近20年来江苏省土壤pH值时空变化及其驱动力

通过比较1980年和2003年江苏省土壤pH空间分布图,发现虽然两个时期土壤pH空间分布的基本格局仍然相似,表现为南酸北碱,但局部地区也存在较大的变化,主要表现为酸化.沂沭岗地浅洼平原土区、里下河浅洼地土区、宁镇扬低山丘陵土区和太湖平原土区均有较严重的酸化出现.分析发现前两者主要受不合理施肥、田间管理和土地利用及种植类型变化的影响,后两者除以上的影响因素外还包括工业化和城市化.另外在后两者和宜溧洞庭山地土区由于土地利用和种植方式的变化、建筑和道路的兴建,还导致了局部地区土壤pH有所上升.土类中潮土酸缓冲性能强、pH变化不大,水稻土pH下降严重,特别是里下河浅洼地土区水稻土,在现有的管理利用方式下,继续下降的可能性很大.

Spatio-temporal variation and associated affecting factors of soil pH in the past 20 years of Jiangsu Province, China

The changes of soil pH significantly affect soil chemical properties and even whole environmental ecosystems. For this reason, the studies on them have attracted and con acidification is being accelerated with rapid industrial deve great deal of eco-environmental problems. Some authors tinue to attract much academic attention. Especially the soil lopment and unreasonable farming practices, which has led to a have conducted much research on the effects of some unique affecting factors on soil pH changes in some relatively uniform regions. However, in-situ studies of their comprehensive effects on soil pH changes in some complex regions have been seldom investigated. In this study, the spatio-temporal variation and associated factors which affect soil pH changes of Jiangsu province with high rapid industrial development and dense population were discussed by comparing the two spatial distribution maps of soil pH in 1980 and 2003. The results showed that the spatial distribution pattern of soil pH in 2003 was similar to that in 1980 with lower soil pHs in the south part of the province than those in the north because of the difference of soil types. However, significantly decreasing changes were also observed in some local regions from 1980 to 2003. Intensively acidified soils were identified in Yishu mound and depressed plain soil region, Lixiahe depressed plain soil region, Ningzhenyang low mountain and undulated soil region, and Taihu Lake plain soil region. In the former two regions the dominant affecting factors on decreased soil pH are farming practices such as fertilizing, incorporation of crop residues and soil utilization. As for the latter two, besides farming practices, industrialization and urbanization also are main affecting factors. Soil pH has increased in some areas of Ningzhenyang low mountain and undulated soil region and Taihu Lake soil region mainly due to soil utilization changes, structures, and road construction. Among soil groups, pH changes of Fluvo-aquic soils in the past 20 years were not significant, but those in paddy soils significantly decreased, particularly in the Lixiahe depressed plain soil region where decreasing trend of soil pH may be accelerated. This is because acidic buffering capacity of Fluvo-aquic soils is greater than that of paddy soils. In conclusion, farming practices, industrialization and urbanization are important affecting factors of soil pH changes and have led to significantly changes in some local regions. In order to the soil sustainable utilization in rapid economic developing regions, the government must mention the soil pH changes and take some effective measures to adjust and guide agriculture and industry so that the sparse soil resources in the densely populated area can be appropriately utilized.