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针对河西走廊临泽绿洲边缘区域的新垦沙地农田,采用传统统计学和地统计学相结合的方法研究田块尺度的土壤有机碳时空变异特征。结果表明:(1)在本研究的空间尺度内,土壤有机碳含量在2.66～6.90g.kg-1范围之间变化,平均值为4.45g.kg-1,变异系数为24.5%;其空间分布呈明显的斑块状,最佳的变异函数理论模型为指数模型,其块金值和基台值分别为0.13和1.28,偏基台值和基台值的比值及变程分别为0.90及18.24m;土壤有机碳空间分布与全氮、碱解氮、速效磷、速效钾含量及电导率显著正相关(p<0.01),与pH值显著负相关(p<0.05)。(2)在本研究的监测时间尺度内(2004—2010年),土壤有机碳年平均值在3.81～4.71g.kg-1幅度内变化,变异系数为6.8%,无明显的变化趋势;土壤有机碳含量年际间变化与播种量显著正相关,与作物产量显著负相关,而与施氮量、灌溉量和地上部生物量相关不显著。综上所述,新垦沙地农田土壤有机碳含量较区域水平低,其田块尺度的空间异质性是由成土母质、地形等区域因素作用的结果,而对农田管理影响下的新垦沙地农田土壤有机碳含量演变规律的研究需建立在更长时间尺度的土壤监测数据基础上。
Aiming at the newly reclaimed sandy farmlands in the marginal area of Linze Oasis in Hexi Corridor, the temporal and spatial variation characteristics of soil organic carbon at field scale were studied by the combination of traditional statistics and geo-statistics. The results showed that: (1) Within the spatial scale of this study, the content of soil organic carbon varied from 2.66 to 6.90 g · kg-1 with an average value of 4.45 g · kg-1 with a coefficient of variation of 24.5% The distribution of the distribution is obvious plaque, the best theoretical model of the variation function is an exponential model, the value of the block gold and abutment are 0.13 and 1.28 respectively, the ratio of the abutment value to the abutment value and the change range are 0.90 and 18.24 m. The spatial distribution of SOC was significantly and positively correlated with total N, available N, available P, available K and electrical conductivity (p <0.01), and negatively correlated with pH (p <0.05). (2) In the monitoring time scale of this study (2004-2010), the annual average value of soil organic carbon changed within the range of 3.81 ~ 4.71g.kg-1 with a coefficient of variation of 6.8%, with no obvious change trend. Soil The interannual variation of organic carbon content was significantly and positively correlated with sowing rate, significantly negatively correlated with crop yield, but not significantly with nitrogen application rate, irrigation amount and aboveground biomass. In summary, the content of soil organic carbon in newly reclaimed sandy farmland is lower than that in the region, and the spatial heterogeneity of the field scale is the result of the regional factors such as parent material and topography. However, under the influence of farmland management, The evolution of soil organic carbon content in sandy farmland should be based on soil monitoring data at longer time scales.