Fertilizer induced nitrous oxide emissions from Vertisols and Alfisols during sweet sorghum cultivation in the Indian semi-arid tropics

摘要

Nitrous oxide (N_2O) emissions from Vertisols and Alfisols during sweet sorghum cultivation in the Indian semi-arid tropics were determined using a closed chamber technique during the rainy season (June-October) of 2010. The study included two treatments, nitrogen (N) at a rate of 90 kg/ha and a control without N fertilizer application. The N_2O emissions strongly coincided with N fertilization and rainfall events. The cumulative N_2O-N emission from Alfisols was 1.81 N_2O-N kg/ha for 90 N treatment and 0.15 N_2O-N kg/ha for the 0 N treatment. Similarly, the N_2O-N emission from Vertisols was 0.70 N_2O-N kg/ha for 90 N treatment and 0.09 N_2O-N kg/ha for the 0 N treatment. The mean N_2O-N emission factor for fertilizer induced emissions from the Alfisols was 0.90% as compared to 0.32% for Vertisols. Our results suggest that the N_2O emissions are dependent on the soil properties. Therefore, the monitoring of N_2O emissions from different agro-ecological regions, having different soil types, rainfall characteristics, cropping systems and crop management practices are necessary to develop comprehensive and accurate green house gas inventories.