Greenhouse gas emissions from green-harvested sugarcane with and without postharvest burning in Tucumán, Argentina

Abstract

Concentrations of greenhouse gases (GHG) in the atmosphere are increasing due to anthropogenic actions, and agriculture is one of the most important contributors. This study quantified GHG emissions from greencane harvested sugarcane with and without post-harvest burning in Tucuma´n (Argentina). A field trial was conducted in Tucuma´n during the 2011/2012 season using a randomised complete-block design with four replications. Treatments were: (a) harvest without sugarcane burning (neither before nor after), and (b) harvest with trash burnt after harvest. The method used to capture gases (CO2, CH4 and N2O) in the crop cycle was based on closed-vented chambers, while quantification was by gas chromatography. There were significant emission rates of CO2 and N2O during the sugarcane cycle in Tucuma´n, but no evidence of CH4 emissions or uptakes. N2O and CO2 emission rates were higher in the no-burning treatment than in the burnt, but only in part of the crop cycle. The former is apparently associated with the application of nitrogen fertiliser, while the higher CO2 emissions seem to be associated with trash retention. There were no significant correlations between environmental factors and emission rates. Although these results seem pessimistic, in the context of an entire crop GHG balance (including the emissions due to burning before or after harvest) green-cane harvesting without burning could effectively lead to a reduction of total GHG emissions during the crop cycle.