中国几种典型土壤酸碱缓冲容量测定方法的比较

Comparative study on determination methods for acid buffering capacity of several typical soils in China

通过测定土壤酸碱缓冲容量,可以评价土壤抗酸化能力,了解土壤酸化过程,为修复酸化土壤提供依据。以中国部分典型地域的潮土、红壤及太湖地区水稻土为对象,对测定土壤酸碱缓冲容量的酸碱滴定法和培养法进行比较分析,探索适合测定不同土壤类型土壤酸碱缓冲容量的方法。结果显示,使用无CO2蒸馏水、CaCl2(0.01 mol/kg)浸提土壤(土水质量比为1.0∶2.5),运用HCl和NaOH滴定法分析的pH(H2O)、pH(CaCl2)在突变范围内与酸碱加入量呈极显著线性相关(P<0.01;CaCl2浸提的红壤pH除外)。利用CaCO3和H2SO4培养法分析则发现,初始反应为酸性的土壤,其pH值与酸碱加入量呈显著的线性相关关系(P<0.05),但潮土和乌栅土除外。研究结果表明,以无CO2蒸馏水进行浸提,运用HCl和NaOH进行滴定的方法测定土壤酸碱缓冲容量对不同土壤类型都具有较好的适应性。利用该方法对长期不同施肥条件下太湖地区水稻土酸碱缓冲容量进行测定发现,各施肥处理土壤酸碱缓冲容量为19.6~24.8 mmol/kg;太湖地区黄泥土酸碱缓冲容量受土壤有机质含量及阳离子交换量的影响,增施猪粪和施用过磷酸钙是提高该土壤酸碱缓冲能力的重要举措。

By determination of soil acidity buffering capacity(pHbc),the anti-acidification ability of soils can be evaluated and the acidization of soils can be understood,thus provide basis for the remediation of acidified soils.To explore the suitable method for determining pHbc of different soil types,fluvo-aquic soil and red soil from partial typical regions and paddy soil from Taihu Lake region of China were used as the objects,acid-base titration method and culturing method for measuring pHbc were compared and analyzed.The results showed that the pH values of the jump rang analyzed by HCl-NaOH titration method showed highly significant(P<0.01,except for the red soil extracted by CaCl2 solution)linear relationship with the volumes of the acid or base added,using CO2-free deionized water and CaCl2 solution(0.01 mol/kg)in the leaching of soils,and the mass ratio of soil to solution was 1.0 to 2.5.Analysis on the results of CaCO3 and H2SO4 incubation methods showed that,for the acid soils according to initial reaction,the relationship between the adding amount of acid or base and soil pH values showed significantly linear regression correlation(P<0.05),except for fluvo-aquic soil and Wuzha soil.The results indicated that pHbc detected by the HCl-NaOH titration method showed good adaptability for different soils types,using CO2-free deionized water in leaching.The pHbc of paddy soil under long-term fertilization conditions in Taihu Lake region determined by the method showed that,the pHbc ranged from 19.6 mmol/kg to 24.8 mmol/kg.The pHbc of yellow soil in Taihu Lake region was affected by content of soil organic matter and cation exchange capacity,and the application of pig manure and superphosphate had positive effects on enhancing soil pHbc.