Bio-diversity And Responses Of Soil Nematodes On Long-term Fertilization In Brown Soil Area

The research depended on the long-term fertilizers experiment on Brown soil in Shenyang. And the diversity of soil nematodes in crop fields was inspected and analyzed by treated with different long-term fertilizers in northeast China. The specific results were as follows:1. Identification of the soil nematodes around crop rhizosphere In the thesis, there were 285 samples being collected from the soil around crop roots in Shengyang City of Liaoning province. We identified 19 families 34 genus of soil nematodes, including 10 families 16 genus of plant nematodes and 9 families 18 genus of free-living nematodes through morphological taxonomy. The genus of plant parasitical nematodes were identified and drawn the picture. The genus name lists as fallow: Pratylenchus、Tylenchorhynchus、Helicotylenchus、Rotylenchus、Scutellonema、Pararotylenchus、 Criconemella、Aphelenchus、Aphelenchoides, Boleodorus、Malenchus、Rotylenchus and Filenchus. Many kinds of free-living and predatory-omnivorous nematodes as follow:Rhabditis、Protorhabditis、 Mesorhabditis、Pelodera、Cephalobus、Eucephalobus、Cervidellus、Acrobeloides、Longidorella、 Thonus、Epidorylaimus、Microdorylaimus、Mesodorylaimus、Aporcelaimus、Prismatolaimus、 Chronogaster、Mononchus and Mylonchulus.2. Response of soil nematodes on the Long-term fertilizers Based on the long-term experiment on brown soil, the impacts of long-term fertilizer application on distribution, community structure and seasonal changes of soil nematodes were studied. The results were as follows:Response of soil nematodes on Long-term Fertilizers in brown soil maize fields. We identified 16 families 28 genus of soil nematodes, including 9 families 13 genus of plant nematodes and 7 families 15 genus of free-living nematodes, of which Pratylenchus and Rhabditis were found to be the dominant genera. A large number of long-term organic manure fertilizer application could significantly increase the total amount of soil nematodes, improve bacteria-feeding nematodes abundance, inhibit plant parasitic nematodes abundance; secondly balanced application of NPK fertilizer was also conducive to the formation of soil nematodes relatively healthy and diverse ecological communities, while nitrogen fertilizer and no fertilizer CK destroy the ecological balance of the soil nematodes.Response of soil nematodes on Long-term Fertilizers in brown soil soybean fields. We identified 19 families 34 genus of soil nematodes, of which Helicotylenchus was the dominant genera, and Rhabditis was the sub-dominant genera. The most significant Long-term fertilization treatment effecting on soil nematodes was the high organic manure M2, the second is NPK, compared with no fertilizer CK. A significant increase in the number of all trophic groups of soil nematodes in M2 and NPK, and the abundance increased significantly too. Ecological indexes were significantly increased except dominance index λ and maturity index MI. The total nematodes, abundance of trophic groups and the Eco-index (except significantly higher λ and MI)were significantly reduced in the application of nitrogen fertilizer alone and no fertilization (CK) treatment, that mean the soil nematode diversity was destroyed. Relative abundance of soil nematodes total numbers and BF graphic had significant positive correlation to soil organic matter, available phosphorus and available potassium in the research, on the contrary, PP graphic had negative correlation. All the results showed that the long-term organic manure and balanced application of NPK fertilizer were more conducive to form a good ecological balance of soil nematodes.The community structure and Eco-index of soil nematodes in soybean and maize fields of long-term fertilization were compared under the corn-corn-soybean rotation system. The results showed that the soil nematodes in soybean fields was more abundance than that in the corn fields. Numbers of soil nematodes, changes of community structure and the index of ecological had proven that long-term fertilization of organic manure and balanced application of NPK fertilizer were more conducive to form a good ecological balance of soil nematodes.