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基于对4个取样尺度(10、5、2.5、1.25 m)下亚高山草甸土壤呼吸速率的观测,对不同尺度土壤呼吸的空间变异特征进行了研究,分析了不同尺度土壤全氮、有机碳、碳氮比、全硫、土壤温度和土壤水分对土壤呼吸空间异质性的影响,并对各尺度不同置信水平与估计精度下的必要采样数量进行了计算.结果表明:除1.25 m和2.5 m尺度上土壤温度的空间变异属于弱变异外,土壤呼吸及其相关因子的空间变异均属于中等变异,土壤呼吸和土壤温度的变异系数随着取样尺度的增大而增大,而土壤全氮、有机碳、全硫和土壤水分的变异系数随着取样尺度的增大均有减小的趋势;不同取样尺度,影响土壤呼吸的关键因子不同.在10 m尺度,土壤呼吸与土壤全氮、有机碳呈极显著正相关,与土壤温度呈显著正相关,与土壤全硫、碳氮比和土壤水分相关性不显著;在5 m尺度,与土壤全氮和有机碳呈极显著正相关,与土壤全硫、碳氮比、土壤水分和土壤温度相关性不显著;在2.5 m尺度,与土壤有机碳、全氮和土壤水分呈极显著正相关,与土壤全硫、碳氮比和土壤温度相关性不显著;在1.25 m尺度,与土壤全氮、有机碳和土壤水分呈极显著正相关,与碳氮比呈显著负相关,与土壤温度呈极显著负相关,与土壤全硫相关性不显著.随着取样尺度的减小,土壤水分所起的作用逐渐增大,相关系数从0.27~0.49,土壤温度与土壤呼吸的相关性由显著正相关向极显著负相关变化;4个取样尺度95%置信水平误差在10%和20%内必要采样数量分别为28、21、18、14个和7、5、4、4个,随着取样尺度的减小,必需的采样数量减少.
Based on the observation of soil respiration rate in subalpine meadow at four sampling scales (10, 5, 2.5 and 1.25 m), spatial variability of soil respiration at different scales was studied. The effects of soil total nitrogen, organic carbon , Carbon and nitrogen ratio, total sulfur, soil temperature and soil moisture on the spatial heterogeneity of soil respiration, and calculated the necessary sampling quantities under different confidence levels and estimated accuracy at each scale.The results showed that except 1.25 m and 2.5 The spatial variability of soil temperature at m-scale belongs to the weak variation. The spatial variability of soil respiration and its related factors belong to the medium variation. The coefficient of variation of soil respiration and soil temperature increases with the increase of sampling scale, , And the coefficient of variation of organic carbon, total sulfur and soil moisture all decreased with the increase of sampling scale.The key factors influencing soil respiration were different at different sampling scales.Results of soil respiration and soil total nitrogen, There was a significant positive correlation between soil organic carbon and organic carbon. There was a significant positive correlation between soil organic carbon and soil organic carbon. There was no significant correlation with soil total sulfur, C / N ratio and soil moisture at 5 m scale. There was a significant positive correlation between soil total C, N and soil moisture and soil temperature. At 2.5 m scale, there was a significant positive correlation with soil organic carbon, total nitrogen and soil moisture, There was no significant correlation between C and N and soil temperature. At the scale of 1.25 m, there was a significant positive correlation with soil total N, organic carbon and soil moisture, a significant negative correlation with C and N, and a significant negative correlation with soil temperature. And the correlation with soil total sulfur was not significant.With the decrease of sampling scale, the role of soil moisture gradually increased, the correlation coefficient ranged from 0.27 to 0.49, and the correlation between soil temperature and soil respiration was significantly and significantly negative The necessary sampling numbers of 95% confidence level error in 4 sampling scales are 28, 21, 18, 14 and 7, 5, 4 and 4 respectively in 10% and 20%. As the sampling scale decreases, The number of necessary samples is reduced.