Irrigated sugarcane crops improve the quality of soil organic carbon over time

Abstract

The substitution of native vegetation in agricultural systems can cause several changes in the chemical and physical soil attributes, and in the dynamics of soil organic carbon. This study aimed to evaluate changes in soil physical attributes and carbon stock in soil organic matter fractions in irrigated sugarcane crops, as a function of land use and straw management practices over time, in the North of Minas Gerais State, Brazil. Four sugarcane fields with different ages and management systems were studied: Cane 6, Cane 7, Cane 8, and Cane 10. The data obtained were compared with a native vegetation area located near the sugarcane fields, and used as reference for unmanaged soil. In each system, soil samples were collected in the 0-10, 10-20, and 20-30 cm depth layers, to determine the physical attributes, the total organic carbon, and the physical fractions of the soil organic matter. We found that the sugarcane management with the maintenance of a part of the straw on the soil surface contributes to the preservation of the soil structure and the most stable fractions of organic carbon over time. However, in the regions with high annual mean temperature and in the irrigated systems, the soil tillage for the renewal of the sugarcane fields significantly decreases the total soil organic carbon.