Evaluation of five bermudagrass cultivars fertigated with swine lagoon effluent

Bermudagrass [Cynodon dactylon (L.) Pers.] hay is an important output from land receiving swine (Sus scrofa) effluent application (also known as spray fields); however, there is limited information about cultivar differences in the upper Southeast United States. Herbage accumulation, nutritive value, tissue nitrate concentration, and stem maggot damage were evaluated for five bermudagrass cultivars ('Coastal', 'Midland 99', 'Ozark', 'Tifton 44', and 'Tifton 85') fertigated with swine effluent throughout three growing seasons (2016, 2017, and 2018). All cultivars achieved canopy height >= 35 cm by July and cover of 100% by August of year of planting. Based on 3-yr averages, Tifton 85 (9.3 Mg ha(-1)) had greater herbage accumulation than cultivars Coastal, Ozark, and Tifton 44 (approximate to 7.9 Mg ha(-1)), and Midland 99 was intermediate (8.5 Mg ha(-1)). Bermudagrass stem maggot (Atherigona reversura) damage was consistently lower for Tifton 85 and resulted in larger differences in herbage accumulation in 2017 (11.2 vs. 8.4 Mg ha(-1) for Tifton 85 and the other cultivars, respectively). There were moderate differences in crude protein concentration (ranged from 179 to 212 g kg(-1)) and no difference in total digestible nutrients (622 g kg(-1)). Tissue nitrate concentrations ranged from 3,433 to 16,168 mg NO3- kg(-1). Differences in productivity and nutritive value were moderate among cultivars; however, in areas with potentially high bermudagrass stem maggot damage, greater utilization of Tifton 85, if adapted, is warranted. Hay production from spray fields results in high yields and high nutritive value forage. Frequent nitrate testing, if possible by harvested hay lot, is advised.