外源性氮和磷对杉木和藜蒴锥混合凋落叶分解的影响

Effects of N and P Additions on Mixed Leaf Litter Decomposition in Cunninghamia lanceolata and Castanopsis fissa Plantations

2007年12月在广东省佛山市高明区云勇林场的杉木和藜蒴锥林下以不施肥为对照,采用完全随机区组试验设计,进行施N肥、施P肥及施N+P肥等处理,分析华南地区杉木和藜蒴锥人工林的混合凋落叶分解对外源性N和P的响应。结果表明:施N对杉木和藜蒴锥林下混合凋落叶的分解有抑制作用,而施P的凋落叶分解速率最快,施N+P也促进了凋落叶分解。总体来看,藜蒴锥林下混合凋落叶的分解速率大于杉木林下的混合凋落叶。24个月后,杉木林下施N和N+P的混合凋落叶N含量显著大于其初始含量,而藜蒴锥林下各处理的混合凋落叶N含量均小于其初始含量;在杉木和藜蒴锥林下,施P和N+P的混合凋落叶P含量均显著大于其初始含量;混合凋落叶K含量在整个分解过程中波动较大。

December 2007, mixed leaf litter decomposition with N and P additions in Cunninghamia lanceolata and Castanopsis fissa plantations of South China was studied at Yunyong forest farm of Gaoming district, Foshan, Guangdong. Completed random was introduced to N, P and N＋P addition treatments, and the plantations with no fertilizer as the control. The findings showed that decomposition rate of mixed leaf litter under C.lanceolata and C.fissa plantations was postponed by N addition and accelerated by P and N＋P addition treatments. Decomposition rate of mixed leaf litter under the C.fissa plantation was faster than that under the C.lanceolata plantation. Twenty-four months after the decomposition, the N content of mixed leaf litter with N and N＋P additions was greater than their initial N content in the C.lanceolata plantation, whereas that with all treatments was significantly smaller than their initial N content in the C.fissa plantation. The P content of leaf litter with P and N＋P additions was significantly greater than its initial P content in the C.lanceolata and C.fissa plantations. The K content of leaf litter fluctuated greatly during the whole decomposition period.