土壤电导率对土壤含盐量及施肥浓度的响应试验研究  

Experimental study on the response of soil conductivity to soil salt content and fertilizer concentration

作　　者：张一清 王文娥[1] 胡笑涛[1] 王旭庆 王世隆 ZHANG Yiqing;WANG Wen'e;HU Xiaotao;WANG Xuqing;WANG Shilong(Key Laboratory of Agricultural Soil and Water Engineering in Arid Areas of Ministry of Education,Northwest A&F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学、旱区农业水土工程教育部重点实验室,陕西杨凌712100

出　　处：《中国农业大学学报》2023年第3期176-187,共12页Journal of China Agricultural University

基　　金：国家自然科学基金项目(52079113);陕西省自然科学基金项目(2020JM-166)。

摘　　要：为探索土壤含盐量及施肥量对土壤溶液养分供给的影响,以土壤电导率为研究对象,通过设置3种土壤含盐量、4种设计含水率和4种浓度K_(2)SO_(4)溶液共48种工况下土柱试验(S1~S48),采用5TE传感器连续观测土壤含水量和电导率,分析土壤含盐量、施肥浓度对不同含水率时土壤电导率的影响。结果表明:土壤含盐量较高时,高盐度会影响介电常数ε和含水率θ的关系,造成5TE测得含水率偏高;定义盐度指数为土壤电导率σb随体积含水率θ的变化率,可通过盐度指数X′s修正含水率θ,修正后含水率的精度可达±2%;当土壤被电导率为0 mS/cm的溶液润湿时(未施肥),初始盐度指数X′si并不为零,这说明土壤自身会溶解出来一部分养分,且当土壤养分充足时,不可忽略土壤自身本底值对电导率的贡献。因此,在施肥过程中,应充分考虑土壤的含盐量差异,进行合理施肥,避免因盲目施肥造成土壤养分利用率低下以及肥料的浪费。The aim of this study was to explore the effect of soil salt content and fertilizer application rate on the nutrient supply of soil solution.Taking soil conductivity as the research object,this study conducted soil column tests under 48 working conditions(S1 to S48)of 3 soil salt content,4 designed water contents and 4 concentrations of K_(2)SO_(4)solution.The 5TE sensor was used to continuously observe the soil water content and conductivity.The effects of soil salt content and fertilizer concentration on soil conductivity at different water contents were analyzed.The results showed that:When the soil salt content was high,the high salinity affected the relationship between the dielectric constantεand the water content θ,resulting in a high water content measured by 5TE.The salinity index was defined as the change rate of soil conductivityσbwith volumetric water contentθ.The water content θ was corrected by the salinity index X′s,and the accuracy of the corrected water content reached ±2%.When the soil was wetted by a solution with a conductivity of 0 mS/cm(not fertilized),the initial salinity index X′siwas not zero indicating that the soil itself would dissolve some nutrients.When the soil nutrients were sufficient,the contribution of the soil’s own background value to the conductivity could not be ignored.Therefore,in the process of fertilization,full consideration of the difference in soil salt content and rational fertilize soil should be conducted to avoid the low utilization rate of soil nutrients and waste of fertilizer caused by blind fertilization.

关 键 词：土壤电导率 盐度指数 体积含水率 润湿溶液电导率 土壤含盐量 施肥浓度 

分 类 号：S152.7[农业科学—土壤学] S153[农业科学—农业基础科学]