落叶松人工林土壤肥力变化的研究阎德仁(内蒙古林业科学研究院呼和浩特市010010)SoilFertilityVariationsUnderArtificialLarchForest¥.YanDeren(ForesiryInstiluteofInnerMongolia,Huhhot010010).ChiineseJournalofEcology,1993,12(3):8-10.Thispaperstudiesthevariationofsoilfertilityunderpureartificiallarch(Larixgmelinii)forestfromas-pectsofsoilhumusandenzymeactivity.Withincreasingageofforeststand,soilfertilitytendstode-crease,butsoilenzymeactivitytendstoincrease.Underforestwith20yearsofage,thecontentsofsoilhumus,humicacidandfulvicacidandtheratioofhumicacid