ChileanJAR

From June to December 1986, at the Carillanca (INIA) Exp. Sta. (lat. 38° 41 S; long. 72° 25 W), the characterization of a pasture of LoIium perenne and Trifolium repens was conducted. The 14 years oid pasture, for the previous 3 years, had been deferred or grazed by dairy cows, during winter (May-August). The objective of the experiment was to evaiuate the effect of these previous treatments, on the production of dry matter, yieid components,botanical composition, and forage quaiity. Four replicates, of an area of 1 ha each, were used in a randomized block design. During the experimental period, the pastures were not grazed in winter, but were rotationaiy utilized during the spring season. Dry matter acumulation during winter was not statisticaily different (P > 0.05), with 1,480 kg D.M./ ha, for the deferred treatment, and 1,470 kg D.M./ha, for the grazed treatment. Dry matter production untiil December, was not affected by the treatments (P > 0.05), with values of 7,447 and 8,210 kg D.M./ha, respectiveiy. Botanical composition in winter and spring were not significantly different (P > 0.05). A reduction in the porcentage of ryegrass and other winter grasses was observed at the beginning of summer, while dead matter increased considerably. Yield components of ryegrass and white dover were not significantly different between treatments (P > 0.05), but a statisticaiiy significant effect due to season was observed (P < 0.05), except on the weight of dover ieaves/m². Forage quaiity was not significantly affected by treatments (P > 0.05), but a significant seasonai vanation was observed, which was related to higher ieveis of dead matter and to the advance in maturity of the pasture.