CONICET | Buscador de Institutos y Recursos Humanos

Eficiencias de establecimiento e implantación de pasturas templadas. Mixed temperate pastures should temporally be used as a winter crop by means of increasing sowing densities of the annual grass species and applying strategic nitrogen fertilizer. But higher sowing densities of the annual grass might contribute to perennial grasses and legumes displacement, modifying the floristic composition and the community stability. The aim of this study was to estimate establishment and implantation efficiencies resulting from two relative sowing densities of the annual and perennial grasses, and three fertilization treatments. A pasture composed by four species: Bromus willdenowii Kunth (-BW- annual grass), Dactylis glomerata L. (-DG-perennial grass), Trifolium pratense L. (-TP-) and Trifolium repens L. (white clover -TR-) was sown in the experimental field of FAUBA; 50 % of C3 grasses, 30 % of TP and 20 % of TR, on about 1700 viable seeds/m2. Sowing arrangement consisted of alternate rows of grasses and red clover, 0.175 m apart, with annual and perennial grasses in the same row and white clover sown in coverage. Twenty four experimental units of 6 m2 were established in a factorial arrangement of two relative sowing densities (35%DG+15%BW (>DG); 35%BW+15%DG (>BW)) and three fertilization treatments (without nitrogen and with 170 kg N.ha-1 in autumn or in winter) arranged in a randomized complete block design (n=4). Study variables were plant density (number of seedlings or plants/m2 -nº/m2-) registered in a fixed subplot of 0.09 m2 and sowing efficiencies (%) estimated by as the proportion of viable sown seeds.m-2 that performed in established seedling and implanted plants, two months and one year after sowing, respectively. Analyses of variance with a signification level of 5 % were used.