一种通用型土壤有效元素高效提取方法及应用

A Universal Method for Efficient Extraction of Soil Available Elements and Its Application

Mehlich 3(M3)方法可同时提取土壤中P、K、Ca、Mg、Al、Fe、Zn、Mn、Cu等多种元素的有效态,也同时适用于钙质土、火山灰土、高度风化土等各类土壤。但是由于硝酸铵(NH_(4)NO_(3))为管制化学品,不易获取,应用M3方法测定土壤有效元素含量时受到极大限制。因此,本研究用另一种易获取的惰性电解质NH_(4)Cl替代NH_(4)NO_(3),评价NH_(4)Cl替代NH_(4)NO_(3)的M3法(NH_(4)Cl-M3法)适用性。Pearson相关分析结果表明,用NH_(4)Cl-M3法测得的30种土壤有效P、速效K含量与M3法测定结果呈极显著正相关,其决定系数(R^(2))分别为0.99(P=2.31×10^(-55),n=60)和0.98(P=1.52×10^(-49),n=60)。同时,NH_(4)Cl-M3法和M3法测定的有效Ca、Mg、Al、Fe、Zn、Mn、Cu含量极显著相关,R^(2)值分别为0.98,1.00,0.99,0.96,0.99,0.95和0.94。NH_(4)Cl-M3-P与酸性、中性和碱性土壤的Bray-P和Olsen-P极显著相关,R^(2)分别为0.97和0.91(P=1.42×10^(-15)、1.00×10^(-21),n=20、40)。同时,利用NH_(4)Cl-M3法测定酸性改良土壤有效P含量,发现其得到显著提高。因此,NH_(4)Cl-M3法可作为测定各种土壤,以及改良土壤中有效P、速效K和其他金属元素有效态含量的通用方法。

Mehlich3(M3)method can simultaneously determine the contents of soil available P,K,Ca,Mg,Al,Fe,Zn,Mn and Cu,and is feasible for calcareous,andosol and highly weathered soils.However,it is hard to get NH_(4)NO_(3) used in M3 method due to its explosibility,therefore,it is necessary to find other substances to replace NH_(4)NO_(3).In this paper,M3 method was modified by using indifferent-electrolyte ammonium chloride(NH_(4)Cl)to replace NH_(4)NO_(3)(NH_(4)Cl-M3 method)to determine available elements in 30 topsoils.Pearson correlation analysis showed available P and K contents in the tested 30 topsoils determined by the two methods were significantly correlated,with determination coefficients(R^(2))of 0.99(P=2.31×10^(-55),n=60)and 0.98(P=1.52×10^(-49),n=60),respectively.Meanwhile,significant correlations were also found for available Ca,Mg,Al,Fe,Zn,Mn and Cu contents determined by the two methods,with R^(2) values of 0.98,1.00,0.99,0.96,0.99,0.95 and 0.94,respectively.Bray-P and Olsen-P of the above acid neutral and alkaline topsoils determined by the two methods were also significantly correlated,with R^(2) values of 0.97 and 0.91(P=1.42×10^(-15) and 1.00×10^(-21)),respectively.Soil available P content determined by NH_(4)Cl-M3 method was significantly promoted than M3 method.Therefore,NH_(4)Cl-M3 method can be an alternative method to determine available P,K and other elements in calcareous and highly weathered soils as well as the amended soils.