Effect of Harvest Interval on Yields of Four Sudan Grass Sorghum Crosses with Irrigation on the South Coast of Puerto Rico

Abstract

Yields of the Sudan grass-sorghum hybrids Space Maker, Grazer A, Sordan 70, and Graze and Bale averaged 23,028, 39,815 and 54,810 kg of dry forage/ha/yr when harvested every 30, 45 and 60 days, respectively, over a one year period with irrigation. Crude protein percentage of the forage averaged 9.0, 6.2 and 5.0% for the 30, 45 and 60 days cutting intervals, respectively. Sordan 70 and Grazer A were the highest yielders with 30. or 60-day harvest intervals. Sordan 70 outyielded all the other forages at the 45-day harvest interval. All the forages had similar crude protein contents at the various cutting intervals except Sordan 70 that had a lower protein content than the other forages at the 30. and 60-day cutting intervals. All the forages produced similar yields of crude protein at the various cutting intervals except that Sordan 70 which produced more total protein than the other grasses at the 45-day harvest interval. The very high yields produced by these forages show that the semiarid irrigated region of Puerto Rico can be used to grow forage to supplement pastures in nearby grazing lands during the annual dry season.