Dados do Trabalho

Título

SOIL QUALITY INDEX OF VINASSE APPLICATION IN SUGARCANE AREAS

Resumo

Soil quality indices help quantify the impacts of management practices on the soil, providing information for producers and technicians in decision making. Thus, the aim was to use indicators to develop a general soil quality index (SQI) to quantify the impacts of long-term vinasse application on a clay soil (490 g/kg clay) and a sandy soil (80 g/kg clay). Soil samples were collected in the 0-10, 10-20 and 20-30 cm layers in areas without and with vinasse application for ten years. Four soil functions were developed to calculate the SQI: root environment quality (REQ), air/water ratio (AWR), soil chemical quality (SCQ), soil tolerance to erosion (STE). To calculate these functions, 12 soil indicators related to soil aggregation/structure and fertility were used. REQ was calculated using dry soil density, mean weight diameter of the aggregates, P content and Ca content. AWR was calculated using soil water storage capacity and soil aeration capacity. SCQ was calculated using organic carbon stock, K content, Mg content and sum of bases. STE was calculated using aggregate stability index in water and mineral-associated organic carbon. In the clay soil, vinasse increased the REQ, SCQ and STE functions by 10, 14 and 13%, respectively, besides not affecting AWR. Except for REQ, the long-term application of vinasse promoted greater benefits, proportionally, in the sandy soil, with increments of 30% in AWR, 25% in SCQ and 27% in STE. According to the SQI, long-term vinasse application increased by 8% the capacity of the clay soil to perform its functions, while in the sandy soil the increase was 22%. Long-term vinasse application is a sustainable alternative for improving soil quality in sugarcane areas, especially in sandy soils, promoting greater production potential for the crop and progress in soil conservation.

Palavras-chave

soil fertility; erosion; soil structure; sandy soil; clay soil.

Agradecimentos

The National Council for Scientific and Technological Development (CNPq) for the first author Research Productivity Fellowship