Journal of Integrative Agriculture ›› 2023, Vol. 22 ›› Issue (7): 2233-2247.DOI: 10.1016/j.jia.2022.12.005

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中国南方种植利用绿肥对稻田土壤碳固持和碳足迹的影响

  

  • 收稿日期:2022-09-05 接受日期:2022-10-28 出版日期:2023-07-20 发布日期:2022-10-28

The potential of green manure to increase soil carbon sequestration and reduce the yield-scaled carbon footprint of rice production in southern China

GAO Song-juan1, LI Shun1, ZHOU Guo-peng2, CAO Wei-dong2#   

  1. 1 College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, P.R.China
    2 Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100018, P.R.China

  • Received:2022-09-05 Accepted:2022-10-28 Online:2023-07-20 Published:2022-10-28
  • About author:GAO Song-juan, E-mail: gaosongjuan@njau.edu.cn; #Correspondence CAO Wei-dong, Tel: +86-10-82109622, E-mail: caoweidong@caas.cn
  • Supported by:
    This study was supported by the National Key Research and Development Program of China (2021YFD1700200) and the earmarked fund for China Agriculture Research System (CARS-22).

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摘要：

中国南方稻田绿肥种植和利用已有数千年历史，维持了区域土壤肥力和水稻生产。但目前绿肥对稻区土壤碳固持和碳足迹的定量化研究少有报道。本研究将长期定位试验与Meta分析结合，定量研究了绿肥提高中国南方稻田土壤碳固持和减少碳足迹的潜力。研究表明，与冬闲相比，冬种绿肥处理可在减少40%的氮肥下维持水稻产量，同时土壤表层碳固持速率为1.62 Mg CO2-eq ha-1 yr-1。不同试验站的总碳足迹范围为7.51~13.66 Mg CO2-eq ha-1 yr-1， 其中甲烷是最主要组分，占总量的60.7%-81.3%。绿肥-稻田模式降低了稻田生产系统31.4%的非直接碳足迹排放（主要为氮肥），提高了19.6%的直接碳足迹排放（主要为甲烷）。绿肥的甲烷排放因子（EFgc）在低和高甲烷排放情景下分别为5.58%和21.31%。在低排放情景下，土壤碳库的增加可抵消增加的稻田甲烷排放；而在高排放情景下，土壤碳库的增加不足以抵消增加的稻田甲烷排放。当EFgc小于9.20%时，绿肥可同时增加土壤碳库和减少系统碳足迹。EFgc值的大小主要受绿肥翻压量和稻田水分管理影响，说明优化翻压量和田间水分管理是提高中国南方稻田绿肥田土壤碳固持和减少碳足迹的关键。

Abstract: Green manure (GM) has been used to support rice production in southern China for thousands of years. However, the effects of GM on soil carbon sequestration (CS) and the carbon footprint (CF) at a regional scale remain unclear. Therefore, we combined the datasets from long-term multisite experiments with a meta-analysis approach to quantify the potential of GM to increase the CS and reduce the CF of paddy soils in southern China. Compared with the fallow– rice practice, the GM–rice practice increased the soil C stock at a rate of 1.62 Mg CO2-eq ha–1 yr–1 and reduced chemical N application by 40% with no loss in the rice yield. The total CF varied from 7.51 to 13.66 Mg CO2-eq ha–1 yr–1 and was dominated by CH4 emissions (60.7–81.3%). GM decreased the indirect CF by 31.4% but increased the direct CH4 emissions by 19.6%. In the low and high CH4 emission scenarios, the CH4 emission factors of GM (EFgc) were 5.58 and 21.31%, respectively. The greater soil CS offset the increase in GM-derived CF in the low CH4 scenario, but it could not offset the CF increase in the high CH4 scenario. A trade-off analysis also showed that GM can simultaneously increase the CS and reduce the total CF of the rice production system when the EFgc was less than 9.20%. The variation in EFgc was mainly regulated by the GM application rates and water management patterns. Determining the appropriate GM application rate and drainage pattern warrant further investigation to optimize the potential of the GM–rice system to increase the CS and reduce the total CF in China.

Key words: green manure , paddy soil ,  soil carbon sequestration ,  carbon footprint