Cutting frequency effects on dry matter yield and nutritive value of cv. Camello and Cobra on shorth day-length

Abstract

Cultivars Camello and Cobra within the genus Urochloa are adapted to low infertile soils and drought tolerant.  Litle is known on its adaptation and yield in the different ecosystems of Puerto Rico. Experiments were conducted at the Agricultural Experimental Station of Lajas and Isabela, University of Puerto Rico, Mayaguez from October 2022 to May 2024. At Lajas, two cutting frequencies (6 and 8 weeks) effects on yield (kg ha^-1) and nutritive value [crude protein percentages (CP), acid and neutral detergent fibers (ADF; NDF), and in vitro digestibility (IVTD)] of cv. Camello and Cobra were evaluated. Design was a completely randomized design and data collected was analyzed using SAS statistical program. Means when significant were separated using Fisher LSD. Dry matter yield (DMY) was not affected by CF (p³0.05), but there was a cultivar effect (p£0.05) where cv. Camello (828 kg ha^-1) was higher than Cobra. Crude protein, ADF, NDF and IVTD did not differ by CF, but there were differences among cultivars for ADF, NDF and IVTD indicating better fiber and digestibility values for Cobra.  At Isabela, to improve DMY and nutritive value, perennial legume Stylosanthes (S. guianensis) and semi-annual Aeschynomene americana were tilled in Camello and Cobra stands.  Dry matter yield, botanical composition, CP, ADF and NDF were determined by harvesting every 6-wks.  Crude protein, NDF and FDA did not differ among associations. There was no difference between the cultivars regarding dry matter yield (DMY); however, for the legumes, the highest yield and proportion were observed with stylosanthes. A. americana did not persist by the fourth harvest.