SOIL QUALITY IN AREAS OF LAND USE CHANGE FOR SUGARCANE CULTIVATION IN SOUTH-CENTER OF BRAZIL - data for the evaluation of environmental sustainability of ethanol

Abstract

The environmental impacts caused by the land use change (LUC) with conversion of native vegetation and pasture areas for sugarcane have generated questions facing the environmental sustainability of Brazilian ethanol production. In this context, the soil quality (SQ) has been identified as a key indicator to compose protocols and evaluate such impacts in the producing systems. Thus, the objective of the project is to evaluate the impacts of land use change (LUC) for sugarcane cultivation on chemical and physical soil quality properties in the south-center region of Brazil. Additionally, a soil quality index (SQI) will be developed for assessing areas where LUC occurs for the cultivation of sugarcane for ethanol production. The study will be conducted in three chronosequences where LUC was promoted to sugarcane cultivation. In each one of these cronossequences, the native vegetation was converted into pasture and then to sugarcane. The selected study sites are placed in Jataí-GO, Valparaiso-SP and Ipaussu-SP, in south-center, Brazil. In each area, soil samples will be collected in nine sites considering three soil depths (0-10, 10-20 and 20-30 cm). From the samples collected, will be determined in the laboratory chemical indicators (organic carbon, macro and micronutrients and acidity indicators) and physical (texture, density, porosity, available water, penetration resistance, hydraulic conductivity and soil aggregation). Biological indicators (soil fauna (indexes), diversity and microbial biomass, enzyme activity) will be obtained from other projects developed concurrently by the research group. The SQ indicators also will be evaluated using the Soil Quality Test Kit. All costs involved in obtaining chemical and physical indicators will be inventoried, to obtain the cost-effectiveness of these each one of these assessments in SQ. Initially, the data will be analyzed using the univariate statistical methods (descriptive statistics, analysis of variance, means comparison test) in order to analyze the impacts of LUC over the soil chemical-physical properties. Posteriorly, we will use the multivariate statistical methods (component principal analysis and factor analysis), to promote a conjunct analysis involving chemical, physical and biological indicators, and define a minimum data set needed to evaluate the SQ. Finally, considering the five major soil functions will be developed and compared three IQS, calculated from i) all indicators evaluated, ii) indicators present in the minimum data set and iii) indicators obtained through the use of the Soil Quality Test Kit. We expect that results generated by this research project can contribute in assessments of environmental sustainability and suggest strategies for mitigating the environmental impacts caused by the expansion of the Brazilian sugarcane industry.