土壤颗粒悬液搅拌对土壤质地分析的影响

Effects of Stirring Soil Particle Suspension on Soil Texture Analysis

[目的]探究土壤颗粒悬液搅拌对土壤质地分析的影响,为实验室准确测定土壤机械组成提供可行的参考与指导。[方法]采用比重法测定土壤机械组成,在搅拌不同行程、搅拌不同次数、悬液静置不同时间后搅拌、不同测定时点搅拌的多种条件下所测结果进行比较分析。[结果]搅拌行程、搅拌次数、悬液静置后搅拌对黏粒含量测定无影响,对粉砂粒和砂粒含量测定均有影响。搅棒从液面下行至沉降筒底搅拌,有利于颗粒充分运动及均匀分布,黏粒、粉砂粒、砂粒含量测定稳定,精密度良好;以氢氧化钠为分散剂的悬液搅拌30次,黏粒、粉砂粒、砂粒含量测定准确,精密度良好;悬液静置的适宜时间大于1h,搅拌30次所测粉砂粒和砂粒含量的精密度呈下降趋势,搅拌45次所测粉砂粒、砂粒、黏粒含量稳定,精密度良好,与洗后即搅拌30次的测定结果一致。在第2测定时点增加搅拌1min对测定结果无影响。[结论]本试验方法测定结果准确可靠,避免了重复操作,有利于减少误差,适用于多个样品的同时检测。

[Obiective]Effects of stirring soil particle suspension on the analysis of soil texture were researched to provide guidance for the determination of soil mechanical composition accurately.[Methods]The comparison and analysis were carried out under different conditions,such as stirring stroke,stirring number,stirring when soil particle suspension was placed at different time and stirring at different determination time,in the determination of soil mechanical composition by gravimetric method.[Results]The stirring stroke,stirring number and stirring after suspension all had no effect on clay particle content,but had impacts on the silt and sand content.Stirring rod stirred from the liquid level down to the bottom of the precipitation tube was conducive to uniform distribution of particles,determination of the clay,silt and sand content was stable,precision was good.At the condition of the suspension setting time was more than 1 h,measurement of silt and sand content was unstable when it was stirred 30 times.Measurement of silt sand and clay content was stable,precision was good when it was stirred 45 times.The addition of stirring before the second test points had no impact to the results.[Conclusion]The optimized method was helpful to reduce the errorwas accurate and reliable,and suitable for simultaneous detection of multiple samples.