石羊河下游民勤湖区土壤特性的空间分异研究

Study on Spatial Variations of Soil Properties in Minqin Lake Area of Shiyang River Lower Reaches

通过野外试验和室内分析,对石羊河下游民勤湖区土壤盐分、pH值和养分的空间分异进行了研究。结果表明:土壤电导率和pH值、速效钾含量都是荒漠区最大,绿洲区最小,而碱解氮和速效磷含量则是绿洲区最大,荒漠区最小。垂直方向上,土壤电导率和pH值变化略显复杂。研究区土壤养分表现为"丰氮、富钾、贫磷"的总体特征;在水平和垂直方向上,土壤电导率和氮、磷、钾都属于中等变异,pH值属于弱变异;土壤电导率值除了表层与60 cm土层表现为中等自相关,其余的都呈纯金块效应,说明研究区土壤的电导率值很容易受到随机因素的影响;土壤pH值属于中等或强自相关性,各层的块金值不大,说明pH值主要受自然因素的影响;土壤养分指标中,碱解氮与速效钾属中等或强自相关性,速效磷则表现为纯金块效应,完全受随机因素影响。

Based on field tests and laboratory analyses, spatial variations of soil salt, pH value and nutrients in Minqin Lake area of Shiyang River lower reaches were studied. The results showed that the maximum of soil conductivity, soil pH value and available potassium were located in desert region and the minimum in oasis, while the maximum of available nitrogen and available phosphorus were located in oasis and the minimum in desert. The changes of soil conductivity and soil pH value were slightly complicated from the top to deeper layer. Soil nutrients in the study area were of abundant nitrogen, rich potassium but poor phosphorus; in horizontal and vertical direction, soil conductivity, N, P, and K all showed medium variation, while soil pH value small variation. Only soil conductivity of the top layer and at 60 cm had medium degrees of autocorrelation. Soil conductivity of other layers all showed pure nugget effect, showing it was easily affected by random factors. Soil pH value showed medium or strong autocorrelation. The nugget of pH value was small in each soil layer, meaning it was mainly affected by natural factors, Available nitrogen and potassium showed medium or strong autocorrelation. Available phosphorus showed pure nugget effect, meaning it was affected by random factors.