| 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...
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