黄淮海平原典型潮土的酸碱缓冲性能

 【目的】通过对土壤酸碱缓冲容量的研究，可以评价土壤抵抗酸化和碱化的能力，也可以对土壤酸化过程进行预测和调控。【方法】采用酸碱滴定法获取土壤酸碱滴定曲线，并通过分段拟合计算土壤酸碱缓冲容量。【结果】酸滴定曲线和碱滴定曲线在整体上并不呈线性，但分段的酸和碱滴定曲线的线性相关系数均大于0.97。通过分段拟合得出土壤酸、碱缓冲容量分别为158.71和25.02 mmol?kg-1。【结论】酸碱滴定法适用于黄淮海平原典型潮土酸碱缓冲容量测定。根据缓冲体系的划分和土壤基本性质可以看出，碳酸盐是最重要的酸缓冲体系，而土壤有机质贡献相对较小。

Acid and Alkaline Buffering Capacity of Typical Fluvor-Aquic Soil in Huang-Huai-Hai Plain

【Objective】 Soil acid and alkali buffer capacity, as a major indicator for evaluating the vulnerability and resistibility to soil acidification and alkalization, is an important factor impacting the sustainable development of agricultural soils, through which soil acidification process can be predicted and modified. 【Method】 In this study, titration curve method was adopted to investigate the pHBC, and separate titration curves were established by adding incremental amounts of either standardized hydrochloric acid (HCl) (0.12 mol?L-1) or sodium hydroxide (NaOH) (0.10 mol?L-1) to soil suspended in deionized water (soil﹕solution = 1﹕5). Soil pH was measured after 7d resuspension and isothermal equilibrium (t =25℃). Linear regressions were fitted to the linear portion of each titration curve and the slopes of these lines were used as the determination of pHBC. 【Result】 The results showed that great significance of correlations between the amounts of adding acid or alkali and the pH drop or increase were presented, and the coefficients of relativity were higher than the similar researches on acid soils (R2 = 0.97). The slope-derived pHBC of acid and alkali were 158.71 mmol?kg-1 and 25.02 mmol?kg-1, respectively. 【Conclusion】Titration technique was applicable in determination of pHBC on typical fluvor-aquic soil in Huang-Huai-Hai Plain. According to the classification of soil buffer systems, the soil studied belongs to the calcium carbonate buffer system, and in contrast to the soil organic matter, the carbonates contribute the most to pHBC.