秸秆还田条件下内陆盐碱土腐殖质的动态变化

Dynamic Changes of Humus in Inland Saline-alkali Soil in Field with Post-harvest Crops Returning

采用室内培养试验的方法，研究了秸秆加入条件下内陆盐碱土的腐殖质及其组分（胡敏酸、富里酸）的动态变化。结果表明，在秸秆腐解过程中，盐碱土腐殖质、富里酸、胡敏酸含量均呈现持续上升趋势，分别平均增加了112．5％，269．54％和92．9％；富里酸的含量明显高于胡敏酸的含量，是胡敏酸含量的约3～10倍。土壤的HA／FA（腐殖酸／富里酸）呈现出先增长后降低的趋势，并且在90d时达到平均最高值（0．283）。尿素添加量7．2g的处理土壤腐殖质含量在0．19％～0．38％，该处理秸秆分解的速率最快。土壤腐殖质和富里酸随着尿素含量梯度的增加呈现先上升，后下降，再上升的趋势，且分别平均增加了46．7％和55．3％；胡敏酸的变化趋势与腐殖质相反，平均减少了14．3％；HA／FA呈下降趋势，但下降趋势不明显。

This paper studied the dynamics changes of soil humus and its composition[humic acid（FA） and fulvic acid（FC）] in the field with post-harvest crops returning. The results showed that humus, fulvic acid and humic acid contents in the saline-alkali soil increased by 112.5%, 269.54% and 92.9% respectively after the decomposition of the straws. The content of fulvic acid was 3-10 times of humic acid. HA/FA of saline- alkali increased at first and then decreased with the highest value of 0. 283 on the 90th day. Humus content was between 0. 19% and 0.38% with the fastest straw decomposition treatment of adding 7.2 g urea. The content of humus and fulvic acid increased at the beginning, then decreased and increased at the end with in- crease of urea addition. The humus content increased 46.7% while the fulvic acid increased 55.3% and humic acid was quite opposite and decreased by 14.3% on average. HA/FA decreased but was not obvious.