Effect of Tillage, Residue Management and Nitrogen Fertilizer on Carbon Balance and Global Warming Potential in Maize Cultivation

This experiment was performed to evaluate the carbon (C) balance and global warming potential (GWP) as affected by tillage methods، maize residual management and nitrogen levels. For this purpose، a field experiment was conducted as row split-plot arrangement based on randomized complete block design with three replications in Ferdowsi University of Mashhad، Iran in 2011 and 2012. The experimental treatments were tillage systems (conventional and reduced tillage) and residual management (remaining and leaving of maize residual) assigned to main plots and different levels of urea fertilizer (0، 150، 300 and 450 kg. ha-1) was randomized as subplot in tillage treatment. The results showed that carbon sequestration was affected by residual treatment in both years and residual management × N fertilizer interaction in second year. Addition of residual in soil was caused to increasing 48% and 69% of C sequestration in first and second years، respectively. Across the treatments، residual management had the highest effect on C balance. So، C balance was positive in remaining maize residual and that was negative in leaving condition. GWP was higher under conventional tillage، residue remaining and higher N fertilizer levels in comparison with reduced tillage، residue leaving and lower N fertilizer application.