Comparison of Six Stylosanthes Cultivars and Digitaria Milanjiana in the Humid Mountain Region of Puerto Rico

Abstract

Five Stylosanthes guianensis cultivars (Fine Stem, Endeavour, Schofield, USDA PI 361877, and USDA P1279603), Stylosanthes gracilis USDA Pl261266, and Digitaria milanjiana USDA PI 299699 were grown in small replicated plots at the Corozal Substation in the humid mountain region. All legumes were established in a period of 134 days and nodulated freely. The swards were harvested every 45 (9 cuttings) and 65 days (6 cuttings) at 20 cm above ground level, respectively. Forage yields and chemical composition were measured in each plot. Subsequently the same 65-day cutting interval swards were subjected to 5 additional cuttings, whereas the 45-day swards were substituted by a 79-day interval and 4 cuttings. D. milanjiana outyielded the 6 stylos in dry forage at the 3 cuttings intervals. Highest yielder among the stylos was cultivar Fine Stem, which produced total dry forage yields of 18,522, 18,936, and 11,329 kg per ha in 395-, 390-, and 316-day periods at 45-, 65-, and 79-day harvest intervals, respectively. At 45-day intervals, cultivar Fine Stem yielded more crude protein than the rest of the stylo cultivars. There was no difference in protein yields between cultivar Fine Stem and D. milanjiana at the 45- and 65-day harvest intervals. Stylo cultivars and D. milanjiana produced similar crude protein yields at the 79-day intervals. The stylo cultivars were higher in nitrogen, calcium and magnesium contents than D. milanjiana at all harvest intervals.