Abstract: 【Objective】 Nutrients and microbes are the two most important indicators for soil fertility and productivity. The aim of the experiment is to study the relationship between fertilizer application for high soil fertility and fungal disease of crops so the lands can be used sustainably. A long-term fertilizer location experiment of tobacco was carried out in Yunnan Tobacco Agriculture Research Institute. Soil samples were analyzed for understanding the relationship between fertilization method, soil fertility and crop fungus diseases, scientific fertilization for flue-cured tobacco, maintenance of long-term sustainable development of agricultural production can be realized. 【Method】 The influences of long-term fertilization on organic matter (OM), nutrients and microbial community structure were studied by routine analysis of phosphorus lipid fatty acids (PLFAs), and 454 pyrosequencing with a 16-year tobacco grown field trial. The experimental treatments included blank control (without fertilizers, CK), chemical fertilizer (CF), and mixture of organic manure plus chemical fertilizer (MCF). 【Result】 After 16 years of fertilization, OM increased by 19.63% and available phosphorus increased in MCF treatment, while in CF OM decreased by 20.56% and alkali-hydrolyzable nitrogen and potassium decreased in soil. Fertilization, particularly MCF, also increased the type and total amount of PLFAs, indicating the increment of microbial groups and numbers. In CF treatment, however, the PLFAs proportion of fungi, the heterotrophic microbes, was 2.52 folds compared with MCF and fungal groups (optimizing taxon units, OTUs) were increased by 25.91% compared with MCF. The diversity, evenness and predominance indexes showed a similar trend of that of fungal proportion and groups. The results suggested the changes in soil ecosystem environment by CF that was beneficial to fungal reproduction and growth, resulted in more fungal groups, high intensity, and obvious predominance. In soil fungus community, all of the fungi belonged to Ascomycota, Basidiomycota, Zygomycota, Chytridiomycota, and unidentified groups and most of them were Ascomycota. The abundance of the top 20 predominant fungi accounted for 33.01%-49.28%. Among them, 15 types existed simultaneously in soil in the treatments of MCF and CK, but only 6 in CF and CK. 【Conclusion】Therefore, a long-term chemical fertilization could be the reason for high fungal disease occurrence of crop but low organic matter in soil. Soil characteristics was one of the important factors for determining fungal communities, which could be changed slightly by MCF but greatly by CF for a long time.

Key words: long-term fertilization , soil nutrients , soil microbes , flue-cured tobacco