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为明确冻融过程对土壤盐分分布的影响,通过野外采样、室内分析的方法对比分析了奇台县农田冻融前、后土壤含盐量的空间变异性。结果表明:(1)冻融前,表层(0-20 cm)土壤含盐量(0.11%)最低,且基本随着土层深度的增加土壤含盐量逐渐增大。而土壤盐分空间分布的复杂性基本随着土层深度的增加逐渐减小。(2)冻融后,表层(0-20 cm)含盐量(0.14%)变为最高。春季积盐现象明显(主要发生在60 cm深度以上),但尤以表层最为严重(积盐率达30.0%)。模拟秋季灌溉洗盐效果显著,剖面平均(100 cm深度以上)含盐量减少率为8.16%。而且洗盐深度大于100cm。另外,各层土壤含盐量的变异性(中等变异性)未变,但变异系数增大(除40-60cm深度外)。剖面上部土壤盐分的理论模型由指数模型为主均变为高斯模型,且变程增大明显;而底部由高斯模型转为球状模型,且变程变化不大。
In order to clarify the effect of freezing and thawing process on the distribution of soil salinity, spatial variability of soil salinity before and after farmland freeze-thaw in Qitai County was analyzed by field sampling and indoor analysis. The results showed that: (1) Before freezing and thawing, the soil salinity (0.11%) of surface layer (0-20 cm) was the lowest, and the salinity of soil increased with the increase of soil depth. However, the complexity of spatial distribution of soil salinity decreases with the increase of soil depth. (2) After freeze-thaw, the salinity (0.14%) of surface layer (0-20 cm) became the highest. The phenomenon of salt accumulation in spring is obvious (mainly occurs at a depth of 60 cm or more), but the surface layer is the most serious (the salt accumulation rate is 30.0%). Simulating the effect of salt washing in autumn irrigation was significant, and the salinity reduction rate was 8.16% on the average profile (above 100 cm depth). And wash salt depth greater than 100cm. In addition, the soil salt content of the variability (medium variability) did not change, but the coefficient of variation increased (except 40-60cm depth). The theoretical model of soil salinity in the upper part of the profile changed from the exponential model to the Gaussian model, and the variation range increased obviously. The bottom changed from the Gaussian model to the spherical model with little change in the range.