Influence Of Fertilization And Cropping Pattern On Microbial Numbers And Bacteria Community Structures In Flue-cured Tobacco And Maize Soils

Tobacco and maize are the main cash and food crops, respectively, in China. They are widespread in Guizhou province and Southwest China. The production of tobacco and maize is very important for our sustainable development of economy and food supplies. Cropping and fertilization are the main measurement in agriculture, which affects directly the yields and qualities of crops and the health and characters of soils. Microorganisms are one of the components in soil ecosystems. They participate organic matter mineralization, nutrient mobilization and pathological microbial reproduction, which play important functions in soil fertility, crop growth and development, yield formation, and plant disease and pest control.The present experiment investigated the influence of cropping pattern and fertilization on microbial numbers and bacteria community structure in soils by normal culture and bio molecular technique in long-term fertilizer experiment sited in Guizhou Tobacco Research Academy. The main objective was to provide information on scientific cropping and fertilization, improved the health and qualities of soils, increased crop yield and qualities whereby to promote sustainable production of tobacco and maize.This experiment altogether establishesed8treatments, respectively be did not apply fertilizer, executed the nitrogenous fertilizer, executed the nitrogen+phosphate fertilizer, executed the nitrogen+potassium fertilizer, executed the NPK fertilizer, the NPK fertilizer+farm manure, as well as the NPK fertilizer+the biology organic fertilizer; Cropping pattern for flue-cured tobacco-maize crop rotation, flue-cured tobacco-flue-cured tobacco continuous cropping, and maize-maize continuous cropping. Following are the main results obtained.1. Through the traditional raise method of attributes, the research applies fertilizer differently treatments to the flue-cured tobacco and maize rhizosphere microbial quantity change rule, obtained in the flue-cured tobacco group time, vigorous and the mature period, organic inorganic matches fertilizer executed the soil rhizosphere bacteria and actinomyces quantity which (chemical fertilizer+farm manure or biology organic fertilizer) treatment was higher than other treatments; In the maize jointing stage, the big trumpet-shaped object time and the mature period, organic inorganic match fertilizer executed the soil rhizosphere bacteria quantity which (chemical fertilizer+farm manure or biology organic fertilizer) treatment also to be higher than other treatments; In the maize entire period of duration, the chemical fertilizer matches executed the biological organic fertilizer soil rhizosphere actinomycetes quantity to be higher than other treatments.2. Using the method of PCR-DGGE, the research applied fertilizer differently treatments to the flue-cured tobacco rhizosphere soil bacteria community structure influence rule, obtained transplants when the flue-cured tobacco, besides treatment which did not apply fertilizer, other treatments rhizosphere bacteria community structure difference was not obvious; After transplants, the rhizosphere bacteria community structure of the chemical fertilizer matches executes the farm manure to be obviously different with other treatments; And in the group stage and multi-topping stage, the rhizosphere bacteria community structure similarity of treatments that did not apply fertilizer and "the chemical fertilizer+farm manure" was high; After flue-cured tobacco mature, applied fertilizer had not obviously affected to the soil bacteria community structure.3. Using the method of PCR-DGGE, the research applied fertilizer differently treatments to the maize rhizosphere soil bacteria community structure influence rule, obtained before the maize harvest, the rhizosphere soil bacteria community structure of treatment which only executed the nitrogenous fertilizer and "the nitrogenous fertilizer+phosphate fertilizer" was similar, applied NPK fertilizer and "the chemical fertilizer +farm manure" treatment quite was also similar, indicated applied fertilizer in the maize vegetal period to the soil bacteria community structure had the significant difference. But after the maize harvest, applied fertilizer to the soil bacteria community structure had affected not obviously.4. Using the method of PCR-DGGE, studied two cropping pattern of the maize and the flue-cured tobacco rhizosphere soil bacteria community structure influence rule, obtained bacteria community structure of the maize rhizosphere soil in the maize-maize continuous cropping and in the flue-cured tobacco-maize crop rotation, was significantly different, bacteria DNA banding of the continuous cropping maize rhizosphere soil obviously was more than after the planter flue-cured tobacco of the maize soil; The bacteria community structure difference of flue-cured tobacco soil in the flue-cured tobacco-flue-cured tobacco continuous cropping and in the flue-cured tobacco-maize crop rotation, was small. In the flue-cured tobacco soil of flue-cured tobacco-maize crop rotation, the number of bacteria which certained DNA banding represents was richer.5. Under the different cropping patterns in the flue-cured tobacco and maize rhizosphere soil, the bacteria community structure overall were similar, but still had the slight difference, the short time cropping pattern was not big to the soil bacteria community structure influence, but the cropping pattern possibly accumulated to the soil bacterium community structure influence slightly.