陕西省农田土壤有机质时空变异与驱动因子定量研究

Spatiotemporal Variation and Driving Factors for Cultivated Soil Organic Matter in Shaanxi Province

为揭示土壤有机质(Soil organic matter, SOM)时空变异性与驱动因子响应机制,保障区域耕地可持续利用与粮食安全,应用地理探测器、地统计和重心偏移方法对陕西省SOM含量时空变异格局与驱动因子进行研究。结果表明:整体上,陕西省2017年SOM分布呈南高北低格局,平均含量(质量比)为15.63 g/kg,较2007年提升8.61%;空间上,2017年SOM含量重心整体向西南偏移,陕南向西迁移,关中向东迁移,陕北向西南偏移;2017年SOM含量空间变异主导驱动因子为土壤全氮含量(q为0.74);2007—2017年间,土壤全氮含量、年平均气温、机械总动力对SOM含量空间变异的驱动力提升较大;2007—2017年,自然与人文因素共同驱动SOM含量时空变异,但人类活动对两因素均具有重要影响。

Soil organic matter(SOM) is the leading factor of soil fertility and quality. Revealing the spatiotemporal variation and driving factors of SOM is the basis for studying sustainable use of cultivated land and food security. Geographic detector, geostatistics and center of gravity shift methods were applied to analyze the spatiotemporal variation distribution pattern and identify the driving factors of SOM content in Shaanxi Province. The results showed that the distribution of SOM showed a pattern of high in the south and low in the north in Shaanxi Province in 2017 overall, with an average content of 15.63 g/kg, an increase of 8.61% compared with that of 2007. Spatially, the center of gravity of SOM content shifted southwest, southern Shaanxi shifted westward, Guanzhong shifted eastward, and northern Shaanxi shifted southwest in 2017 compared with that in 2007;STN content(q=0.74) was the leading driving factor of SOM content spatial variation, followed by county administrative division, municipal administrative division, annual precipitation, annual mean temperature, soil subtypes, and soil types, which q values were greater than 0.3 in 2017;during 2007—2017, the driving force of soil total nitrogen(STN) content, annual average temperature and total mechanical power on SOM content variation was increased significantly, q value was increased by 0.39, 0.21 and 0.18, respectively;from 2007 to 2017, natural and human factors jointly drove the spatiotemporal variation of SOM content, but human activities had an important impact on both factors.