分解促进剂对九龙山林下凋落叶分解的影响

Effects of decomposition accelerator on litter decomposition in Jiulong Mountain of Beijing

针对北京九龙山林下凋落叶分解缓慢、极易导致火灾发生等问题,采用凋落物分解袋法研究不同分解促进剂对凋落叶分解过程的影响.采用尿素(N)、益生菌(EM)、饲用复合酶制剂(S)及本地真菌环炳菇(Lepiota)(以下用F.L表示)和杯伞(Clitocybe)(以下用F.C表示)对栓皮栎、油松凋落叶及栓皮栎与油松1∶1的混合凋落叶进行研究.结果表明:(1)喷施分解促进剂后,各种类型凋落叶分解速率差异较大,栓皮栎分解最快,栓皮栎与油松的混合凋落叶次之,油松分解最慢.(2)经过18个月的分解,栓皮栎与油松的混合凋落叶在F.L处理下,失重率最大,达到37.9%;栓皮栎凋落叶在F.C处理下,失重率最大,达到38.7%;油松凋落叶在S处理下失重率达32.9%,这3种处理下的凋落叶失重率均显著高于对照组(P<0.05).(3)通过指数模型回归分析可以看出,栓皮栎凋落叶在F.C处理下分解最快,95%分解时间为10.0 a;栓皮栎与油松混合凋落叶在F.L处理下分解最快,95%分解时间为12.5 a;油松凋落叶在S处理下分解最快,95%分解时间为13.3 a.说明分解促进剂对凋落叶分解有一定的促进作用,但不同类型凋落叶所适用的分解促进剂也不同.针对不同类型凋落叶,选出分解凋落叶最快的促进剂种类,对减少森林火灾有一定意义.

To reduce forest fire attributed to heavy forest litter in Jiulongshan Mountains in Beijing.Litter decomposition bag method was used to study the effects of different accelerants on litter decomposition.Five types of accelerants were tested,which included u rea(N),complex emzyne(S),probiotices,Lepiota(F.L)and Clitocybe(F.C)from litter from Jiulong Mountain.The results showed that broadleaf decomposed fastest,which was followed by mixed forest of coniferous and broadleaf,and coniferous litter.Af ter 18month decomposition,decomposition rates of different types of litter were all significantly higher than the control(with the ad dition of water)(P<0.05).The weight loss rate of mixed forest of coniferous and broadleaf was the highest under the treatment of F.L,reaching 38.7%,which was estimated to take 12.5 years to decompose 95%litter according to regression analysis of exponen tial model.While the weight loss rate of broadleaf peaked under the treatment of F.C,reaching 37.9%,which was estimated to take 10 years to decompose 95%litter.The weight loss rate of coniferous litter maximized under treatment S,reaching 32.9%,which was estimated to take 13.3 years to decompose 95%litter.To summrize,choosing the appropriate accelerator based on the feature of litter is the priority when applying accelerator for reducing forest fire.