蒙古高原中北部土壤有机质空间分布研究

The spatial distribution of soil organic matter on north-central Mongolian Plateau

土壤有机质是土壤质量或肥力的重要表征要素,其在区域内的空间分布状况与当地的生态环境状况具有一定的相关性。蒙古高原处于干旱半干旱气候区,常年遭受风蚀等灾害影响,再加上人为活动的破坏,土壤养分流失严重,生态状况堪忧。本研究即是以蒙古高原中北部为研究区,对该地区土壤有机质做空间化扩展研究,通过选取与有机质相关的环境要素,包括高程、年均气温、年均降雨量以及归一化植被指数,建立地理加权回归插值模型,获取了土壤有机质的空间分布状况。结果显示,研究区土壤有机质含量分布具有明显的地区差异,北部山地区域有机质含量普遍较高,最高约为43.35%,而在南部戈壁和荒漠区有机质含量相当低,接近于0,气候和地形是影响其空间分布差异的主要因素。

Soil organic matter（SOM）is an important representation of soil quality or soil fertility,and its spatial distribution characteristic correlates with the ecological environment regionally. The Mongolia Plateau is in an arid and semi-arid climate zone and disturbed by wind erosion and other natural disasters perennially coupled with destruction of human activities,soil nutrient loss is serious and the local ecologic system is vulnerable. This study took the middle and northern area of the Mongolian Plateau as a study area. Elevation,mean annual temperatures,mean annual precipitation and NDVI were selected as environmental indicators,and correlated with SOM content of sample points to construct a geographically weighted regression model to gain the spatial distribution of SOM. Land cover types were also used in combination with interpolation results to analyze the spatial distribution characteristics of SOM and influence on SOM content.We found that the content of SOM in the study area had regional differences,content in the northern mountainous areas was generally higher than 40%,while in the southern desert area the content was close to zero. Landform and climate were the main factors affecting spatial distribution differences. In the north,there were more mountains covered by forest,bush and grass with plenty of moisture from the Arctic Ocean,beneficial for the accumulation of SOM. In the south it was always desertification area and the soil was barren with rare vegetation,bad for the accumulation of SOM.