Forage productivity and quality of Cenchrus clandestinus Morrone in two pastoral systems in the Colombian Andes

Objective: To determine the effect of Alnus acuminata Kunth on the yield and nutritional quality of Cenchrus clandestinus (Hochst. ex Chiov.) Morrone in two pastoral systems in the Colombian Andean mountain range. Materials and Methods: For the evaluation of the yield and quality of the forage biomass of C. clandestinus, an experiment was conducted in a silvopastoral system and a pasture without tree cover. A complete randomized block design was established, defined by the presence or absence of A. acuminata, with pasture cutting frequency every 35 or 45 days. Four treatments and three replicas were defined to determine statistical differences. An analysis of variance and Tukey's test were performed. The variables green forage production, dry matter, crude protein, neutral detergent fiber, acid detergent fiber, dry matter digestibility and net lactation energy were evaluated. Results: The experimental units of the silvopastoral system were statistically superior to the uncovered pasture treatments. They showed higher yields, in terms of green forage and dry matter, and stood out for their nutritional attributes of crude protein, digestibility and net lactation energy. The treatment with the incidence of the forest species A. acuminata and pasture utilization at 45 days recorded the highest averages in green forage and dry matter (19 360,3 and 123,5 kg) and the best nutritional quality, followed by the silvopastoral system with cutting frequency every 35 days. Conclusions: The silvopastoral system obtained the best results in production and quality of C. clandestinus grass, which indicates the positive impact of the tree species on the evaluated indicators, due to the different interactions that the tree promoted in the agroecosystem. Key words: agroforestry, Alnus acuminata, agricultural productivity, nutritional value