宜兴地区土壤pH值的分布特征及时空变化

Distribution properties and time-series comparisons of soil pH-values in Yixing area

对宜兴地区2004、2009和2015年的土壤地球化学调查数据进行分析,土壤pH值变化于3.53~8.86之间,其中酸性和强酸性土壤主要分布在低山丘陵砂岩地层分布区,微碱性土壤主要分布在石灰岩地层分布区,平原区土壤以微酸性为主,反映了成土母质、地形地貌对土壤pH值的影响。对比研究表明,过去6年间宜兴地区有49.77%的土地pH值处在下降之中,有23.53%的土地pH值处在上升之中,只有26.70%的土地pH值基本没有变化。由于工业化发展对环境的改变,本区土壤酸化受酸雨沉降影响明显。在成土作用、酸雨沉降、农耕等多因素的长期影响下,平原区表层土壤要比底层土壤pH值低1.2左右,表层土壤酸化主要发生在耕作层,深度在30 cm左右,底层土壤基本为中性。总体来看,宜兴地区10多年来表层土壤呈酸化趋势,如果没有相应的措施,继续下降的可能性很大。

The geochemistry survey analysis was conducted on the soil samples collected from the Yixing area in 2004,2009,and 2015 years,and the results show that the pH-value of surface soil varies from 3.53 to 8.86. Specifically,the acidic soils and strongly acidic soil generally distribute in the distribution of hill sandstone strata. The weak alkaline soil generally distributethe in the distribution of limestone strata. In the alluvial lake plain area,most soil is weakly acidic. And it shows the soil parent material and topographic features impact soil PH-values. Comparing with the changes of the surface soil pH-values within the past six years,the result show that there are 49.77% soils with decreased pH-value,the 23.53% soil with increased pH-valua,and 26.70% soils with relative stable PHvalue. Due to the impacts of industrialization development on the environment,the acid rain plays an important role in soil acidification.Affected by farming and among others,the pH-value of surface soil in the alluvial lake plain area are lower than those of deep layer soil by around 1.2. The acidification of the surface soil occurs mainly in the tillage layer,the depth is about 30 cm,and the bottom soil is basically neutral. From the general point of view,the analytical results of surface soil in the Yixing area show a trend of acidification.Some necessary measures must be done to prevent further deterioration.