Concentration of macronutrients in degraded tropical pasture in recovery rainy periods using wood

The objective of this study was to evaluate the average concentration of macronutrients in the rainy periods in Urochloa brizantha pasture fertilized with doses of wood ash associated with application management. Experiment was carried out in the field condition in two years at a degraded pasture in the Brazilian Cerrado (Tropical savanna). Experimental design was a 6x2 factorial scheme, corresponding to six doses of plant ash (0, 3, 6, 9, 12 and 15 t ha-1) associated with two treatments of wood ash: light application and superficial grade (without incorporation) with four replicates. The wood ash was derived from the industrial boiler combustion of plant materials. Average concentration of the macronutrients (nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur) were measured in plants. The analyzes of Marandu grass during the rainy season was evaluated from each evaluation year. The mean nutrient concentrations per year were calculated after the nutritional evaluation of four pasture cuttings. It was verified that the wood ash improves the nutritional quality of the recovering pasture. the wood ash doses between 9 and 12 t ha-1 presented greater nutrient concentration in plants. The incorporation of the wood ash in the soil assisted to better nutrient availability to the Marandu grass. The nutritive value of pasture depends on the applied ash quality as an alternative fertilizer.