EFFECTS OF PHOSPHORUS RATES AND SOIL CORRECTIVES ON NUTRITIONAL EFFICIENCY OF Stylosanthes guianensis

Abstract

In tropical soils, soil acidity can increase the efficiency of phosphated fertilization. The objective of this study was to evaluate the effect of two soil correctives and phosphorus rates on nutritional efficiency of Stylosanthes guianensis cv. Mineirão. The experiment was carried out in a greenhouse at the Department of Soil Science, Universidade Federal de Lavras (UFLa), Minas Gerais State, Brazil. A randomized blocks design was used in a 5x2 factorial arrangement, with five P rates (50 mg dm^-3, 100 mg dm^-3, 200 mg dm^-3, 400 mg dm^-3, and 800 mg dm^-3 of soil) and two soil correctives (lime and Ca and Mg silicate), with three replicates. The use of silicate for soil correction provided higher accumulation of Mineirão dry matter rates, from 50 mg dm^-3 to 420 mg dm^-3 of P. When phosphorus was associated with Ca and Mg silicate, the nutrients P, N, Ca, Mg, and Zn increased their use efficiency, resulting in a higher conversion rate of nutrients into biomass produced, except for the application of 800 mg dm³, due to nutritional imbalance in supplies of P and Zn. The Ca and Mg silicate provided greater recovery of applied P and should be used for pasture formation and management where Mineirão is used.

KEY-WORDS: Stylosanthes guianensis cv. Mineirão; Ca and Mg silicate; lime; phosphorus utilization.