Effect of Three Harvest Intervals on Yield and Nutritive Value of Seven Napiergrass Cultivars

Abstract

Seven Napier or elephant grass cultivars (Pennisetum purpureum Schum.) were evaluated at the University of Puerto Rico Corozal Agricultural Experiment Substation for 2 years to measure the effect of 30-, 45-, and 60-day harvest intervals on green forage (GF), dry forage (DF), and crude protein (CP) yields, leaf/stem ratio, and chemical composition. As the grasses advanced in maturity from 30 to 45 and from 45 to 60 days, GF, DF, and CP yields increased in all cultivars. Significant (P < .05) differences occurred among cultivars as to GF, DF, and CP yields during the 2-year period. The highest DF yields were obtained by cultivars 13079, 13078, 7353, and 7350. Significant (P < .05) differences also occurred among cultivars as to GF and DF yields during the short-day and dry-month periods of the year. leaf/stem ratio was higher during the short-day and dry-month periods, and lower during heavy rainfall periods. At the 45-day harvest interval, cultivar 13079 was highest in neutral-detergent fiber, acid-detergent fiber, and lignin contents, but lowest in CP and estimated digestibility contents.