Search

Nitrogen fertilizer use is generally restricted in bermudagrass [Cynodon dactylon (L.) Pers.]-white clover (Trifolium repens L.) forage systems because it stimulates grass growth and increases competition with the clover, compromising forage nutritive value and prospective forage accumulation. Enhanced efficiency fertilizer nitrogen (N) products hold potential to improve white clover persistence in bermudagrass- clover pastures while providing supplemental N required by the grass. This study evaluated the effect of different enhanced efficiency N formulations (Environmentally Smart Nitrogen [ESN]; methylene urea; SuperU; and 75% ESN, 25% urea blend) and untreated urea on forage accumulation, nutritive value, and legume persistence in a 'Wrangler' bermudagrass and 'Durana' white clover mixture. Nitrogen was applied at four rates (0, 112, 224, and 448 kg N ha-1) in two equal applications each year. By the second year, white clover stands were lesser at the greatest N rates. All enhanced efficiency N sources maintained white clover similar to the unfertilized grass-clover control, but only ESN improved white clover persistence over urea. Total season forage accumulation increased linearly with increasing N rates within all three growing seasons, but dry weather conditions in the last 2 yr resulted in less forage accumulation. Nutritive value decreased with maturity throughout the growing season, but ESN maintained clover in the pasture resulted in overall less fiber components and greater digestibility. Although there was no effect of N source on forage accumulation, the ability of ESN to maintain clover could make it a viable option for fertilization in bermudagrass-white clover mixtures. [ABSTRACT FROM AUTHOR]

Late summer application of nitrogen (N) fertilizer on stockpiled tall fescue [Schedonorus arundinaceus (Schreb.)] can improve forage yields. Using enhanced efficiency N fertilizers may be of benefit by reducing ammonia volatilization losses and promoting forage growth later in the growing season. This study evaluated the effect of different enhanced efficiency N formulations (Agrotain-treated urea, SuperU, and Environmentally Smart Nitrogen) and untreated urea on the yield and nutritive value of stockpiled 'KY-31' tall fescue over two stockpiling periods (2015-2016 and 2016-2017). Nitrogen was applied at four rates (0, 45, 90, and 134 kg N ha-1) in one application in late August prior to the beginning of the stockpiling period in Lexington, KY. During the 2015-2016 stockpiling period, forage yields increased with increasing N rates; forage yields ranged from 2,913 kg dry matter (DM) ha-1 when no N was applied up to 4,132 kg DM ha-1 when 134 kg N ha-1 was applied. Although forage yield was lower during the 2016--2017 stockpiling period, yield increased 75% even with the lowest N rate. Forage nutritive value was improved with increasing N rate. There were no differences in forage yield or nutritive value among enhanced efficiency N sources and standard urea. In summary, N applied in August improved stockpiled forage yield and nutritive value, regardless of N source. [ABSTRACT FROM AUTHOR]