吸管法和激光法测定紫色土机械组成对比研究  

Comparative Study on Mechanical Composition of Purple Soil Determined by Pipette Method and Laser Diffraction Method

作　　者：王风香 蒙薪赟 慈恩[1,2] 刘彬 高佳佳 唐江 WANG Fengxiang;MENG Xinyun;CI En;LIU Bin;GAO Jiajia;TANG Jiang(College of Resources and Environment,Southwest University,Chongqing 400715,China;Engineering Research Center of Agricultural Non-Point Source Pollution Control in Three Gorges Reservoir Region,Chongqing 400715,China;Sinochem International Crop Care Company Limited,Shanghai 200126,China)

机构地区：[1]西南大学资源环境学院,重庆400715 [2]三峡库区农业面源污染控制工程技术研究中心,重庆400715 [3]中化作物保护品有限公司,上海200126

出　　处：《西南大学学报（自然科学版）》2024年第9期164-172,共9页Journal of Southwest University(Natural Science Edition)

基　　金：国家自然科学基金项目(41977002)。

摘　　要：吸管法是测定土壤机械组成的经典方法,激光法是测定土壤机械组成的简便方法.为探究两者在紫色土机械组成测定上的差异以及两者之间的联系,分别采用两种方法测定145个紫色土样品的机械组成,并建立线性方程、随机森林回归(Random Forest Regression,RFR)模型和支持向量回归(Support Vactor Regression,SVR)模型进行比较分析.结果表明:(1)相较于吸管法,激光法所测紫色土黏粒含量和粉粒含量均偏高,所测砂粒含量则偏低;(2)随着土壤砾石含量的增加,两种方法所测的相同粒级含量差值逐渐增大,且差值从大到小依次为:砂粒、粉粒、黏粒;(3)相比于pH>7.5的紫色土,两种方法所测的相同粒级含量差值明显大于pH≤7.5的紫色土,且差值从大到小依次为:砂粒、粉粒、黏粒.总体来看,紫色土的砾石含量是影响两种方法所测机械组成关联效果的一个关键因素,对于砾石含量≤5%的紫色土,两种方法的测定结果有很好的关联性,可采用激光法替代吸管法,但测定结果需要校正,建议选用拟合效果较好的RFR或SVR模型进行校正.The pipette method is a classical technique for determining the mechanical composition of soil,while laser diffraction method is a simplified approach.In order to investigate the disparities in mechanical composition between purple soils and their relationship,both methods were employed to analyze 145 samples.Linear equations,random forest regression(RFR)models,and support vector regression machines(SVR)were established for comparative analysis.The findings indicate that:(1)Compared to the pipette method,the laser diffraction method yielded higher measurements of clay and silt content in purple soils,but lower measurements of sand content.(2)As gravel content increased in soil samples,differences between the two methods gradually became more pronounced for each grain size category,with sand exhibiting the greatest disparity followed by silt and clay.(3)In comparison to purple soil with a pH≤7.5,the difference in particle size measured by the two methods was significantly greater for purple soil with a pH>7.5,and the difference followed the order of:sand,powder,clay.The gravel content of purple soil was generally considered as a key factor affecting the correlation between particle size distribution measurements obtained from both methods.When the gravel content was≤5%,measurement results of two methods had good correlation,and laser diffraction method could be used to replace the pipette method.However,calibration of measurement results is necessary when using laser diffraction method,and it is recommended to use RFR or SVR model for calibration due to their better fitting effect.

关 键 词：紫色土 机械组成 激光法 吸管法 

分 类 号：S152.3[农业科学—土壤学]