川西亚高山/高山典型土壤类型有机碳、氮、磷含量及其生态化学计量特征

论文通过研究川西亚高山/高山生态系统不同海拔分布典型土壤类型SOC、TN、TP及其生态化学计量学特征,对比《四川土壤》1985年调查成果,评价我国川西亚高山/高山典型土壤恢复状况。测定亚高山草甸土、草甸土、暗棕壤、棕壤、黄棕壤、褐土的腐殖质层、淀积层、母质层土壤SOC、TN、TP含量,计算生态化学计量值。结果表明：土壤SOC含量表现为亚高山草甸土>草甸土>暗棕壤>褐土>黄棕壤>棕壤,TN含量表现为亚高山草甸土>草甸土>暗棕壤>褐土>黄棕壤>棕壤,TP含量表现为暗棕壤>亚高山草甸土>草甸土>棕壤>褐土>黄棕壤;暗棕壤、棕壤基本表现为SOC、TN、TP含量随土层加深递减;依据第二次全国土壤普查分级标准,研究区土壤有机质呈很丰富水平,TN呈丰富水平,TP呈缺乏水平。土壤SOC、TN和TP水平分布从南向北呈先增加后减少。化学计量比特征：土壤碳氮比表现为草甸土>褐土>黄棕壤>亚高山草甸土>暗棕壤>棕壤,土壤碳磷比表现为草甸土>黄棕壤>褐土>暗棕壤>亚高山草甸土>棕壤,土壤氮磷比表现为草甸土>暗棕壤>黄棕壤>褐土>亚高山草甸土>棕壤,TP是主要限制因子。对比1985年调查结果,经过近30 a的恢复,亚高山草甸土、草甸土、黄棕壤、褐土土壤SOC含量呈增加趋势,棕壤SOC含量下降幅度最大,2015年仅为1985年的31.06%;土壤TN变化不大;TP含量呈下降趋势,变化幅度在56.41%~87.85%之间。

Content and Ecological Stoichiometry Characteristics of Organic Carbon,Nitrogen and Phosphorus of Typical Soils in Sub-alpine/Alpine Mountain of Western Sichuan

In this paper, organic carbon, total nitrogen, total phosphorus contents and ecological stoichiometry characteristics of typical soil types at different elevations of sub-alpine /alpine mountain of western Sichuan were studied and compared with the results of survey made in 1985. The content and ecological chemistry variables in humus horizon, illuvial horizon and parent materials horizon of various soil types (subalpine mountain meadow soil, meadow soil, dark brown soil, brown soil, yellow brown soil, cinnamon soil) were measured and calculated. The results show that in terms of soil organic carbon, the soils are sorted in following order: subalpine mountain meadow soil>meadow soil>dark brown soil>cinnamon soil>yellow brown soil>brown soil; in terms of total nitrogen content, the soils are sorted in following order: dark brown soil>subalpine mountain meadow soil>meadow soil>brown soil>cinnamon soil>yellow brown soil; in terms of total phosphorus contents, the soils are sorted in following order: subalpine mountain meadow soil>brown soil>meadow soil>dark brown soil>cinnamon soil>yellow brown soil; and the contents of dark brown soil, brown soil decrease with the increasing of the depth. According to the classification standard of Second National Soil Survey, the survey region is highly rich in soil organic carbon, rich in total nitrogen, and lack of total phosphorus, and such three elements firstly increase and then decrease from south to north. The ecological stoichiometry characteristics, soil carbon-nitrogen ratio: meadow soil>cinnamon soil>yellow brown soil>subalpine mountain meadow soil>dark brown soil>brown soil, carbon-phosphorus ratio: meadow soil>yellow brown soil>cinnamon soil>dark brown soil>subalpine mountain meadow soil>brown soil, nitrogen-phosphorus ratio: meadow soil>dark brown soil>yellow brown soil>cinnamon soil >subalpine mountain meadow soil >brown soil,, and total phosphorus content is the limiting factor of soil quality. Compared with the result of the survey in 1985, the organic carbon content in subalpine mountain meadow soil, meadow soil, yellow brown soil and cinnamon soil increased and the organic carbon content in brown soil decreased significantly (the content in 2015 was 31.06% of that in 1985) during the past three decades; total nitrogen content had slight change; total phosphorus content decreased with range between 56.41% - 87.85%.