ABSTRACT
EFFECT OF FOUR LEVELS OF PHOSPHORUS ON BEEF PRODUCTION OF A WHITE CLOVER-PERENNIAL PYEGRASS PASTURE. I. PRODUCTION

Germaán Klee G.1, Ignacio Ruiz N.2 y Ernesto Jahn B.2
 
During a 5 years period (1967 - 1972) the effect of four levels of maintenance fertilization (0, 50, 100 and 200 Kg P2O5/ha/year) on the production of a white clover (Trifolium repens L.) - ryegras (Lolium perenne L.) pasture, was evaluated. The soil is of a volcanic ash type ("andept"), located at "Humán" Experiment Substation (Los Angeles, Chile). The fertilizer was topdressed as triple superphosphate. Each treatment had 2 replicates, of one hectare each, which were utilized with a "put and take" system, using Holstein steers weighing 200-300 Kg at the beginning of each grazing season. Daily weight gains were not significantly (P > 0.05) different between the four treatments. Stocking rate increased with increasing phosphate fertilization. The response curve was: Y = 900 + 86 log (X + 1), where Y = steer-days/ha and X = kg P2O5/ha/year. There was a great increase in stocking rate when phosphate was increased from 0 to 50 Kg P2O5/ha. Liveweight gain per hectare was expresed as: Y = 812 + 120 log (X + 1), where Y = liveweight gain in Kg/ha/year and X = Kg P2O5/ha/year. the greastest increase in production was obtained when phosphate was raised from 0 to 50 Kg/ha/year. Soil P increased exponentially with increased phosphate fertilization.
Keywords:
1Ing. Agr., Subestación Experimental Humán, Instituto de Investigaciones Agropecuarias (INIA), Casilla 767, Los Angeles, Chile.2Ing. Agr., Ph. D., Estación Experimental Quilamapu, Instituto de Investigaciones Agropecuarias (INIA), Casilla 426, Chillán, Chile.