Response to calcium carbonate and phosphate fertilization of the mixture perennial ryegrass - white clover, on an Andisol. Nutrients uptake and forage quality

Ricardo Campillo R. 1

The effect of four levels of phosphorus (0, 33, 66 and 98 kg/ha), and four levels of calcium (0, 0.4, 0.8 and 1.6 ton/ha), on a perennial ryegrass white clover mixture, seeded on and Andisol, Vilcun series, Typic Dystrandept, was studied at the Carillanca Experiment Station (INIA, Temuco), during two years, in a complete randomized blocks desing, with four replications. Perennial ryegrass cv. Nui (18 kg/ha) and white clover cv. Huia, (3 kg/ha), previously inoculated with the specific Rhizobium and pelletized, were sown in september 1985. Accumulated N and P uptake were measured in the first and P and K, in the second growing season, together with total protein content and enzymatic in vitro digestibility. P and CaCO3 applications increased significantly (P < 0.01) accumulated P uptake; but there was no interaction or effect of seed pelleting, on accumulated N uptake the first growing season. Accumulated K uptake increased significantly (P < 0.01) with P levels, while CaCO3 and seed pelleting showed no effects. Mean total protein content changed between 15.4 and 18.6%, in PO, and 18.5 and 21.4%, in P66. Enzymatic in vitro digestibility changed between 72.5 and 73.3%, in PO, and 73.8 and 75.3%, in P66. This values show a clear influence of P fertilization and the excelent quality of the forage obtained.

1 Estación Experimental Carillanca (INlA), Casilla 58-D, Temuco, Chile.