东北典型黑土区坡耕地涝渍地土壤化学性状

Soil Chemical Characteristics of the Waterlogged Land on Slope Cropland in Typical Black Soil Region of Northeast China

中国东北典型黑土区是我国重要的商品粮生产基地,对我国粮食安全和国民经济的稳定起到举足轻重的作用。作为土壤退化的一种特殊形式,涝渍地严重影响着垦区的农业生产。在东北典型黑土区坡面涝渍地及其周围正常耕地中布设采样点,测定了土壤氧化还原性及相关指标,以揭示坡耕地涝渍土壤与其周围耕种土壤化学性质的差异,得出涝渍土壤所具有的特殊化学性状。结果表明:涝渍土壤与耕种土壤化学性质差异显著。涝渍土壤属于酸性土壤,pH值为5.53,显著低于耕种土壤,有机质含量较高,且越接近涝渍地中心土壤有机质含量越高。涝渍土壤Eh显著低于耕种土壤,空间变异范围较大,但还没有达到强度还原状态。涝渍土壤在长期淹水条件下,大量的Fe3+、一部分高价锰被迅速还原,与耕种土壤相比,涝渍土壤还原性物质总量较高,高出20倍多,亚铁含量高出12倍还多,二价锰含量高出约10倍。

The typical black soil zone in northeast China is an important commodity grain production base and plays crucial roles in the national food security and economic stability.As a special form of soil degradation,waterlogged lands severely affect the agricultural production in reclamation regions.The objective of this study was to analyze the differences of soil chemical characteristics between waterlogged land and the normal cultivated land and to try to find the special soil chemical characteristics of waterlogged land.The sampling points were set in and around the waterlogged land on the slope cropland in typical black soil region of northeast China.The oxidation and reduction properties-related indicators of soil were measured.The results showed that the differences in soil chemical characteristics between waterlogged land and the normal cultivated land were significant.The soil pH value(5.53)in waterlogged land is significantly lower than that of the normal cultivated land.The soil in waterlogged land has higher organic matter and the higher organic matter is found in the central zone of the waterlogged land.Eh in waterlogged land is lower and the spatial variation range is larger than that of normal cultivated land.But the soil in waterlogged land has not reach the strength reduction status.Much Fe3+and part of manganese ion with high valence are reduced rapidly because the soil in waterlogged land keeps high water content for a long term.The total reducing substances,ferrite iron content and bivalent manganese content of waterlogged soil are 20 times,12times and 10 times higher than those of the normal cultivated soil,respectively.