Wood ash on the fertilization of marandu grass in Brazilian cerrado soils

Wood ash can be an alternative fertilizer and soil corrective measure, directly contributing to the production of pastures. The objective of this research was to evaluate the growth and production of marandu grass fertilized with wood ash and grown in two soil classes of the Brazilian Cerrado. The experiment was conducted in a greenhouse during the period from December, 2012 to May, 2013. The experimental design was completely randomized in a factorial 2 × 6, corresponding to two soil classes (Ultisol and Oxisol) and six doses of wood ash (0, 3, 6, 9, 12 and 15 g dm-3), with six replications. Pots with soil volume of 5 dm3 were used with five plants. Three cuts were performed in the shoot of plants in a 30-day interval and at each cut was the plant height, dry mass of leaves and stems and the leaf/stem ratio evaluated. The results were submitted to analysis of variance and, when significant, the qualitative factors (soil classes) were submitted to the Tukey test and the quantitative factors (wood ash doses) subjected to regression analysis, both at 5% probability. The wood ash as fertilizer provides greater growth and dry matter production of marandu grass grown in Ultisol and Oxisol. The use of wood ash as fertilizer may be an alternative for the destination of this waste, and it can provide a reduction of mineral fertilizer and consequently of pasture production costs in the Brazilian Cerrado. Key words: Solid waste, alternative fertilizer, Brachiaria brizantha, ultisol, oxisol.