水旱轮作对砂姜黑土腐殖质状态和组分的影响

Study of Combined Forms and Fractional Composition of Humus of the Black Meadow Soil in Wet-dry Cropping Rotation

研究了旱作改水旱轮作不同年限的砂姜黑土腐殖质状态和组分的变化，结果表明：轮作制度的改变引起土壤水热条件的剧烈变化，从而影响土壤有机无机复合体和腐殖质的状况。随着水旱轮作时间的延长，土壤有机无机复合度下降，紧结态复合体所占的比例增加，胡敏素含量也相应增加。旱改水初期，ＨＡ／ＦＡ比例减小，随后趋于增大。

Soil humus forms and fractional composition of the black meadow soil form dry-croppingsystem and wet-dry cropping system with different rotation transforming time.The result indicat-ed that as the rotation transforming time was prolenged,was analysed.The degree of complexingin organic-mineral soil complexes decreased ,the proportion of tightly combined complex in totalorganic-mineral soil complexes increased ,and the content of humin increased accordingly.At thebeginning of system transforming,the humic acid-futvic ratio(HA/FA)decreased first and thenincreased.Thus it is concluded that because it takes a long time to approach ecological balance af-ter establishing a new croping system and the transforming cropping rotation result in a sharpchang on soil hydrothermal condition ,the organic-mineral soil complexes and humus fractionalcomposition cannot become stable within a short period.