Fertilización del pasto elefante (Pennisetum purpureum) en Turrialba, Costa Rica. III. Efecto de niveles y formas de aplicación de P2O5

Abstract

The investigation was carried out at the Inter-American Institute of Agricultural Sciences of the OAS. Phosphorus fertilization was tested on Elephant grass (Pennisetum purpureum Schum.) growing on an alluvial soil in the Turrialba (Costa Rica) valley located at 602 m above sea level, with 2581 mm mean annual rainfall, and 22.5°C mean annual temperature. Four levels of phosphorus fertilizer in the form of triple superphosphate (46 per cent P2O5) namely, 0, 100, 200 and 400 Kg P2O5/ ha/year and two systems of application, namely broadcast and banded "in-the-row", were tested. Eleven grass cuttings were obtained every 7 to 9 weeks of growth each, except for the 10th cutting wich was performed after 11 weeks of growth due to a prolonged dry spell. The fertilizer application technique did not affect dry matter, protein production, plant. Ca and P contents, but the level of fertilizer application had influence in the response. Furthermore, phosphorous levels decreased protein and increased plant P contents. Dry matter production and plant protein contents decreased as the cuttings increased, after phophorous fertilization. Plant P and Ca content also varied significantly due to cuttings.