祁连山不同植被类型土壤碳贮量和碳通量

Soil carbon storage and CO_2 flux under different vegetation types in Qilian Mountains

采用野外调查测定、野外定位观测和室内分析相结合的方法，在植被类型变化较大林区，选择邻近相同海拔、坡向和土壤类型的天然林（青海云杉林、祁连圆柏林、高山灌丛林）、人工林（13年生华北落叶松林）、牧坡草地和农田等植被类型土壤为研究对象，研究了祁连山不同植被类型的土壤碳动态。结果表明：天然林、牧坡草地、农田和人工林的土壤有机碳含量分别为59．45～84．7、78．30、13．51和43．25g·kg^-1，平均土壤有机碳密度分别为15．96—19．95、17．74、10．63和15．97kg·m^-2，土壤有机碳平均周转时间分别为27～36、25、23和33a；不同植被类型土壤CO2通量依次为青海云杉林584．03g C·m^-2·a^-1，祁连圆柏林517．63g C·m^-2·a^-1，高山灌丛林601．00g C·m^-2·a^-1，牧坡草地796．89g C·m^-2·a^-1，农田281．75g C·m^-2·a^-1，人工林569．92g C·m^-2·a^-1；同一植被类型中，土壤有机碳含量和土壤碳密度随土壤深度增加而降低，而土壤有机碳周转时间则随深度增加而增大。

Based on field survey, field-orientation observation and laboratory analysis, this paper studied the soil carbon storage and CO2 flux under natural forests （picea crassifolia, Sabina przewalskii, and alpine shrub） , artificial larch forest, rangeland, and cropland at the paired plots with same elevation, slope direction, and soil type in the National Nature Reserves of Qilian Mountains. The results indicated that the soil organic carbon （SOC） content under natural forests, rangeland, cropland and larch plantation was 59： 45-84, 7, 78, 30, !3, 5! and 43.25 g · kg^-1, mean SOC density was 15.96-19.95, 17.74, 10,63 and 15.97 kg · m^-2, and mean SOC turnover time was 27-36, 25,23 and 33 years, and the soil C02 flux under P. crassifolia, S. przewalskii, alpine shrub, rangeland, cropland, and larch plantation was 584. 03, 517.63, 601.00,796.89,281.75 and 569.92 g C·m^-2·a^-1, respectively. Under the same vegetation type, SOC content and density decreased with soil depth inereasing, while SOC turnover time was in adverse.