选取重庆市垫江县为川东平行岭谷的典型区,使用1980第二次土壤普查和2011年实测土壤数据,基于土壤类型,运用通用SOC 密度/ 储量计算法和逐步回归分析,对研究区19802011年020 cm 农田SOC 动态和动因进行分析,结果表明:(1)19802011年农田020 cm 土层SOC 密度/ 储量总体表现为略有增加态势,单位面积碳增量2307.63 kg C/ hm~2,碳增汇235945.83 t,增幅为10.74%,年均增长速率为72.11 kg C hm~(-2)a~(-1);(2)丢碳、固碳和相对平衡面积比37.61颐49.03颐13.36,总体呈西部、西北部高于南部、东南部,更高于东北部和西南部的格局;(3)宏观上19802011年农田020 cm 土层SOC 密度/ 储量变化与土壤类型的分布及利用有很大关系,尤其是黄壤和紫色土在相异的质地本底和不同的扰动下,展现出相反的碳汇/ 源状态;(4)微观上SOC 密度年均变化速率影响最大的因素是SOC 密度初始值>全N 密度>C/ N 比,且全N 密度和C/ N 比拥有正向影响,SOC 密度初始值则相反;由结果为川东平行岭谷区借助施加适当投入和合适的耕作与管理实践,有效管理农田表层SOC 库提供科学依据。
英文摘要:
Global warming and corresponding serious ecological and environmental problems induced by the rising CO_2 concentrations have attracted worldwide attentions. And they have become the focus of the international negotiations. As one of the core interface of terrestrial ecosystem, farmland soil in terrestrial ecosystems is the most intense part affected by human frequent disturbance. Management agricultural SOC is internationally recognized as one of the important strategies for mitigating or adapting global warming. Paralleled ridge valley of East Sichuan is typically representative of the concentrated distribution area of farmland around the Sichuan basin. It always plays an important role in the granary of East Sichuan. Recently, the production and management investment and frequent tillage disturbance in order to pursuit food security drove the opposite direction change of farmland SOC. Hence, it was very important to carry out the research on SOC dynamics. And, the farmland use of this region would be promoted to the strategic height responding to global change and food security at regional level. Taking Dianjiang County of Chongqing City is a typical area of East Sichuan parallel ridge valley, this paper analyzed the dynamics of farmland SOC of 020 cm soil layer and their driving factors during 19802011 by the soil type method, international general SOC density/ storage calculation method and Stepwise Regression Analysis, using the second soil survey data in 1980 and the measured data in 2011. The results showed:(1)Farmland SOC density/ storage of 020 cm soil layer during 19802011 in the study area overall presented slightly increased trend. Carbon increment per unit area reached to 2307.63 kg C hm~(-2). Total content of carbon sink enhancement was 235945.83 t, with the increasing range of 10.74% and the average annual growth rate of 72.11 kg C hm~(-2) a~(-1).(2)The proportion of carbon sink, loss and relative balance area to the total area of this study area was 37.61:49.03:13.36. In general, the spatial patterns of farmland SOC sink showed that west and northwest part is higher than that south and southeast, and more than that northeast and southwest.(3)At macro level, the changes of farmland SOC density/ storage was pronounced relationship to the distributions of soil type and their utilization practices. Especially, yellow soil and purple soil under different texture and different perturbations, showed the opposite carbon sink/ source state.(4)At microcosmic level, the rank of factors obviously influencing SOC density average annual change rate was SOC density > N >C/ N. Moreover, total N density and C/ N ratio have positive effects on SOC density average annual change rate, the effects of SOC density initial value were negative function.(5)Results of this paper could provide scientific proofs for the effective management of farmland surface SOC carbon pool in the parallel ridge and valley area of East Sichuan, depending on appropriate inputs and suitable cultivation and management practices.