Yield Response of a Tall Fescue‐White Clover Sward to Fertilization With Nitrogen, Phosphorus, and Potassium

Abstract

AbstractThe effects of different amounts of nitrogen, phosphorus, and potassium on productivity of a sward of ‘Kentucky 31’ tall rescue, Festuca arundinacea Schreb., and Ladino white clover, Trifolium repens L., were observed over a 4‐year period. The plant association was established by seeding on a low‐phosphorus Tilsit soil. Yields were obtained by clipping 5 to 7 times annually.Spring‐applied nitrogen at rates up to 270 kg per hectare (240 pounds per acre) did not increase total annual herbage production but resulted in larger yields during spring and early summer with proportionately less growth in late summer and autumn. Split applications of 135 or 270 kg of nitrogen per hectare annually improved herbage production to the extent of approximately 6 kg dry herbage per kg of applied nitrogen.Phosphorus additions markedly increased herbage growth, an annual application of 9.8 kg per hectare resulting in approximateley 1125 kg more dry matter per hectare. The application of potassium did not affect production initially, but a small yield response was observed the last year. Interactions between elements were relatively unimportant.The findings indicate the importance of judicious use of fertilizer, especially on soils of low crop‐yield potential, if livestock products are to be produced efficiently from grasslands.