 49 d at 1.2-inch stubble height had the greatest dry matter (DM) yield and low nutritive value; weighted-sum crude protein (CP) ranged from 7.2 to 8.2% and weighted-sum in vitro true DM digestibility (IVTDMD) ranged from 56.8 to 62.0%, depending on year. With a 35-d interval, forage CP and IVTDMD amounts generally exceeded 9.6 and 62.0%, respectively. Forage IVTDMD was greater in Tifton 44 than Russell in 2006 and 2007, when values with a 35-d interval were approximately 3.0 and 0.3% greater, respectively. Cutting at a 1.2-inch height increased P removal by approximately 23% in Russell and 30% in Tifton 44 compared with a 3.5-inch height. Phosphorus removal was maximized with a 49-d interval and 1.2-inch height in 2005 (29.8 lb ac(-1)) and 2006 (19.3 lb ac(-1)) and with a 35-d interval and 1.2-inch height in 2007 (29.3 lb ac(-1)). Managing the balance between high DM and nutritive value in both cultivars can be achieved with a 35-d interval and 1.2-inch height. A prolonged harvest interval of 49 d is a valuable consideration for P removal via biomass.