Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/24/2005
Publication Date: 4/26/2005
Citation: Read, J.J., Brink, G.E., Kingery, W.L., Oldham, J.L. 2005. Bergmudagrass production and nutrient uptake when substituting broiler litter nitrogen with mineral nitrogen [abstract]. Proceedings Mississippi Water Resources Conference and 2nd Symposium on Safe Management and Utilization of Animal Waste. p. 43. Interpretive Summary: Broiler litter (a mixture of chicken manure, wasted feed, and bedding materials) is commonly used as fertilizer for growing bermudagrass hay. Efficient management of litter nutrients minimizes any loss of nutrients to the environment, particularly nitrogen (N) and phosphorus (P), which may decrease water quality. Studies at two farms in Mississippi determined if substituting the organic (N) in litter with inorganic fertilizer (ammonium nitrate, 34% N) is effective in increasing bermudagrass growth and uptake of N and P. Treatments included five rates of litter that were combined with five rates of inorganic fertilizer so that each treatment provided about 240 pounds N/acre/year, which is the annual N requirement for bermudagrass hay. At a farm with long history of litter applications and relatively high soil fertility, substituting inorganic N for litter N did not significantly increase yields or nutrient uptake. At a farm with no history of litter application, bermudagrass yield and uptake of N and P were generally greatest when fertilized with 4 tons of litter and 120 pounds of inorganic N. A proposed best practice for efficient management of soil nutrients is to provide half the N requirement of bermudagrass with litter (about 2 tons/acre) in spring and the remainder with inorganic N fertilizer. Results provide information to farmers on how to use broiler litter safely and efficiently in forage crop production.
Technical Abstract: Achieving adequate hay production from bermudagrass [Cynodon dactylon (L.) Pers.] with P as the basis for applying broiler litter will require supplementation with mineral N. Field studies were conducted to determine if substituting mineral N (ammonium nitrate, 34-0-0) for broiler litter N increases P uptake (=biomass yield x tissue concentration) from soils with low and high soil test P (STP). Plots (4 x 6 m) of ‘Coastal’ bermudagrass were established at Mize, MS in a pasture with 30+ year history of litter application and STP of 409 kg/ha, and at Newton, MS in a pasture with STP of 52 kg/ha. Litter rates of 0, 4.5, 8.9, 13.4, and 17.9 Mg/ha were made in increments of 4.5 Mg/ha beginning in April, and were supplemented with 67 kg N/ha following each harvest to achieve 269, 202, 134, 67, and 0 kg N/ha, respectively. Treatments, including an unfertilized check, were repeated on the same plots in 1999, 2000, and 2001. Significant treatment difference in forage dry matter (DM) and P uptake were detected at Newton (P<0.01), but not at Mize (P>0.50). At Mize, DM and forage P concentration >90% of maximum relative yield were obtained from 4.5 Mg + 202 kg N treatment. At Newton, the 8.9 Mg ha-1 + 134 kg N ha-1 treatment appeared to maximize forage DM and P uptake. Results indicate broiler litter rates should not exceed 8.9 Mg ha-1 yr-1 and be supplemented with mineral N to meet bermudagrass N requirement. This practice appears to have greatest benefit when rainfall and other conditions are favorable for growth.