南通市城市边缘带土壤肥力时空特征分析

基于野外土壤调查与样品分析数据,应用数理统计分析方法,揭示了南通市城市边缘带土壤肥力特征、影响因素、变化趋势以及时空规律。结果表明,研究区土壤表层有机质、土壤全量与速效养分含量空间变异明显,速效养分尤其具有高度的空间可变性,表现出城市边缘带土壤属性的重要特征。样点土壤肥力要素方差分析结果显示,土壤肥力特征的空间变异与本区土地利用变化历史与人为活动的时空分异密切相关;而土壤机械组成及全K含量空间变化不大,受控于土壤类型的空间分布,反映了本区土壤的发生学特点。经过过去20年的农业生产实践,研究区土壤多数肥力要素明显改善、肥力水平明显提高,但影响土壤肥力质量、制约土壤资源可持续利用的不利因素依然存在。

Spatio-Temporal Characteristics of Soil Fertility in the Peri-Urban Areas of Nantong City

Based on data obtained from field soil investigations and laboratory analysis, status, spatio-temporal variation and evaluating tendency of soil fertility in the peri-urban areas of Nantong were studied, with the aid of the mathematical statistics-based analysis methods. It was indicated that contents of OM, total and available N, P in topsoil (0-20 cm) varied greatly across the study area, demonstrating a strong influence of land use practices on soil fertility. By contraries, CEC and content of total K in topsoil displayed very little variation across the space, reflecting some common genetic characteristics (light texture and K-rich parent materials) of the soils in the area. Compared to the data obtained in the period of the Second National Soil Survey conducted in 1986, the contents of OM, total N, P increased by more than 50%, while the contents of total K remained almost unchanged in topsoil of the study area. And available P increased by 5 times, while available K did just slightly only by less 3%. Taking all of the samples as a whole, pH of the topsoil significantly decreased in the area. Generally speaking, intensive agricultural practices during the last 20 years made the soils of the peri-urban areas of Nantong much more fertile and productive. It must be mentioned that, however, in spite of the increase in contents, balance of soil nutrients was becoming worse, and some soil quality affecting factors were still there. Meanwhile, strong spatial variation of soil attributes caused by diverse agricultural practices was leading to complication of the soil resource structure in the area, thus bringing about a more serious challenge to sustainable use and management of the regional soil resource in the peri-urban areas of Nantong.