氮磷添加对红壤区城郊湿地松林凋落叶分解的影响  

Effects of nitrogen and phosphorus addition on leaf litter decomposition in a suburban slash pine plantation in red soil region of China

作　　者：弓晓静[1] 余明泉[2] 胡小飞[1] 郭恢财[1] 陈伏生[1] 

机构地区：[1]南昌大学生命科学与食品工程学院,南昌330031 [2]江西科技师范学院生命科学学院,南昌330038

出　　处：《生态学杂志》2010年第12期2327-2333,共7页Chinese Journal of Ecology

基　　金：国家自然科学基金资助项目(30960311和30600473)

摘　　要：城市化易导致城市森林氮(N)沉降和磷(P)富集,进而对凋落物分解过程产生影响。以位于南昌市郊的湿地松(Pinuse lliottii Engelm.)林为研究对象,采用尼龙网袋分解法,模拟N沉降(10g N·m-2·a-1,[N])、P积累(2.5g P·m-2·a-1,[P])和N沉降+P积累(10N·m-2·a-1+2.5g P·m-2·a-1,[N+P])对凋落叶分解速率与C、N、P含量及其化学计量比动态变化的影响。结果表明:与对照(CK)相比,[N]、[P]和[N+P]均促进凋落叶的前期(0～180d)分解速率,抑制中期(180～360d)、后期(360～540d)的分解速率;至540d时分解速率表现为[N]、[P]和CK无差异,但均高于[N+P](P<0.05)。[N]提高分解过程中凋落叶N浓度,N含量表现为分解前期积累、后期释放;[P]提高分解过程中凋落叶P浓度,P含量持续积累;[N+P]提高N和P浓度,分解前期N、P含量积累,后期释放;而不同处理的C含量均表现为释放。凋落物基质C/N/P比与分解速率的相关性随分解阶段而表现各异。综合来看,城市化导致的N沉降和P富集叠加效应具有抑制城市森林凋落物分解过程的潜在性。Litter decomposition in urban forests may be influenced by the elevated nitrogen （N） deposition and phosphorus （P） enrichment during rapid urbanization. In this paper,nylon litter bag method was used to simulated the effects of N deposition （10 g N·m^-2·a^-1,[N]）,P enrichment （2.5 g P·m^-2·a^-1,[P]）,and their combination （10 g N·m^-2·a^-1＋2.5 g P·m^-2·a^-1,[N＋P]） on the decomposition rate,nutrient contents,and nutrient stoichiometric ratios of the litters in a Pinus elliottii Engelm. plantation in the suburb of Nanchang City,China. Compared with CK （without N and P addition）,treatments [N],[P],and [N＋P] increased the decomposition rate of the litters at early stage （0-180 d）,but decreased it at the middle （180-360 d） and late （360-540 d） stages. By the end of the experiment （540 d）,the decomposition rate in treatments [N],[P],and CK had no significant difference,but was higher than that in treatment [N＋P] （P0.05）. Treatment [N] increased the litter N content,with the N immobilized at early stage but released later. Treatment [P] increased the litter P content,resulting in an increasing enrichment of P. Treatment[N＋P] increased the litter N and P contents,which were immobilized at early stage but released later. In all treatments,the litter C content showed a releasing trend. The relationships between the decomposition rate and the stoichiometric ratios of C,N,and P depended on decomposition stage. Our results suggested that the additive effect of elevated N deposition and P enrichment induced by urbanization could limit litter decomposition in urban forests.

关 键 词：碳氮磷化学计量比 凋落物分解 湿地松 城市化 

分 类 号：S714[农业科学—林学]