Composicion botanica y quimica de asociaciones de sorgo forrajero y leguminosas anuales.

摘要

The use of legumes and grass association represents a sustainable alternative for ruminant nutrition in the tropics. An experiment was conducted at the Isabela Sub-station of the Agricultural Experimental Station, Puerto Rico to assess the performance of forage sorghum (brown midrib BMR), Lablab, ( Lablab purpureus cv. 'Rongai' L) and velvet bean ( Mucuna pruriens cv. 'Vine 90 days' M) in monocrop and BMR intercropped with L and M. The variables were botanical and chemical composition [Neutral detergent fiber (NDF), acid detergent fiber (ADF) and crude protein (CP)] on dry matter yield basis. A randomized complete block in a split-plot design with 5 replications was used. Main plots were monocrops of BMR, L, and M, and associations of BMR-L and BMR-M, whereas the two cutting periods of 90 days (May and August) were subplots. The results indicated no differences (p>0.05) between the BMR intercropped and BMR in monoculture for the total dry matter yield. The values were 8.9, 8.8 and 8.4 ton/ha, BMR-L, BMR-M and BMR, respectively. Likewise, cutting periods were not significantly different (p>0.05), although the May harvest exceeded August by 0.6 ton/ha. Rongai revealed good regrowth, not varying in yield from the first cut, with botanical composition components having means values (p>0.05) of 2,7 and 3,9 ton/ha in intercropping and monoculture, respectively. Velvet bean presented the lowest (p0.05) yield, 2.8 and 1.3 ton/ha, for May and August, respectively. Its poor aggressiveness resulted in higher weed proportions. Both NDF and ADF (p>0.05) were not significantly different with values of 60.1 to 63.9% and 40.1 to 46.5%, respectively. However, there were differences in CP for mono and intercrops. Crude protein for L, M, and BMR were 14.1, 11.1, and 6.0%, respectively. Intercropped, CP for BMR-L and BMR-M were 9.8 and 9.1, indicating more than three units increase over BMR alone. In conclusion, BMR intercropped with Rongai and velvet bean improved nutritional quality from a ruminant nutrition perspective.