【作者】 何帆；

【导师】 王得祥；

【作者基本信息】 西北农林科技大学 ， 生态学， 2008， 硕士

【摘要】 森林凋落物是森林生态系统生产力构成的一部分,凋落物的分解是森林生态系统维持内部养分循环的主要途径,因此对生态系统功能的深入认识离不开对凋落物分解的研究。影响凋落物分解速率的因素主要包括环境因素和凋落物本身的性质:环境因素,包括凋落物所处地的气候因素以及生物因素的影响。气候变化会影响到温度、空气湿度以及降水等发生改变,水热条件直接影响凋落物分解过程中的淋溶作用和微生物活性,从而对凋落物分解动态产生显著影响,此外还通过影响凋落物质量、微生物和土壤动物的活动而间接调节凋落物的分解速率。凋落物自身的性质,也就是凋落物自身的化学及物理性质,外界条件一致的前提下,凋落物分解主要受到凋落物本身性质的支配。不同树种的凋落物因本身生物学性质的不同而出现差异性,因此凋落物在分解前的性质对分解过程有着非常重要的影响。凋落物的质量主要体现在两个方面,一个是凋落物的化学特征,如凋落物的各种元素,粗纤维、粗脂肪含量等。另一方面是指凋落物的物理特征,如凋落物的表面特征。本研究对秦岭林区不同海拔的华山松、油松、锐齿栎、华北落叶松四种林分凋落叶分解前的养分元素、有机成分和热值特征,及一年期间分解过程中的变化趋势进行系统测定和分析。研究得出以下结果:（1）分解前,四种凋落叶的粗纤维、粗脂肪含量和热值大小均为油松>华山松>华北落叶松>锐齿栎。养分元素中全氮和全磷含量大小为锐齿栎>华北落叶松>华山松>油松。油松、华山松、华北落叶松叶片凋落物的C/N、C/P、粗纤维/N均大于锐齿栎,差异性极显著（P<0.01）。油松的C/N、C/P、粗纤维/N均最高,分别为72.33、1311.28和36.98,是锐齿栎各项比值的1.9～2.5倍。四种树种的凋落叶性质存在差异,但海拔的变化对相同树种凋落叶的性质并没有显著的影响（P>0.05）。（2）在分解前期,几种凋落叶N、P的含量呈现上升趋势,增长范围分别为158.51 %～125.20%和185.13%～125.85%。与分解前凋落叶中的粗纤维含量相比,粗纤维相对含量分别增大104.64%、103.70%、121.85%和110.46%。而粗脂肪、有机碳含量和热值呈现出下降的趋势,下降范围分别为32.93～24.10g.kg^-1、26.30～68.50 g.kg^-1和4.15～2.78kJ.g ^-1。比较不同树种凋落叶在分解过程中各种成分的变化趋势,显示出在相似的环境条件下凋落叶的分解主要取决于本身的性质。（3）相同树种不同海拔的凋落叶在一年的分解过程中N、P、粗纤维和有机碳含量的变化并没有表现出显著的差异性（P>0.05）。而相同树种低海拔凋落叶的粗脂肪分解速率大于高海拔凋落叶的分解速率,且四种树种都表现出显著差异（P<0.01）。在一年的分解过程中华山松和油松的热值变化表现出显著性差异（P<0.05）,而华北落叶松和锐齿栎表现出极显著差异（P<0.01）。更多还原

【Abstract】 Forest litter is a part of the forest ecosystem productivity, the major nutrient cycling way of the forest ecosystem is the decomposition of forest litter, so the deep understanding of the ecosystem function can not be separated from the research of the decomposition of forest litter. The major impact factors of the litter decomposition rate are environmental factors and the own characters of the forest litter: the environmental factors, including the climatic factors and biological factors of the place where the forest litter was. Climate change will affect the temperature, air humidity and precipitation and other changes, hydrothermal conditions will directly impact the eluviation and the microbial activity during the litter decomposition, thus the dynamic of litter decomposition will be impacted significantly. In addition, the litter decomposition rate will be indirectly regulated through the impact of litter quality, soil microorganisms and animals activities. The own character of litter, that is the own chemical and physical properties of litter, when the environment condition is the same, the litter decomposition was controlled by its own character. Litter of different tree species are different because of their own biological character, so the character of litter before decomposition has very important influence on the decomposition process. The litter quality is reflected in two main aspects, one is the chemical characteristics of litter, such as the various elements of litter, crude fiber, fat content and so on. On the other hand refers to the physical characteristics of litter, such as the surface characteristics of litter.Nutrient element, organic matter and caloric value of litter leaf of Pinus armandii、Pinus tabulaeformis、Quercusaliena var. acu teserrata、Larix principis-rupprechtii in qinling forest area were studied. The results showed that:（1） Before decomposition, crude fiber, crude fat and caloric value of four kinds litter leaf all properly had the relationships of Pinus tabulaeformis > Pinus armandii > Larix principis-rupprechtii>Quercusaliena var. acu teserrata. Both total N and total P had the relationship of Quercusaliena var. acu teserrata > Larix principis-rupprechtii > Pinus armandii>Pinus tabulaeformis. C/N, C/P and crude fiber/N of Pinus tabu laeformis、Pinus armandii、Larix principis-rupprechtii were all higher than those of Quercusaliena var acu teserrata forest （P<0.01）, the highest was Pinus tabulaeformis forest, the ratios were 72.33, 1311.28 and 36.98, they were 1.9～2.5 times of Quercusaliena var. acu teserrata forest respectively. The quality of litter leaf of four tree species were different, but the change of elevation didn’t have significant influence on the quality of litter leaf in the same forest （P>0.05）.（2） The N and P content took on a rising trend in the early stage of decomposition, and the increasing ratios ranged from 158.51% to 125.20% and from 185.13% to 125.85%, respectively. The relative content of crude fiber increased 104.64%, 103.70%, 121.85% and 110.46% compared to that before decomposition, respectively. With the decomposition of emarcid leaf, the content of Crude fat, organic carbon and caloric value declined gradually, and the decrease ratios ranged from 32.93 to 24.10g·kg^-1 from 26.30 to 68.50g·kg^-1 and from to 4.15 to 2.78kJ·g-1, respectively. The comparison of the changing trends of the contents of all kinds of nutrients showed that the decomposition of emarcid leaf in different forest lied on its own character when the environment was the same.（3） During the one year decomposition of leaf litter of the same species at different altitudes, nitrogen, phosphorus, crude fiber and organic carbon contents showed no significant differences （P>0.05）. While the decomposition rate of leaf litter of the same tree species in low latitude was higher than the decomposition rate of leaf litter in high latitude, and the four tree species all had significant difference （P<0.01）. During the one year decomposition, the caloric value of both Pinus armandii and Pinus tabulaeformis had a significant change （P<0.05）,and the caloric value of Larix principis-rupprechtii and Quercusaliena var. acu teserrata had a best significant difference （P<0.01）.更多还原