Oriella Romero Y.1 y Claudio Rojas G.1
The study was carried out at Carillanca Research Station (INIA) Temuco, Chile during 1989/90. The pasture was established on April 1982 with 16 kg/ha of fescue and 8 kg/ha of subclover and was annually fertilized with 54.4 kg of nitrogen and 18.4 kg of phosphorus as salitre and amonium phosphate. The aim of this study was to improve de subclover content in an old subelover/fescue mixture. Two mechanical treatments, with and without tyne plough and three fertilizer subtreatments were evaluated: check, 500 kg/ha of lime and 100 kg/ha of magnesium sulfate. The treatments were arranged in a split plot design with three replicates, The partial and the total dry malter production, botanical composition, plant number and nodulation were measured, The data obtained were submited to variance analysis, Duncan Test and Orthogonal Contrast using the statistical SAS program, The results showed that total D,M yield and the subclover content in the mixture were not influenced by the mechanical treatments (P > 0,05), The fertilizer treatments, lime and sulpomag, increased the dry mattar yietd and subclover cantent in the mixture from 13 to 14% in ralatian to the check (P < 0,05), The lime improved the nodule number and root size, The conventional soil analysis showed similar pH values for all treatments. The cation exchange capacity analysis (CIC) showed a decrease in the aluminium concentration in the soil by the lime application. It is concluded that the lime and Sulpomag improved the productivity of the subterraneam clover in the mixture, The mechanichal treatment decrease the subclover and promate the fescue content in the mixture.
Key words: subterraneum clever, Trifolium subterraneum, fescue, Festuca arundinacea, mixed pasture, yield, grassland management, fertilizer, IX Region.
1 Estación Experimental Carillanca (INlA), Casilla 58-D, Temuco, Chile.