Effects of Five Nitrogen Sources on Yield and Composition of Napier Grass

Abstract

The effects of applying 600 pounds of nitrogen per acre yearly from five sources on yield and composition of Napier grass growing on a latosol in the humid Mountain Region of Puerto Rico over a 3-year period were determined. Dry-matter yields and the calcium, phosphorus, manganese, and potassium content of the forage were unaffected by the nitrogen source. However, less protein was produced with urea and ammonium hydroxide than with ammonium sulfate, sodium nitrate, or ammonium nitrate, showing that the former are somewhat less efficient providers of nitrogen under the conditions of this experiment. Forage yields were lower but protein content was higher during the "winter" months of lower rainfall, shorter days, and cooler weather.