Emissions of nitrous oxide in soil with sugarcane on straw

Abstract

The burning of sugarcane in the harvest has contributed to greenhouse gas (GHGs) emissions, which instigated the search for new forms of management less impacting to environment, such as harvesting sugarcane without burning. The objective of this research was to evaluate the nitrous oxide (N2O) emissions of the soil under sugarcane in different levels of straw and compare field emissions with emissions estimated by the “DeNitrification - DeComposition” (DNDC) model. The experiment was carry out in a Fluvic Plinthosol, using randomized block design, with four replications, with treatments corresponding to straw levels (0; 4.19; 9.54; 13.04 and 18.38 Mg ha-1). The emissions simulations (DNDC model) were compare with measured emissions. N2O fluxes were not affect by straw levels, indicating that the emissions were independent of the amount of straw accumulated on the soil at harvest. In the simulations, it was observed that the higher emissions were relate to the treatments with higher levels of straw. In general, the statistical indices indicated a good precision in the estimates of daily and accumulated flows, thus allowing the possibility of using this model to estimate soil N2O emissions under these conditions.