不同配比的杉木、火力楠凋落物中土壤酶活性的变化及其对凋落物分解的影响

以酸雨区不同配比的杉木、火力楠凋落物(A 1∶0、B 0∶1、C 1∶1、D 1∶2、E 2∶1)为对象,研究凋落物分解速率、凋落物及表层土壤酶活性及其对凋落物分解速率的影响.结果表明,分解300 d时不同配比杉、火凋落物分解速率排列顺序为处理B(27.93%)处理D(25.99%)处理E(24.55%)处理C(21.78%)处理A(21.07%).不同配比杉、火凋落物酶活性均高于表层土壤酶活性.不同配比凋落物的纤维素酶活性在分解180 d时最高,在分解300 d时最低.表层土壤酶活性随分解时间变化显著,酸性磷酸酶活性在分解120 d时最低,在分解300 d时最高;纤维素酶和蔗糖酶的活性随分解时间呈递减趋势,分解300 d时达到最低.凋落物分解速率与凋落物多酚氧化酶、酸性磷酸酶活性呈正相关,与凋落物和表层土壤的纤维素酶活性、蔗糖酶活性呈负相关.

Enzyme activity of litter and soil and its effect on litter decomposition under different combinations of Cunninghamia lanceolata and Michelia macclurei

By mixing thoroughly litters of Cunninghamia lanceolata and Michelia macclurel from acid rain region in different propor-tions ( A 1:0,B 0:1,C 1:1,D 1:2,E 2:1) , litter decomposition rate and enzyme activity of litter and topsoil were measured. The results showed that after 300-day decomposition, decomposition rates of litters in different proportions increased as follows: B (27.93%)>D(25.99%)>E(24.55%)>C(21.78%)>A(21.07%), and enzyme activities of litters were always higher than those of topsoil. The cellulose activity of litters peaked on day 180 and hit bottom on day 300, while there was no obvious tendency in the variations of other enzyme activities. The enzyme activity of topsoil varied significantly during decomposition period, with acid phos-phatase minimizing on day 120 and peaking on day 300. Cellulose and sucrose activities decreased along decomposition time, and reached the lowest level on day 300. The litter decomposition rate was positively correlated with litter polyphenol oxidase and acid phosphatase activity, and negatively correlated with cellulase activity and sucrase activity in both litter and topsoil.