低分子量有机酸对亚热带地区典型土壤磷吸附的影响  

Influence of Organic Acids with Low Molecular Weight on Phosphorus Sorption by Typical Soils in Subtropical Regions

作　　者：张苗苗[1] 黄鑫星 罗沛 刘锋[1] 宫殿林 肖润林[1] ZHANG Miao-miao;HUANG Xin-xing;LUO Pei;LIU Feng;GONG Dian-lin;XIAO Run-lin(Institute of Subtropical Agriculture,Chinese Academy of Sciences,Key Laboratory of Agro-Ecological Processes in Subtropical Region,Changsha Research Station for Agricultural and Environmental Monitoring,Changsha 410125,PRC;Hangzhou Cigarette Factory,China Tobacco Zhejiang Industrial Co.,Ltd.,Hangzhou 310024,PRC)

机构地区：[1]中国科学院亚热带农业生态研究所,亚热带农业生态过程重点实验室,长沙农业环境观测研究站,湖南长沙410125 [2]浙江中烟工业有限责任公司杭州卷烟厂,浙江杭州310024

出　　处：《湖南农业科学》2024年第2期23-30,共8页Hunan Agricultural Sciences

基　　金：国家自然科学基金(41701566和42177296);湖南省自然科学基金(2023JJ30615)。

摘　　要：为探索低分子量有机酸对亚热带地区典型土壤磷吸附的影响,采用批处理法研究了柠檬酸和草酸对旱地土、水稻土磷素吸附特征的作用,重点探讨了不同浓度有机酸和柠檬酸钠、有机酸加入顺序等对土壤磷吸附的影响。结果表明:柠檬酸和草酸显著降低了土壤磷吸附动力学的颗粒内扩散模型拟合度,减弱了磷素在土壤颗粒内部扩散过程。Langmuir和Freundlich方程对有机酸存在下土壤磷吸附等温数据均有较好的拟合效果(R2=0.863~0.996)。有机酸降低了土壤磷素最大理论吸附量。土壤磷吸附量与有机酸浓度呈指数函数关系,0.1~5 mmol/L有机酸对土壤磷吸附的影响最大。有机酸浓度小于1 mmol/L时,柠檬酸对土壤磷素吸附的抑制程度大于草酸;而当浓度大于5 mmol/L时,草酸的抑制程度更大。在相同浓度时,0.1~5 mmol/L的柠檬酸钠比柠檬酸对土壤磷吸附能力抑制程度更大,先加入有机酸进一步降低了土壤对磷素吸附量,说明阴离子竞争吸附是低浓度柠檬酸降低土壤磷吸附能力的主要原因,而柠檬酸浓度为5~50 mmol/L时,有机酸与土壤铁铝等金属离子的络合作用占主导。In order to explore the influence of organic acids with low molecular weight on phosphorus sorption by typical soils in subtropical regions,the effects of citric acid and oxalic acid on phosphorus sorption by upland and paddy soils were studied by using batch experiments.The influence of different concentrations of organic acids and sodium citrate and the addition order of organic acids on phosphorus sorption by soil were discussed.The results show that citric acid and oxalic acid significantly reduce the fitting degree of the intraparticle diffusion model of phosphorus sorption kinetics of soil and weaken the phosphorus diffusion process in soil particles.The Langmuir and Freundlich equations have a good fitting effect on isothermal data of phosphorus sorption by soil in the presence of organic acids(R~2=0.863–0.996).Organic acids reduce the maximum theoretical amount of phosphorus sorption by soil.The amount of phosphorus sorption by soil is exponentially related to the concentration of organic acids,and organic acids of 0.1–5 mmol/L have the greatest influence on phosphorus adsorption by soil.When the concentration of organic acids is less than 1 mmol/L,the inhibition degree of citric acid on phosphorus adsorption by soil is greater than that of oxalic acid.When the concentration is greater than 5mmol/L,the inhibition degree of oxalic acid is greater.At the same concentration,adding sodium citrate of 0.1–5 mmol/L has greater inhibition on phosphorus adsorption by soil than citric acid,and the early addition of organic acids further reduces phosphorus sorption by soil,indicating that the competitive sorption of anions is the main reason for the reduction of phosphorus sorption by soil caused by citric acid at a low concentration.The complexation of organic acids with metal ions such as iron and aluminum in soil is dominant at a concentration of citric acid of 5–50 mmol/L.

关 键 词：磷吸附 土壤 柠檬酸 草酸 低分子量有机酸 

分 类 号：S153.612[农业科学—土壤学]