Chemical attributes, total organic carbon stock and humified fractions of organic matter soil submitted to different systems of sugarcane management

Abstract

Mechanized harvesting maintenance of trash from cane sugar and soil application of waste as vinasse and filter cake can improve the system of crop yield. Thus, this study aimed to evaluate the changes in the chemical, the stock of total organic carbon and humified organic matter fractions in an Oxisol cultivated with cane sugar with the following management systems: with sugarcane vinasse application (CCV), without application of burnt cane waste (CQS), with burnt cane vinasse application (CQV), with application of burnt cane filter cake (CQTF) and burnt cane with joint application of vinasse and filter cake (CQVTF). For reference we used an area of natural vegetation (NV), Cerrado sensu stricto. Treatment CQVTF showed improvement in soil chemical properties, increased inventory levels of total organic carbon – TOC (values ranging from 21.28 to 40.02 Mg ha-1) and humified fractions of soil organic matter in relation to other treatments. The CQS area at a depth of 0-0.05 m, showed the greatest losses of soil TOC stocks (56.3%) compared to NV. The adoption of management presented CCV and chemical attributes of the soil TOC stocks equivalent to those observed in areas with CQV CQTF and despite the short period of adoption (3 years). The TOC correlated with the sum of bases (r = 0.76 **), cation exchange capacity (r = 0.59 **) and base saturation (r = 0.63 **), while the humic acids (r = 0.40 **) fulvic acids (r = 0.49 **) and humin (r = 0.59 **) correlated with the cation exchange capacity of the soil. These results indicate that the preservation of trash in the management of cane sugar added to the application of vinasse and filter cake increases the TOC stocks promoting improvement in soil chemical properties.

Keywords

• Straw; Vinasse; Filter cake; Humic substances