Conversion of low-to-high intensity pasture and to sugarcane fields: soil management impact

Abstract

There is an agreement about the potential of biofuels in decrease greenhouse gases emissions. The Brazilian ethanol has been used toward a more sustainable agriculture. However, "more sustainable" is linked with how the land conversion in sugarcane fields to supply the increase of ethanol demand will happened. Sugarcane expansion over low-intensity pasture is one of the most common land use change scenarios to increase ethanol production. The country is one of the largest beef producers and exporter in the world, hence, cattle ranching is an important economic activity. Brazil has extensive areas of low-intensity pastures. However, with the sugarcane expansion toward pasture areas and increase by food demand probably more areas with high-intensity pasture will be created. The management system used to land use change from pasture to sugarcane can impact soil structure, microbial diversity and, hence, greenhouse gases emissions. This project aimed assesses environmental impacts caused by sugarcane expansion over low-intensity pastures through analyses of soil and gas samples during six sugarcane stages (planting and five ratoon). First, the samples will process in laboratory to evaluation of soil organic matter dynamics, to calculate soil carbon manage index, as well as, carbon and nitrogen stocks. Simultaneously, the response of Acidobacteria subgroups to changes in soil physical and chemical parameters will assess. Also will be quantified greenhouse gases fluxes (carbon dioxide, methane and nitrous oxide), to evaluate total emissions due synthetic fertilizer application during low-intensity pasture to sugarcane and high-intensity pasture conversion, such dataset will be used in the DayCent model predicting future GHG emissions. The project approaches help us to obtain a better understanding about greenhouse gases emissions, organic matter dynamics and soil microorganism to obtain effective options against to global warming.