Response of Stargrass to Fertilizer and Solid Cattle Manure in Puerto Rico

Abstract

A field experiment conducted in 1981 and 1982 at the Corozal Substation to determine the effects of solid cattle manure on the green forage, dry forage, and crude protein yields of stargrass (Cynodon nlemfuensis var. nlemfuensis) and on soil composition, showed that after 720 days the maximum manure application, without supplemental nitrogen fertilization, increased dry forage and crude protein yields significantly over the unfertilized control. Solid manure 65% dry matter and 1.6% nitrogen, .10% phosphorus, and .34% potassium; was applied at six rates (2,800, 5,600, 11,200, 16,800, 22,400 and 31,360 kg/ha/year) Stargrass harvested every 45 days. Manure treatments were supplemented with commercial fertilizer to provide 504, 73, and 336 kg/ha/year of N, P and K, respectively. Two check treatments were included: one received 3,360 kg/ha/year of 15-5-10 fertilizer as a standard fertilization and the other received neither fertilizer nor manure. Surface-applied manure at rates of 2,800, 5,600, 11,200, 16,800 and 22,400 kg/ha/year, supplemented with N, P and K, and the fertilized control gave similar dry forage yields. Stargrass P content tended to increase with manure applications, but K, Ca and Mg contents were similar to the standard fertilization. Soil available P and exchangeable K tended to increase with manure applications.