东北黑土区全新世农业转型特征及环境效应

准确评估东亚全新世农业活动的环境效应，是区域人地系统研究的核心议题之一，也是尚未解决的一大难题。利用可靠、相对连续的全新世农业活动记录来研究区域农业转型特征及环境效应，是探索农业活动如何和在多大程度上影响区域环境的有效途径之一。对此，本项目以正在耕作的土壤为参考，以东北不同农业活动区的全新世黑土剖面为研究对象，将对剖面样品进行土壤有机碳组分分离与碳含量、碳氮同位素和14C测年分析以及序列焊接，以重建研究区全新世农业活动的强度序列与环境演化历史，结合东北不同农作物的碳氮同位素组成以识别东北黑土区全新世农业转型特征；与此同时，通过区域全新世农业转型特征与环境背景的对比，以及本研究结果与区域集成记录的对比，试图评估全新世农业转型对研究区生态环境的可能影响，从而为黑土区实施保护性耕作和防范黑风暴生态灾难提供科学依据。

Accurately assessing environmental effects of Holocene agricultural activities in East Asia has been an important issue and an unsolved problem in study of regional man-earth system. Fortunately, based on reliable and relatively-continuous records of the Holocene agricultural activity, research on characteristics and environmental effects of the agricultural regime change offers an effective way to explore how and to what extent agricultural activities affect the regional environment. Thus, we firstly plan to select soil samples from typical Holocene Mollisol profiles and their adjacent plough layer in the agricultural areas of Northeast China, to reconstruct the intensity sequence of Holocene agricultural activities and the history of Holocene environmental evolution based on works of 14C dating and multi-proxies analyses. The multi-proxies analysis will be focused on the carbon content as well as the δ13C and δ15N of different components of organic matter. Meanwhile, the δ13C and δ15N of different crops in the Northeast China will be analyzed in order to provide evidence for further identifying the characteristics of the Holocene agricultural regime change in the Mollisol region of Northeast China. In addition, we will attempt to evaluate possible impacts of the Holocene agricultural regime change on the ecological environments in the study region, based on our new data and a detailed regional compilation of climate change and human activity in Northeast China. It is anticipated that this work will make a substantial contribution to promoting the farmers' adoption of conservation tillage and to maintaining a state of high alert against the "Dust Bowl" drought in the Mollisol region.