土壤动物对川西高山/亚高山森林凋落物分解的贡献

Contributions of soil fauna to litter decomposition in alpine/subalpine forests

采用凋落物分解袋法,研究了土壤动物对川西高山/亚高山森林代表性植物康定柳、方枝柏、红桦和岷江冷杉凋落物在分解第一年(2011年11月—2012年10月)不同关键时期质量损失的贡献.结果表明:在凋落物第一年的分解过程中,不同物种凋落物的分解速率大小依次为康定柳>红桦>岷江冷杉>方枝柏,且均为生长季节大于冻融季节.土壤动物对凋落物分解的贡献率(P fau)为方枝柏(26.7%)>岷江冷杉(18.8%)>红桦(15.7%)>康定柳(13.2%),其中康定柳和方枝柏的P fau在生长季节大于冻融季节,而红桦和岷江冷杉的P fau为冻融季节大于生长季节.冻融季节土壤动物的作用与凋落物初始C、P和N/P显著相关,而生长季节则与N、C/N、木质素、木质素/纤维素显著相关.

A field experiment was conducted using the litterbag method to quantify the contribution of soil fauna to litter mass loss of Salix paraplesia, Sabina saltuaria, Betula albosinensis and Abies faxoniana during different key periods of the decomposition process of the first year （ from November 2011 to October 2012）. The results showed that the mass loss rate showed S. paraplesia 〉 B. albo- sinensis 〉 A. faxoniana 〉 S. saltuaria, and the rate in the growing season was greater than in the freeze-thaw season. The contribution rate of soil fauna to the mass decomposition displayed as S. saltuaria （26. 7% ） 〉A. faxoniana （ 18. 8% ） 〉 B. albosinensis （ 15. 7% ） 〉 S. paraplesia （ 13.2% ） , which was higher in the freeze-thaw season than in the growing season for litter of B. albo-sinensis and A. faxoniana while vice versa for litter of B. albosinensis and A. faxoniana. The contribution of soil fauna was mainly related to organic C, P and N/P in the freeze-thaw season, while N, C/N, lignin and lignin/cellulose in the growing season.