未来30年川东平行岭谷区县域农田SOC动态模拟

Dynamic simulation of farmland SOC in parallel ridge valley area in eastern Sichuan in the next 30 years

  • 摘要: 以位于川东平行岭谷的典型县——垫江县为研究对象,探讨在特定气候模式下未来30 a研究区农田土壤有机碳(SOC)及其动态变化,为研究区未来耕地可持续利用与管理提供数据支持和科学依据。利用生物地球化学模型DNDC,选取IPCC AR4报告中的BCCR_BCM 2.0的B1模式,在基于研究区土壤性质和农业管理制度等建立的GIS区域数据库的支持下,模拟研究区2011—2041年SOC动态变化。结果表明:1)DNDC模型能够较好地模拟特定气候条件下SOC及其动态变化,模拟值和观测值的相关系数r为0.981,达到0.01水平下的极显著相关关系;模拟值和观测值的RMSE值为16%,模拟结果较好。2)未来30 a研究区农田0~20 cm土层SOC密度和储量均呈显著增加态势,单位面积碳增量2 637.07~8 091.55 kg(C)·hm-2,增幅为10%~34%,新增固碳量2.7×105~8.3×105 t,年均增速87.9~269.7 kg(C)·hm-2·a-1。3)未来30 a川东平行区县域农田土壤总体呈持续碳增汇状态,研究区固碳、丢碳以及相对平衡三者间的差异将逐渐凸显。

     

    Abstract: The relationship between greenhouse gas emission reduction and soil carbon sequestration has become the focus of global climate change research amidst the worsening global climate change. As a core interface of terrestrial ecosystem, farmland soils have a huge potential to sequester carbon. Exploring the response and feedback of the dynamic balance of farmland soil organic carbon (SOC) to global climate change is significant in understanding the relationship between global carbon cycle and agricultural ecosystems. Dianjiang County is a typical representation of parallel ridge valley area in eastern Sichuan. It is an important grain and oil producing area in Chongqing. In the process of transformation from traditional to modern agriculture, the area has been faced with double pressures of food security and increasing farmland SOC. Therefore in this region, it is very important to study farmland SOC and its dynamic change using specific climate model in the next 30 years. It provides data support and scientific basis for sustainable utilization and management of future cultivated lands in the study area. Supported by GIS regional database established for soil properties and agricultural management system, this study simulated the dynamic change in SOC in the study area for the period 2011-2041 using the biogeochemical model DNDC. The study also used the B1 climate model within BCCR_BCM 2.0 in the IPCC AR4 report. The results showed that:1) The DNDC model fairly simulated farmland SOC and dynamic change under specific climate conditions. The correlation coefficient between the simulated and measured values was 0.981, which was significant at the 0.01 confidence level. The RMSE value of the simulated and measured values was 16%, indicating better simulated results. 2) The SOC density and storage in the 0-20 cm soil layer in the study area significantly increased for the next 30 years. The increase in carbon per unit area was 2 637.07-8 091.55 kg(C)·hm-2 or 10%-34%, that in carbon sequestration was 2.7×105-8.3×105 t, and that in average increase rate was 87.9-269.7 kg(C)·hm-2·a-1. 3) For the next 30 years, the farmland soil in parallel ridge valley area in eastern Sichuan was generally under continuous carbon sink. In the study area, the differences among carbon sink, carbon loss and carbon relative balance gradually increased for the next 30 years.

     

/

返回文章
返回