Productivity of Intensively Managed Pastures of Five Grasses on Steep Slopes in the Humid Mountains of Puerto Rico

Abstract

The productivity, in terms of carrying capacity and of beef yields, of intensively managed, well-fertilized pastures of five grasses on steep slopes in the Mountain Region of Puerto Rico with annual rainfall of 63 inches, was determined. Pangola, Guinea, and Napier grass pastures produced similar high yields, averaging 1,058 pounds of weight gain and 7,500 pounds of total digestible nutrients, equivalent to a carrying capacity of 2.4 600-pound steers per acre yearly over a 4-year period. The young cattle grazed for periods of a full year averaged 1.3 pounds of weight gain daily. No weeding was necessary and there was no problem with "manure spots" in these pastures receiving 1 ton of 14-4-10 fertilizer per acre yearly in four equal applications. There was little compaction of the soil by trampling, and loosening the surface soil after 4 years of intensive grazing did not increase yields of any of these grasses. Quality of the Pangola, Guinea, and Napier grass forage was in all cases excellent and varied little with season of the year or with grass species. Crude-protein content of samples obtained throughout the year by simulated grazing averaged 18.1 percent, phosphorus 0.22, lignin 8.1, and calcium 0.62 percent for Guinea and 0.32 percent for Napier and Pangola grasses. Para grass and molassesgrass pastures were definitely inferior to Pangola, Guinea, and Napier grasses, producing only 636 pounds of weight gain, and 5,030 pounds of total digestible nutrients per acre yearly.