用酸碱滴定曲线拟合参数表征土壤对酸缓冲能力的新方法  

New Method for Evaluating Buffering Capacity and Equilibrium pH of Paddy Soil with Simulation Parameter

作　　者：成杰民[1,2] 胡光鲁[3] 潘根兴[4] 

机构地区：[1]山东师范大学人口资源与环境学院 [2]南京农业大学资源与环境科学学院,江苏南京210095 [3]山东青年干部管理学院信息工程系 [4]南京农业大学资源与环境科学学院

出　　处：《农业环境科学学报》2004年第3期569-573,共5页Journal of Agro-Environment Science

基　　金：国家自然科学基金(D40271068);山东省自然科学基金(Y2002E02)

摘　　要：以太湖地区3种对酸缓冲能力不同的水稻土(黄泥土、白土和乌泥土)为供试土壤,以不同pH值(pH为5.6,4.0,3.0,2.0)的模拟酸雨淋溶,研究模拟酸化条件下土壤酸碱缓冲能力的变化。根据酸碱滴定曲线,进行统计分析和数学拟合,提出以酸碱滴定曲线拟合方程的斜率表征土壤酸缓冲能力的新方法。结果表明,3种供试土壤酸碱的基础缓冲能力依次为黄泥土(β=3.25)、乌泥土(3.00)、白土(1.58);土壤酸碱滴定曲线在其突跃范围内,加酸的量与pH呈显著线性负相关;直线斜率b的绝对值用以定量土壤对酸碱缓冲能力,b的绝对值越大,土壤酸碱缓冲能力越差。K值用以定量说明土壤酸碱缓冲能力的变化,当K>100%时,K值越大,土壤酸缓冲能力降低越多;当K<100%时,K值越小,土壤酸碱缓冲能力增加越大;当K≈100%(≤±5%)时,可视为土壤酸碱缓冲能力无显著变化。因新方法的理论依据仍为酸碱滴定曲线的理论,所以仅适用于反应动力学上较快的阳离子交换反应,即土壤酸碱初级缓冲体系,不适用于原生矿物的风化的土壤酸碱次级缓冲体系。其结果为研究土壤酸碱缓冲能力的变化,乃至研究土壤环境质量变化提供了可靠的定量方法。A method for evaluating acidic sensitivity of soils was studied in this investigation. The changes of acid buffering capacity of three typical paddy soils (Hydragric paddy soil, Bleached paddy soil and Gleyed paddy soil) from the Tai Lake region, China, were analyzed under simulated acidification with acid rain (pH values 5.6, 4.0, 3.0 and 2.0). The parameters for estimating acidic sensitivity of soils were statistically gained by using the titration curve of acid and alkali. The results indicated that acid buffering capacities of hydagric paddy soil, gleyed paddy soil, and bleached paddy soil were 3.25, 3.0 and 1.58, respectively. The steep change of pH in the titration curve of each soil was best linearly fitted by the amount of acid addition after 70 days. The higher absolute value of slope was the soil with less acidic buffering capacity. The ratio of the slope before leach and the slope after leach may be used to estimate the change of acidic buffering capacity of a soil under acidification. The higher or lower ratio( K>100% or K<100% =indicated the more intense change of the buffer capacity to acid and alkali. The more approached to 100% (≤ ± 5% ) the value( K) was, the smaller the buffer capacity to acid and alkali changed. Because the new method was based on the theory of titration curve of acid and alkali of the soil, it could be used only in the system of cation exchange reaction in soil.

关 键 词：水稻土 酸碱缓冲能力 拟合参数 

分 类 号：S114[农业科学—农业基础科学]