在沈阳地区棕壤上设置长期定位试验。结果表明，凡经１５年在玉米—大豆—玉米轮作条件下连续施用猪厩肥和ＮＰＫ化肥，耕层土壤胡敏酸Ｃ相对下降５４５％，富里酸Ｃ相对提高１６２６％，ＨＡ／ＦＡ比由１９７９年的２６９降到１９９３年的０４６，土壤腐殖质组成以胡敏酸为主体转化为以富里酸为主体。本文还讨论了不同施肥处理对腐殖酸消长的影响。 Set long-term positioning test on brown soil in Shenyang area. The results showed that when the pig manure and NPK fertilizers were applied continuously for 15 years under the conditions of corn-soybean-corn rotation, the soil humic acid C decreased by 545%, the content of fulvic acid C increased by 1626%, HA / FA ratio dropped from 269 in 1979 to 046 in 1993. Humic acid was the main component of soil humus composition and was converted to fulvic acid. This article also discussed the impact of different fertilization treatments on the growth and decline of humic acid.