Effect of nitrogen and phosphorus fertilizers on some components of nutritive value of dwarf elephantgrass

Abstract

Crude protein (CP), calcium (Ca), and phosphorus (P) concentrations and in vitro dry matter digestibility (IVDMD) of leaves, stems, and whole plants of sprinkler‐irrigated dwarf elephantgrass (Pennisetum purpureum) cv. Mott as affected by the factorial combinations of nitrogen (N) (0, 150, 300, and 450 kg N ha^‐1 year^‐1) and P (0, 50, and 100 kg P₂O₅ ha^‐1 year^‐1) fertilization rates were evaluated in a tropical dry forest in the State of Zulia, western region of Venezuela. A randomized complete block design with three replications was used. Soil was a low‐fertility sandy‐loam Alfísol (Udic Paleustalf) with pH of 6.1. Data from eight cuttings carried out at 45‐day intervals were used. Only Ca and P concentrations in stems were affected by N fertilization. Phosphorus fertilization influenced (P>0.05) PC and P contents in leaves, IVDMD in stems, and Ca and P concentrations in both stems and whole plants. Overall mean IVDMD and CP, Ca, and P contents were: leaves, 62.9, 8.75, 0.39, and 0.30%; stems, 64.1, 7.38, 0.20, and 0.38%; and whole plants, 61.3, 8.13, 0.26, and 0.33%, respectively. Even though CP values were not very high, moderate production levels can be expected from ruminants fed this species since other components of its nutritive value can be regarded as adequate.