农作物秸秆还田作为农田土壤和养分管理的推荐做法之一,对于土壤有机碳(SOC)固定和CO2减排具有重要意义。本研究利用环境政策综合气候模型(EPIC)模拟了4种作物秸秆还田情形下2001年至2010年中国农田表层土壤有机碳变化及其空间格局。模拟结果显示,秸秆完全移除(CR0%)下的土壤有机碳损失为28.89 Tg yr–1,当前30%的秸秆还田(CR30%)能够减缓22.38 Tg C yr–1的碳损失。若秸秆还田率从30%提高至50%(CR50%)乃至75%(CR75%),中国农田表层土壤将变为净碳汇。中国农田表层土壤固碳潜力在CR50%和CR75%情形下分别可达25.53 Tg C yr–1和52.85 Tg C yr–1,且在不同农业区存在空间异质性。单位面积土壤固碳潜力在西北和华北地区最高,而华东最低。华北地区具有最高的区域固碳潜力。在这十年间,CR50%和CR75%情形下增加的土壤表层有机碳相当于减少了1.4%和2.9%的中国CO2排放总量。总之,我们建议鼓励我国农民将原本直接焚烧或用作家用燃料的秸秆返还田间以改善土壤性质和减缓大气CO2增加,尤其是华北地区更应推行这一举措。
Crop-residue return is a recommended practice for soil and nutrient management and is important in soil organic carbon(SOC)sequestration and CO2 mitigation.We applied a process-based Environmental Policy Integrated Climate(EPIC)model to simulate the spatial pattern of topsoil organic carbon changes from 2001 to 2010under 4 crop-residue return scenarios in China.The carbon loss(28.89 Tg yr–1)with all crop-residue removal(CR0%)was partly reduced by 22.38 Tg C yr–1 under the status quo CR30%(30% of crop-residue return).The topsoil in cropland of China would become a net carbon sink if the crop-residue return rate was increased from 30%to 50%,or even 75%.The national SOC sequestration potential of cropland was estimated to be 25.53 Tg C yr–1 in CR50%and 52.85 Tg C yr–1 in CR75%,but with high spatial variability across regions.The highest rate of SOC sequestration potential in density occurred in Northwest and North China while the lowest was in East China.Croplands in North China tended to have stronger regional SOC sequestration potential in storage.During the decade,the reduced CO2 emissions from enhanced topsoil carbon in CR50%and CR75% were equivalent to 1.4% and 2.9%of the total CO2 emissions from fossil fuels and cement production in China,respectively.In conclusion,we recommend encouraging farmers to return crop-residue instead of burning in order to improve soil properties and alleviate atmospheric CO2 rises,especially in North China.
Journal of Resources and Ecology
The National Key Research and Development Program of China (2017YFC0503803)
General Program of National Natural Science Foundation of China (41571192)
The National Key Research and Development Program of China (2016YFA0600202)
Science and Technology Planning Project of Hebei, China (17390313D).
soil carbon sequestration
First author:CHEN Jinghua,E-mail:email@example.com;Corresponding author:WANG Shaoqiang,E-mail:firstname.lastname@example.org.