近30 a玛纳斯县北部土壤有机碳储量变化

研究玛纳斯县北部土壤有机碳时空变异特征,可以为当地土壤肥力管理提供理论依据。本文采用地统计学和GIS相结合的方法,研究了玛纳斯县北部地区1980-2011年间土壤有机碳的时空变异特征。研究结果表明:研究区32a来1m深土体土壤有机碳密度和储量呈现增加的趋势,分别较1980年二次土壤普查时增加1.81kg/m2和7.7×106kg;2011年0～20、>20～60和>60～100cm土壤有机碳质量分数平均值为5.74、4.44和2.17g/kg;0～20cm和>20～60cm土壤有机碳含量符合正态分布特征,相应土壤有机碳变异函数理论模型分别符合指数和球状模型;0～20cm土壤有机碳和>20～60cm土壤有机碳均具有中等程度的空间变异性,土壤有机碳的空间分布受土壤母质、地形等结构因素和耕作、施肥等随机因素的共同影响并呈现出南部和东北部高,中部地区偏低的分布特征;>60～100cm土壤有机碳呈现出南部高北部低的空间分布特征。本文获取了玛纳斯县北部地区土壤有机碳时空变异特征,该结果对研究区域土壤肥力管理具有重要意义。

Change of soil organic carbon reserve in northern Manasi county in last 30 years

The temporal and spatial variations of the soil organic carbon(SOC) were studied in order to provide a theoretical basis for the soil fertility management in the northern Manasi county.With the geostatistics and geographic information system(GIS) methods,the temporal and spatial variations of SOC content in the northern Manasi county in last 30 years were investigated.The results indicated that SOC density and reserve presented a rising tendency,which increased 1.81 kg/m 2 and 7.7 ×10 6 kg compared with that of the Second General Survey of Soil in 1980s,respectively.The average values of SOC in 2011 year were 5.74、4.44 and 2.17 g/kg,respectively,for 0-20,>20-60 and >60-100 cm soil layers.Results show that SOC at the 0-20 and >20-60 cm soil layers were normally distributed after excluding the outliers.By experimental semivariograms analysis,SOC were best fitted to exponential and spherical models at 0-20 and >20-60 cm soil layers,respectively.SOC had a moderate spatial variability at 0-20 and >20-60 cm soil layers.The maps of SOC were interpolated using the method of ordinary Kriging.Due to the joint influence of the structural factors such as soil parent material,topography and random factors such as fertilization,crop system etc,the SOC contents at 0-20 and >20-60 cm soil layers had the spatial distributions with a high content in the south and northeast regions and a low content in the central region.The SOC content at 60-100 cm soil layer had a spatial distribution with a high content in the south region and a low content in the north region.The results of temporal and spatial variations of the SOC were of great significance for the soil fertilizer management of the North part of Manasi county.