【作者】 庄海峰；

【导师】 王政权；

【作者基本信息】 东北林业大学 ， 森林培育， 2010， 硕士

【摘要】 土壤动物是土壤养分的主要制造者,数量众多的土壤动物通过土壤食物网控制土壤养分释放和碳(C)的积累,在森林生态系统能量流动和物质循环过程中发挥重要作用。本研究在中国北方落叶松(Larix gmelinii)和水曲柳(Fraxinus mandshurica)人工林采用土钻法研究施氮(N)肥对土壤动物数量、类群数、食性和多样性的影响；通过施杀虫剂处理以及内生长法研究土壤动物对总根长和根长密度的影响。得到如下结论：(1)落叶松人工林土壤动物密度平均26.1个×103／m2,隶属8纲13目34科；水曲柳人工林为31.6个×103／m2,隶属8纲15目43科。两林地土壤动物数量季节分布均为秋季(10月)>春季(5月)>夏季(7月),类群的季节分布均为秋季(10月)>夏季(7月)>春季(5月)。土壤动物密度和类群数随着土层深度的增加显著降低(P<0.05)。两林地中腐食性土壤动物均处于主导地位(占80%以上),植食性土壤动物次之(10%左右),捕食性土壤动物所占的比例最低(5%以下)。(2)两林地中土壤动物密度与土壤温度显著负相关(P<0.05)，而与土壤pH值和有机质含量呈显著正相关性(P<0.01)。施N肥导致土壤动物密度与土壤温度、pH值和有机质含量的相关性均下降。两林地中土壤湿度与土壤动物密度均不相关,施N肥后仅在水曲柳样地土壤10-20cm层显著相关(P<0.05)。(3)施N肥使落叶松林地土壤动物多样性指数和均匀度指数增加,而水曲柳林地降低。施N肥使落叶松林地土壤动物优势度指数降低,而水曲柳林地增加。施N肥导致土壤动物的各项多样性指数的季节分布规律发生显著变化,且三个指数在两林地中的变化不一致(P<0.05)。(4)在四个取样期和不同土层间,施N肥导致土壤动物的数量和类群数呈先增加后降低的趋势。施N肥导致落叶松和水曲柳样地腐食性土壤动物数量显著降低,植食性土壤动物数量显著增多,捕食性土壤动物数量变化不明显。(5)施杀虫剂处理使落叶松林地土壤0.10 cm层和10-20 cm层土壤动物数量分别降低97%和100%,水曲柳林地分别降低94%和84%。土壤动物数量的减少导致落叶松和水曲柳林地总根长和各根序根长密度显著增加(P<0.05),说明土壤动物影响根系的生产量,从而影响森林生态系统C循环。更多还原

【Abstract】 Soil fauna, which are main soil nutrition contributors, play an important role in soil carbon (C) and nutrient cycling in forest ecosystems. Soil fauna are sensitive to soil nutrients availability, but few studies focused on the interrelations between soil fauna density and nitrogen (N) availability in Northern forests. In this study, we used soil cores to study the effects of N addition on soil fauna densities, feeding habits and groups diversities in larch (Larix gmelinii) and ash (Fraxinus mandshurica) plantations, and used insecticide together with ingrowth cores to study the effects of soil fauna on root length density. The main results were below:(1) Soil fauna density in larch plantation was 26.1×103 ind m-2, which was belong to 8 classes,13 orders and 34 families. The corresponding values in ash plantation were 31.6×103 ind m-2,8 classes,15 orders and 43 families, respectively. In both plantations, seasonal peak of soil fauna density was October>May>July, but fauna species was October>July>May. There were higher density and number of groups in topsoil layer (0-10 cm) than that in subsoil layer (10-20 cm). Among the three feeding habits, the magnitude of soil saprophagous was accounted for over 80%, then the soil herbivores and predators were accounted for 10%and less than 5%, respectively.(2) The density of soil fauna had negative correlation with soil temperature (P<0.05), but positive correlation with soil pH and organic matte (P<0.01) in both plantations. However, N addition reduced these correlations. In contrast to other soil factors, soil moisture did not affect soil fauna densities, excepting in subsoil layer under the N treatment plots in ash plantation.(3) Diversity of soil fauna differed in plantations and treatments. Diversity index and evenness index in the N-addition plots were increased in larch plantation, but decreased in ash plantation comparing with the control plots. N addition also decreased the dominant index in larch plantation, but increased in ash plantation. These three indexes did change in seasonal patterns between the control and N-addition plots.(4) The effects of N addition on densities of soil fauna in both plantations differed among four sampling times in two soil depths, their densities was increased at the start time and decreased in latter time, so did fauna groups. In three feeding habits, the densities were decreased in soil saprophagous, increased in soil herbivores, and unchanged in soil predators after N fertilization.(5) Insecticide application significant reduced the densities of soil herbivores, with reduced by 97%(0-10 cm) and 100%(10-20 cm) in larch plantation, and reduced by 94%(0-10 cm) and 84%(10-20 cm) in ash plantation. The reduction of herbivore densities significant increased root length densities (P<0.05). These suggest that soil fauna, particularly soil herbivores, may be a critical in estimating soil C cycling in forest ecosystems.更多还原