Straw preservation reduced total N2O emissions from a sugarcane field

Post‐harvest biomass can be used as feedstock for energy production and alter N2O emissions from the soil, which is among the main issues determining bioethanol sustainability. To assess the effects of sugarcane straw return on gas emissions, we established a field experiment in which 0, 50, 75 or 100% (0, 5.65, 8.47 and 11.30 Mg/ha dry biomass, respectively) of the crop residues (straw) was left in the field during the first two ratoon crops. As fertilizer is applied in bands to sugarcane, we also investigated the contribution of different positions to the N2O emissions within the field. There was an interactive effect between straw and inorganic fertilizer, leading to a nonlinear effect of crop residues on the fertilizer emission factor (EF). However, straw consistently reduced N2O emissions from the field, acting mainly in the unfertilized areas in the field (P 100:1) on site might increase sugarcane production sustainability by reducing the greenhouse gas emissions from the field.