Sugarcane Bagasse ASH Application in Chemical and Organic Soil Attributes.

Brazilian potential in the electricity production from the burning of sugar cane bagasse signals to an environmental concern: the large production of residue. The São Paulo industries, especially in areas of ethanol and sugar production, are the largest generators of sugar cane bagasse ash residue. From varied composition, rich in macro and micro nutrients and some toxic metals in a lower concentration, the residue of carbonized biomass has been applied to the soil without any scientific criteria and supported by environmental law. In this sense, the objective of this study was to evaluate the effect of application of sugar cane bagasse ash rates in soil attributes and in the carbon (C) and nitrate leaching potential of the soil. The rates of ash provided linear increase in pH, organic C, P, K, Ca and Mg and reduction of potential acidity, and this effect was conditioned to the buffering capacity of each soil. The increase of the soil pH as from the ash application increased microbial activity and favored the availability of C existing in each soil. The movement of C and N provided by the ash did not change the structural groups of humic acid fraction of soil, but in soils with lower clay there was a greater movement of nitrate. The application of up to 80 ton ha^-1 of sugar cane bagasse ash positively affects the chemical attributes and biological activity of soil microorganisms, being the ash able to provide nutrients, add and make available C, regardless of soil texture. The C provided by ash decreases the humification of organic matter. The results showed that sugarcane bagasse ash has low residual effect and its effect persisted in the soil for a short time and does not affect the soil quality.