陈毅青 陈宗铸 陈小花 雷金睿 李苑菱 吴庭天

摘  要：为揭示热带沿海地区不同森林类型凋落物现存量及其养分元素储存能力的差异，选取林地相邻、生境条件基本一致的青皮林和木麻黄林为研究对象，设置随机样地，采集未分解层、半分解层、已分解层凋落物样品，测定凋落物层现存量和主要养分元素含量、储量及其释放率。结果表明：（1）木麻黄林凋落物层现存量为29.49 t/hm2，是青皮林的2倍，2种林型不同分解层表现为：已分解层>半分解层>未分解层;（2）2种林型不同分解层养分元素含量基本遵循C>N>Mg>K>P的变化模式，随着凋落物分解，青皮林各养分元素含量逐级降低，木麻黄林则因养分元素不同而异，可能因凋落物C含量流失过多出现损失速率大于分解释放养分速率而造成半分解层N、P、Mg的含量相对增加，但均在已分解层含量最低;（3）木麻黄林凋落物层养分储量值为8448.23 kg/hm2，是青皮林的2倍，各分解层凋落物养分元素的储量依次为C>N>Mg>K>P，与养分元素含量变化规律一致，而养分释放率从未分解层（?1.79%、?0.97%）到半分解层（0.65%、1.23%）呈现增加趋势。总之，同一立地条件下，不同林型的凋落物现存量、养分含量及其储量的差异可能与植物叶片生物学特征、微环境条件、微生物种群及活性不同有关。

关键词：凋落物层;养分元素;释放率;青皮林;木麻黄

中图分类号：S718.5      文献标识码：A

Stock and Nutrient Characteristics of Litter at Different Forest Types in the Southeast Coast of Hainan Island

CHEN Yiqing1，2，3， CHEN Zongzhu1，2，3*， CHEN Xiaohua1，2，3， LEI Jinrui1，2，3， LI Yuanling1，2，3， WU Tingtian1，2，3

1.Hainan Academy of Forestry （Hainan Academy of Mangrove）， Haikou， Hainan 571100， China; 2. Hainan Key Laboratory of Monitoring and Application of Tropical Forestry Resources （plan）， Haikou， Hainan 571100， China; 3. Haikou Wetland Protection Engineering Technology Research and Development Center， Haikou， Hainan 571100， China

Abstract： This paper aims to investigate the difference of the existing litter stock and nutrient element storage capacity of different forest types in tropical coastal areas. Selecting Casuarina equisetifolia forest and Vatica mangachapoi forest with almost the same habitat conditions in the Southeast coast of Hainan Island， permanent plots were established in each vegetation community. Litter samples were collected from un-decomposed layer litter， semi-decomposed layer litter and decomposed layers. The standing crop of litter， the main nutrient elements content， reserves and release rates were measured. The standing crop of litter in C. equisetifolia forest was 29.49 t/hm2， which was twice that of Vatica mangachapoi forest and different decomposition layers were in the order of decomposed layer>semi-decomposed layer> un-decomposed layer. The content of the main nutrients in litters layer and its different decomposed layers was in the order of C>N>Mg>K>P at the two types， with the decomposition of litter， the content of various nutrient elements in green forest decreased step by step， C. equisetifolia forest was different with different nutrient elements， but the content was the lowest in the decomposed litter layer. The loss rate of excessive loss of C content in litters was greater than the rate of decomposition and release of nutrients， resulting in the relative increase of N， P and Mg content in the semi-decomposition layer. The nutrient reserve value of litter layer in C. equisetifolia forest was 8448.23 kg/hm2， which was twice as much as that of Vatica mangachapoi forest， the storage of nutrient elements in litter layer followed the order of C>N>Mg>K>P， consistent with nutrient element content change rule. The nutrient release rate increased from the un-decomposed layer （?1.79%， ?0.97%） to the semi-decomposed layer （0.65%， 1.23%）. In summary， under the same habitat condition， the difference of litter stock， nutrient content and reserve in different forest types may be related to the biological characteristics of plant leaves， microenvironmental conditions， microbial population and activity.

Keywords： litter layer; nutrient element; release rate; Vatica mangachapoi forest; Casuarina equisetifolia

DOI： 10.3969/j.issn.1000-2561.2021.04.036

凋落物作为森林生态系统的重要组成部分[1]，对森林养分循环起着重要作用[2]，是陆地生态系统养分循环关键过程的重要组分[3]，是地上向地下传输营养物质的重要纽带[4]，亦是土壤肥力的重要来源[5]。研究表明，凋落物现存量是凋落物凋落量与分……