Influence of Nitrogen Sources and Time of Cutting on Yield and Protein Content of Napier (Merker) Grass

Abstract

Ammonium sulfate, urea, and Nitroform were evaluated as nitrogen sources for Napier (Merker) grass (Pennisetum purpureum), as influenced by liming and harvesting interval. The results indicated that: 1. The annual mean yield of green grass per acre was increased by longer harvest or cutting intervals. The 9-week harvest interval gave significantly more tonnage of forage than did the 6-week interval, but the 12-week interval was not significantly better than the 9-week. 2. There was a significant increase in forage tonnage attributable to nitrogen sources used, over the no-nitrogen treatment at all harvest intervals. 3. Ammonium sulfate gave the highest yields of green forage and percentages of protein for the average of the three harvest intervals. 4. The protein content of Napier grass decreased with increasing harvest intervals, and none of the nitrogen sources used prevented or modified this decrease. 5. Liming did not significantly increase yields of green forage per acre or percentages of protein.