Effect of Three Harvest Intervals on the Yield and Protein Content of Ten Brachiarias

Abstract

Ten Brachiarias were evaluated during an 18-month period at various harvest intervals at the Corozal Substation for yields of green forage (GF), dry forage (DF), and crude protein (CP), and for contents of (CP) and dry matter (DM). At the 30-day harvest interval, the most productive introduction was Brachiaria humidicola (P.I. 299497), with 119,567 and 22,548 kg/ha/year of GF and DF, respectively. Para grass (B. mutica) and B. ruziziensis (P.I. 247404) had the highest DM content, 22.5%. Para grass also had the highest CP yield, 2,961 kg/ha/year. At the 45-day harvest interval, B. humidicola (P.I. 299497) had the highest GF yield, 160,459 kg/ha/year, while para grass had the highest DM content, 22.5%. Para grass was the highest DF yielder, with 31,338 kg/ha/year, and B. humidicola (P.I. 299497) was the highest CP yielder, with 3,787 kg/ha/ year. At the 60-day harvest interval, B. humidicola (P.I. 299497) was the highest GF yielder, with 146,318 kg/ha/year, while para grass had the highest DM content and DF and CP yields, 25.9%, 36,946 kg/ha/year, and 3,264 kg/ha/ year, respectively. The GF and DF yields increased with length of the harvest interval. The DM contents, however, were similar at the 30- and 45-day intervals and higher at the 60-day interval. The CP yields increased from 2,651 kg/ha/year at the 30-day harvest interval to 2,912 kg/ha/year at the 60-day harvest interval. The DF and CP yields of B. humidicola (P.I. 299497), para grass, signal grass (B. brizantha, P.R. P.I. 1525), and others were excellent and compared favorably with those of the recognized top-yielding grasses in Puerto Rico.