Effect of Heavy Rates of Fertilization on Beef Production and Carrying Capacity of Napier Grass Pastures over 5 Consecutive Years of Grazing Under Humid Tropical Conditions

Abstract

Intensively managed Napier grass pastures on steep slopes in the humid mountain region of Puerto Rico grazed by young growing cattle over a 5-year period, produced an average of 947,1,281 and 1,582 pounds of gain in weight per acre yearly when fertilized annually with 1,600, 2,800 and 4,000 pounds of 14-4-10 fertilizer per acre, respectively. The pastures carried the equivalent of 2.22-, 2.89- and 3.58 six-hundred-pound steers per acre throughout the year and produced 6,890, 8,960 and 11,100 pounds of total digestible nutrients per acre yearly at the 1,600-, 2,800- and 4,000- pound fertilizer levels, respectively. Daily gains per head were not affected by level of fertilization, and averaged 1.31 pounds. At the 4,000-pound fertilizer rate the pastures maintained a minimum of 3 head per acre and produced 1,582 of liveweight worth about $475 at current prices or $315 above fertilizer costs.