中国蔬菜生产体系N2O排放的空间差异及减排措施OA北大核心CSTPCD

[Objectives]We studied the N2O-N emission factors in various vegetable species,cultivation modes,and regions in China,and assessed the effects of widely used measurements on reducing N2O emission.[Methods]Field observation data were collected from research papers focusing on N2O emission and emission reduction in vegetable production areas of China.The emission factors(EF)were calculated according to the vegetable species and production areas under greenhouse and open field conditions,respectively.The effect of managements on reducing soil N2O emission was summarized.The correlation between N2O emission reduction and vegetable yields was calculated as well.[Results]The EFs of open field vegetable production in North China,Northwest China,the middle and lower reaches of the Yangtze River,Southwest China,and South China were 1.27%,0.83%,1.20%,1.54%,and 5.57%,respectively,with an average of 1.23%across the whole country.Notably,the EF in South China was 6.7 times of that in Northwest China.For greenhouse vegetable production,the EFs in North China,Northwest China,and the middle and lower reaches of the Yangtze River were 0.99%,0.65%,and 1.13%,with an average of 0.88%across the whole country.Furthermore,the EFs in leafy,fruit,tuber,and root vegetable production were 1.72%,1.03%,0.92%,and 1.28%in open field,and in greenhouse leafy,fruit and tuber vegetable production were 0.44%,0.95%,and 0.41%,respectively.Compared to conventional fertilization methods,N rate reduction,biochar application,optimized irrigation,and nitrification inhibitor application reduced N2O emissions by 41.3%,29.1%,37.4%,and 27.9%,respectively.Combination of optimized irrigation with N rate reduction,and nitrification inhibitor with N rate reduction achieved N2O emission reduction ranging from 45.8%to 57.3%.All the nitrification inhibitors displayed comparable N2O reduction rates of 26.5%to 29.7%.Application of biochar in rates of≤10,10-20,20-30 and 30-40 t/hm2 reduced N2O emission by 31.7%,24.3%,38.0%,and 26.8%,respectively.Reducing nitrogen rate of≤20%,20%-30%,30%-40%,40%-50%,>50%were observed N2O emission reduction by 36.9%,37.5%,29.7%,71.3%,and 39.4%,respectively,compared to conventional N rate and management practices.[Conclusions]The N2O-N emission factors are significantly different among vegetable production areas and vegetable species under both green house and open field conditions in China.More attention should be paid to N2O emission in the multi-maturing vegetable systems in the subtropical climate areas.EF reducing measurements should be chosen according to vegetable species for relatively constant effect across the whole country.Reducing 40%-50%of conventional N fertilizer input,applying nitrification inhibitors,and biochar could reduce N2O emission effectively,and their combining use could achieve a win-win scenario,without obvious influence on vegetable yields.