N_2O emission from soil-vegetable system and impact factors in Chengdu Plain of Sichuan Basin

N2O emission from soil-vegetable system in Chengdu Plain of Sichuan Basin was measured using static chamber/gas chromatograph techniques from April 11, 2005 to May 8, 2006. N2O emission characteristics and the impact factors of N application, soil moisture, soil temperature and vegetable growth were investigated, which provide basic data for accurate estimation of N2O emission from the vegetable land. The mean emission flux of N2O were (58.7±13.9),(83.8±16.2)μg/(m2·h) without N application and with application of 200kg N/hm2, respectively, in the soil-vegetable ecosystem. The total N2O loss derived from N applied accounted for 0.38%. The seasonal variation of N2O emission was double-pulses during vegetable growing period. N2O emission fluctuated at low level at fallow but increased remarkably due to soil tillage. The effects of N application on N2O emission enhanced with increasing of N application rate. N2O fluxes were negatively related to soil moisture in vegetable growing period and at fallow. The positive relationship between N2O emission and soil temperature was significant in spring vegetable season but not in winter vegetable season and at fallow. N2O emission flux was higher in the vegetable land than that in cropland without N application, meanwhile, total N2O loss derived from N application in vegetable land was slight higher than that in cropland under N application. The N2O emission rate from the vegetable land was higher than that in the cropland in Chengdu Plain of Sichuan Basin.