Supported by the National Science Foundation of China (No. 41971050), the National Science Foundation of Fujian Province, China (No. 2019J01660) and Young Foundation of Ministry of education, humanities and social science (No. 21YJC630090)
明确不同秸秆还田量对土壤“碳汇”的贡献大小是合理制定农业碳中和措施的基础。以我国典型亚热带地区——福建省水田土壤为研究对象，基于2016年15 833个土壤样点实测数据和目前该地区最详细的1:5万大比例尺土壤数据库，运用农业生态系统中广泛使用的DNDC（DeNitrification and DeComposition）模型模拟了不同秸秆还田率下全省未来的土壤有机碳动态变化。结果表明，2017—2053年传统管理（15%）以及秸秆还田30%、50%和90%下水田土壤的年均固碳速率分别为173、302、478和838 kg·hm-2，固碳总量分别为11.56、20.15、31.90和55.95 Tg。从土壤亚类来看，咸酸和盐渍水稻土的年均固碳速率最大，不同秸秆还田率下介于220~920 kg·hm-2·a-1之间；而渗育和潴育水稻土的固碳量最大，不同秸秆还田率下合计介于9.45~45.52 Tg之间，约占研究区总固碳量的81%。从行政区来看，龙岩、泉州两个地级市的固碳速率和总量均最大，不同秸秆还田率下均分别在202~937 kg·hm-2·a-1和1.55~8.34 Tg之间。总体而言，福建省水稻土亚类和行政区在不同秸秆还田率下的固碳潜力差异很大，应有针对性制定“固碳减排”管理措施。
【Objective】Straw returning is generally considered to be an effective way to increase soil "carbon sink" and mitigate climate change. China is rich in straw resources, but the rate of straw returning to the field is less than 20%, which is the main reason for a long-term deficit of carbon pool in farmland soils in China. There are many kinds of straw resources in subtropical region, which also account for about 30% of the total output of the country. Therefore, clarifying the quantitative relationship between the amount of straw returning and soil carbon sink in subtropical areas of China is an important basis for formulating carbon sequestration measures and implementing national strategies such as carbon neutralization.【Method】Paddy soil in Fujian Province, a typical subtropical region in China, was selected as our study area. The spatial database was constructed by the digitization of 1:50, 000 soil map paper data from 84 counties (cities and districts) in Fujian Province during the second soil census in 1982. The soil attribute database is composed of 15, 833 surface samples from the arable land fertility survey conducted by the Ministry of Agriculture and Rural Areas in 2016. ArcGIS software and the PKB method (Pedological Knowledge-Based Method) connect the spatial data and attribute data in a 1:50 000 soil database. Using the latest established 1:50000 soil database and DNDC (DeNitrification and DeComposition) model widely used in the agricultural ecosystem, the future dynamic changes of soil organic carbon under different rates of straw returned in Fujian Province were simulated. 【Result】 Results showed that the average annual carbon sequestration rates can reach 173, 302, 478 and 838 kg·hm-2, and the sequestration of carbon amounts were 11.56, 20.15, 31.90 and 55.95 Tg during the period of 2017-2053 under the treatments of conventional management (15%), straw returning of 30%, 50%, and 90%, respectively. Straw was returned to the field from the perspective of carbon sequestration rate, the average annual carbon sequestration rates of Acid sulfate paddy soils and Salinized paddy soils were the highest, which ranged from 220 to 920 kg·ha-1 under different straw returning rates. In terms of total carbon sequestration, the total carbon sequestration of Percogenic paddy soils and Hydromorphic paddy soils under different straw returning rates accounted for 81% of the total carbon sequestration over the whole province. Considering the administrative areas, the average annual carbon sequestration rate and total amount in Longyan and Quanzhou were relatively large, ranging from 202~937 kg·hm-2and 1.55~8.34 Tg under different straw returning rates, respectively.【Conclusion】In general, the increase in straw returning ratio contributed significantly to the "carbon sink" of paddy soil in Fujian Province, which is worth promoting. However, under different straw returning rates, due to the influence of soil properties, climate, fertilization and other factors, the contribution of different soil subtypes and administrative regions in Fujian Province to carbon sequestration varies greatly. In the future, it is necessary to formulate reasonable management measures for carbon sequestration and emission reduction for different soil types and prefecture-level cities.
罗玉叶,邱龙霞,龙军,陈瀚阅,毋亭,李晶,邢世和,张黎明.不同秸秆还田率情境下的亚热带水田土壤的“碳汇”贡献模拟研究[J].土壤学报,2023,60(5):1442-1455. DOI:10.11766/trxb202112280700 LUO Yuye, QIU Longxia, LONG Jun, CHEN Hanyue, WU Ting, LI Jing, XING Shihe, ZHANG Liming. Research on the Carbon Sink Contribution of Subtropical Paddy Field Soil Under Different Straw Return Rates[J]. Acta Pedologica Sinica,2023,60(5):1442-1455.复制