甘肃白龙江流域土壤有机碳与全氮储量的空间格局特征

Spatial Distribution Characteristics of the Storages of Soil Organic Carbon and Total Nitrogen in the Bailongjiang Watershed of Gansu

土壤有机碳与全氮储量的空间格局特征不仅可为土壤质量管理提供科学依据,也可为流域生态系统管理及人类活动管控提供参考。基于GIS软件平台,统计分析了甘肃白龙江流域土壤有机碳与全氮储量及碳氮比的空间格局特征,并探讨了海拔、坡度、坡向和植被覆被类型对土壤有机碳、全氮储量空间分布的影响。结果表明:甘肃白龙江流域平均土壤有机碳、全氮储量分别约为87.94×10~3 kg hm^(-2)和7.02×10~3 kg hm^(-2),两者在空间上均呈现西北向东南逐级递减的态势;流域土壤有机碳储量随海拔和坡度的增加呈先增后减的变化趋势,其高值区主要分布在2053~3779 m和20°~35°区段;土壤全氮储量随海拔上升而增加,随坡度增加呈先减再增后减的趋势,其高值区主要分布在20°~35°区段;坡向对流域土壤有机碳、全氮储量空间分布的影响相对较小;常绿针叶林、常绿阔叶林和落叶针叶林是流域土壤有机碳、全氮储量的高值区,低值区集中在耕地。

The research on spatial pattern of the storages of soil organic carbon and total nitrogen not only provides a scientific basis for soil quality management, but also provides a reference for ecosystem management and control of human activities. In this paper, based on the GIS software platform, we analyzed the spatial distribution characteristics of the storages of soil organic carbon and total nitrogen and discussed the influences of elevation, slope, aspect and vegetation type on them in the Bailongjiang Watershed of Gansu in 2014. Average storages of soil organic carbon and total nitrogen were about 87.94 × 10^3 kg hm^-2 and 7.02 × 10^3 kg hm^-2 and both showed decreasing trends from the northwest to the southeast in the Bailongjiang Watershed of Gansu. With the rising of elevation and slope, soil organic carbon storage increased firstly and then decreased and was the highest at the elevation of 2053 m to 3779 m and at the slope of 20° to 35°. The higher elevation was, the more soil total nitrogen storage was. Meanwhile, it firstly decreased, and then increased, and last decreased with the rise of slope. Its higher value was mainly distributed at the slope of 20° to 35°. The influence of aspect on the spatial distribution of the storages of soil organic carbon and total nitrogen was relatively little. Evergreen coniferous forest, evergreen broad-leaved forest and deciduous coniferous forest had higher storages of soil organic carbon and total nitrogen, and lower storages were mainly concentrated on arable land.