Impact of management practices on soil CO2 emission in sugarcane production areas, Southern Brazil

Abstract

The population increase in the next decades puts a direct pressure over aspects that appear to be paradoxical: more food and energy production together with environmental protection. In addition IPCC reports have pointed to the need of adaptation in several productive sectors, including Latin America, as higher temperatures and drier periods are expected. Hence, in near future agricultural production should be adapted and, if it is possible, should help the mitigation of atmospheric greenhouse gases, especially CO2. Despite all the efforts, new investigations should be conducted in order to understand how agricultural management and its variations would impact on soil CO2 emission (FCO2), and consequently in the soils potential for carbon sequestration. The objective of this project is to determine the impact of tillage and harvest management practices on FCO2 or soil carbon losses through CO2 in sugarcane production areas. Our study will focus FCO2 as much quantitatively as possible, by measuring it intensively in time and space close to the period that soil is bare and FCO2 is mostly related to the soil carbon decay only. Conceptual theory based on first Order decay models will be applied in order to understand the differences and similarities of FCO2 after tiIIage systems, including or not crop residues in soil surface. Spatial variability models will be treated as non isotropic and fractal theory will be applied to characterize anisotropy of FCO2 in sugarcane fields. Empirical models will be used in order to find a significant correlation between FCO2 and the spectral reflectance analysis of soils, among other properties. We firmly believe that the development of new and non conventional models, as proposed here are needed in order to improve our prediction capacity on FCO2 variability in space and time, and consequently on the predictions of soil carbon loss in those areas. (AU)