【作者】 李云乐；

【导师】 乔玉辉； 孙振钧；

【作者基本信息】 中国农业大学 ， 生态学， 2005， 硕士

【摘要】 本研究作为“973”重大基础研究前期研究专项“大型人工生态反应器的探索性研究”的一部分,以农田生态系统为例,采用田间试验(2004.6～2004.10)和室内微宇宙模拟试验(2004.3～2005.3)相结合的方法,进行农田生态系统中有机物麦秸生物分解过程的研究和分析。 田间试验设置了堆肥区、化肥区、对照区和原貌区四种不同培肥处理和三种不同网孔的网袋处理。利用网袋法埋入农田土壤中,观察小麦秸秆在不同时期的分解情况,定期取样测定不同处理与有机物分解密切相关的几种主要土壤生物(微生物、原生动物、蚯蚓、线虫)的变化情况。 室内微宇宙模拟试验设置了三个不同处理:分别为堆肥(CFS)、对照不施肥(NFS)和原貌处理(OS)。将秸秆埋入上述三种处理的土中,定期取样,测定小麦秸秆的分解率以及土壤生物的变化情况。试验结果表明: 1.田间实验四种不同处理小麦秸秆分解率为堆肥区>原貌区>对照区>化肥区。不同网眼的网袋分解率为1cm>1mm>26μm。室内试验小麦秸秆最终的分解率为CFS>OS>NFS。 2.建立有机物分解指数模型,模型的拟合精度很高,表明采用本文中的非线性数学模型,可以很好地描述有机物分解的情况。 3.采用灰色关联分析,使有机物分解与环境、生物因素的关系量化和序化,进行比较和分析。对八种外界因素对于麦秸分解速率的影响进行研究。影响堆肥区麦秸分解速率的主要因素是土壤温度;影响原貌区麦秸分解速率的主要因素是土壤含水量、线虫、蚯蚓、全氮、有机质、土壤温度和微生物总量;影响化肥区的主要因素蚯蚓、全氮、土壤有机质、微生物总量、线虫;在对照区没有找到主要因素,所选因素均为次要因素。 4.田间实验蚯蚓总的数量为堆肥区>对照区>化肥区>原貌区。 5.田间实验线虫的数量顺序是化肥区>对照区>原貌区>堆肥区。各处理之间差异显著。化肥区线虫数量最丰富,平均分别比对照区、原貌区和堆肥区高出12.9%,31.8%和35.4%。三种网袋线虫总数平均值的次序是1cm>26μm>1mm。食细菌线虫是优势类群,占96.9%。室内实验线虫数量顺序是NFS>OS>CFS。 6.田间实验原生动物总丰富度顺序是堆肥区>原貌区>对照区>化肥区。三种不同网袋总的次序是1cm>26μm>1mm。实验中对土壤原生动物的三大类群:鞭毛虫、肉足虫和纤毛虫分别计数。数据结果显示:鞭毛虫数量占原生动物总数的69.0%,纤毛虫占20.4%,肉足虫占10.6%。鞭毛虫是原生动物的优势类群。室内实验原生动物总丰富度的次序是CFS>OS>NFS。 7.利用SIR法测定田间实验每克干物质秸秆的微生物呼吸总量,结果表明:堆肥区>原貌区>对照区>化肥区;碱液滴定法测定室内实验土壤呼吸速率,结果表明:CFS>NFS>OS,免耕比翻耕有少的呼吸量。同时发现呼吸速率的变化与微生物的变化有很密切的关系。 8.土壤生物并不是孤立存在的,各个类群间有着密切的关系。在小麦秸秆分解过程中,小麦秸秆组成成分的变化为土壤生物提供了不同的食物源和生境。在秸秆分解不同阶段,适应生境和食物源的土壤生物种类组成不同,导致了土壤生物群落的演替变化。更多还原

【Abstract】 This study is part of the pre-research of 973 Fundamental Research Project on "Large Manwork Ecological Reactor". Based on the agri-ecological combining field experiments and the micro-universe simulated experiments in laboratory, this research is to study the ecological process of organic matter decomposition in agri-ecosystem.There were four different fertilizer treatments in the experiment, including compost plot, chemical fertilizer plot, control plot and untilled natural plot. Before embedding into soil, the straw were packed with net packages of three different net sizes. Some indicators were regularly observed and recorded such as the decomposition of wheat staw, soil fauna and the environment conditions which were related to the decomposition of organic matter.The micro-universe simulated experiments in laboratory had set three treatments, including compost plot(CFS), control plot(NFS) and untilled natural plot(OS). The straw were embedding into the three different soil mentioned before, and sampled regularly to determine the decomposition of wheat staw and the changing situations of soil biology.The results of the experiments are as following:1. The decomposition rates of wheat straw between the four different soil fertility maintaining practices as the following descending trend: compost plot>untilled plot>control plot>chemical fertilization plot. The decomposition rates between net package of different net size have a descending trend of lcm>lmm>26μm. The decomposition rates of laboratory experiments have a descending trend of CFS>NFS>OS.2. A model of organic decomposition index has been built, which has a high simulated precision, it showed that the in-linearity mathematics model in the text can describe the decomposition condition of organic matter very well.3. The relationship between organic matter decomposition and environmental or biological elements were analyzed with gray relationship analysis method.. Soil temperature is the main element which influence the decomposition of compost plot most. The main influence elements of decomposition in untilled plot are soil moisture, nemotode, earthworm, total nitrogen, organic matter, soil temperature and total microorganism biomass. The main influence elements of decomposition in chemical fertilizer plot are earthworm, total nitrogen, soil organic matter, total microorganism biomass and nematodes . There was no main influence elements of decomposition in control plot, the selected elements were all subordination elements.4. The density of earthworm in field experiment have a descending trend of compost plot > control plot>chemical fertilization plot>untilled plot.5. The total quantities of nematodes in field experiment have a descending trend of chemical fertilization plot> control plot > untilled plot>compost plot. The difference between the treatments is obvious. The quantity of nematodes is highest in chemical fertilization plot, it is 12.9%, 31.8%, 35.4% higher than it of control plot, untilled natural plot and compost plot respectively. The average ofnematodes density in three kinds net package have a descending trend of 1cm>26μm>1mm. The bacteria-eating nematodes is the preponderant community on the surface of straw. The quantities of nematodes in laboratory experiment have a descending trend of CFS>NFS>OS.6. The abundance of protozoa in field experiments have a descending trend of compost plot > unfilled plot>control plot> chemical fertilization plot. And the different net package have a general descending trend of lcm>26μm>lmm. The quantitis of main protozoa community, includes flagellate, ameba and infusorian. The result of data show that flagellate, ameba and infusorian occupy 69.0%, 20.4 %, 10.6% of the protozoa community respectively. Flagellate is the preponderant community of protozoa. The general abundance of protozoa in laboratory experiment have a descending trend of CFS>OS>NFS.7. Using SIR measurement to determine the breath of dry mass, the result show that the breath of microbe has a obviously same law with the更多还原