水田改雷竹林后土壤发生学性质和土壤类型的演变

Evolution of Genetic Characteristics and Types of Soils Transformed into Lei Bamboo Forest from Paddy Fields

从浙江省临安市采集了水田及其改雷竹林的4个系列土壤(包括长期种植水稻的农田、水田改种雷竹6年、12和15年的农地)的代表性剖面的分层样品(种雷竹前土壤为发生学分类中的黄泥田,属系统分类的铁聚水耕人为土),采用田间形态观察与室内理化分析相结合的方法对土壤进行了鉴定。结果表明,黄泥田种植雷竹后土壤人为滞水水分状况消失,逐渐向湿润水分状况转变;水耕条件下形成的水耕表层因深耕被破坏而逐渐消失,而水耕氧化还原层的特征可残留在土体中;土壤有机碳和磷素明显积累,土壤中络合态铁显著增加。与此同时,土壤类型也逐渐由普通铁聚水耕人为土向普通铁质湿润雏形土、最后向黄色铝质湿润雏形土演化。结果表明,人为的强烈影响可使土壤类型在短时间尺度内发生改变。

Four soil sequences with different history of land use were collected respectively from Linan city, Zhejiang province for studying the changes in genetic characteristics and types of soils after transformation from paddy fields to Lei Bamboo(Phyllostachys praecox) Forest. The land uses in the soil sequence included long-term paddy field, Lei bamboo forests transformed from paddy field with 6, 12 and 15 years. The results showed that, several years after transformation from paddy fields to Lei bamboo forest, anthrostagnic soil moisture regime in the stagnic anthrosols disappeared, and turned into udic soil moisture regimes. Meanwhile, redox features of anthrostagnic epipedon formed under former anthrostagnic cultivation were significantly altered. Contents of organically-bound Fe in soils increased and soil colour tended to be black. But the transformation of paddy field to Lei bamboo forest did not affect the contents of total and free iron oxides in the soils and their profile distribution patterns. Also, it did not affect types and abundance of Fe and Mn mottling and concretions in hydragric horizon. At the same time, soil type was also evolved into typic Ferri-udic Cambisols from typic Hapli-Fe-accumuli- Stagnic Anthrosols, and finally to Xanthic Ali- udic Cambisols. The results suggest that the strong influence of artificially activity can make the soil type change in a short time scale.