黄河三角洲湿地景观边界变化及其对土壤性质的影响

Landscape Change and Its Effects on Soil Properties in the Yellow River Delta

以1992年和2006年TM遥感影像为基础信息,运用滑箱扫描方法获得组分边界特征,分析了黄河三角洲景观总体变化,在此基础上,研究不同景观类型变化过程土壤容重、水分含量、全氮、全磷、有机质及土壤盐分离子Ca2+、K+、Mg2+、Na+的差异性,以揭示景观变化对湿地土壤性质的影响。结果表明,三角洲景观组分之间的边界趋于复杂化,部分耕地转化为柽柳(Tamarix chinensis)、芦苇(Phragm ites australis)和翅碱蓬(Suaeda heterop-tera),潮滩植被侵入滩涂。不同景观类型下的土壤性质差异不显著,但景观类型转化对土壤性质存在一定影响。农田转变为柽柳、芦苇、翅碱蓬过程中土壤容重降低;而滩涂转变为翅碱蓬后土壤容重提高。农田转化为林地和滩涂转化为灌丛过程中土壤含水量降低,而其他景观变化过程土壤含水量表现出增加的趋势。不同景观类型下土壤全氮、有机质、全磷含量均较低,且变化过程中土壤养分含量变化也较小。各景观类型变化过程中土壤Ca2+含量变化幅度最大;其他土壤盐分离子含量的变化因景观组分变化方向不同存在较大差异,但总体上看,不同景观变化过程下土壤盐分离子含量均具有较大变化。

Using remote sensing and geographical information system in the Yellow River Delta were analyzed. Variations of soil water technologies, changes of landscape boundary content, bulk density, total nitrogen, total phosphorus, organic matter as well as concentrations of Ca^2＋ , K^＋ , Mg^2＋ and Na^＋ , under different landscape conversions, were investigated. Soil samples from one-hundred and eight locations were sampled and their - properties were compared. The results showed that during 1992 -2006, the boundary characteristics became more complicated and farmland was converted to Tamarix chinensis, Phragmitas communis and Suaeda heteroptera Kitagawa. Though there was no significant difference in soil properties between different landscape types, conversions between them had effects on soil properties to some extent. Soil bulk density decreased under removal of cultivation and intense disturbances, while it increased when bare beach was occupied by halophytic vegetation. Soil water content decreased under the conversions from farmland to woodland and from beach to brush, while it increased under other conversions. As to soil nutrients, the content of total nitragen, total phosphorus and organic matter was low under different landscape types and the variance was small. Besides, the Ca^2＋ concentration was higher than other basic cations and there was significant difference of Ca^2＋ concentration between different landscape types. Similarly, difference was found for K^＋, Mg^2＋ and Na^＋ between different landscape types. In general, landscape conversions had effects on soil salinity ion changes and significant differences were found for some landscape conversions.