Variation Of Rhizosphere Soil On Continues Cropping Atractvlodes Macrocevhala And Alleviation For A.macroceyhala Cropping Obstacles Through Different Kinds Of PGPR Fertilizer

Atractylodes macrocephala Koidz., a kind of perennial medicinal herb, which accounts fora large share in Chinese traditional medicine market, belongs to Compositae genus.A.macrocephala can be of anti-inflammatory and antibacterial, be benefit to spleen andstomach and inhibit tumor. A.macrocephala is widely cultivated along Yangtze River, and isplanted in large scale in province Zhejiang, Anhui, Jiangsu, Hunan, Hubei, Sichuan, Chongqing;A.macrocephala from Pan an in Zhejiang is the most famous and previous. A.macrocephalahas serious continuous cropping obstacles with the problem that the soil must be fallowed for3~5a before replanting. Relying on routine rotation methods can not meet market demand, soA.macrocephala often face cropping due to limited land resources in main producing areas.However, A.macrocephala is easier to infect diseases and has higher death rate duringcontinuous cropping, which will bring bad influences on sustainable development. So far, thecause A.macrocephala cropping obstacles is not clear, and farmers tend to use a lot ofpesticides and fertilizers to improve growth conditions,but this will reduce the medicinal valueof A.macrocephala, and have a negative impact on the ecological environment.In this paper, soil pH, Nutrients and metals,enzyme activity and microflora in rhizospheresoil planted with A.macrocephala for different years were determined and the relationshipbetween cropping obstacles and changes in soil properties,soil microbial were discussed.Meanwhile, through laboratory and field experiment, the function of promoting growth anddisease suppressed of PGPR bacterial fertilizer unigrow sail canditiane, ATCC39169, E~2001to A.macrocephala were analysised and evaluated and select PGPR bacterial fertilizer whichhas the best effect to alleviate continuous cropping obstacle on A.macrocephala.The results areas follows:(1) Analysis of rhizosphere soil factors in continuous cropping A.macrocephala with increasing of planting years (0,1and2a) of A.macrocephala, pH value inrhizosphere soil decreases significantly, contents of organic matter and total N in rhizospheresoil appear the trend of firstly increasing and then decreasing, but available K content increasesgradually. And contents of available Fe, available Al and exchangeable Mn in rhizosphere soilincrease significantly or extremely significantly with the percentage of127.51%,18.38%and106.83%, respectively compared with the control. The activities of catalase, urease andprotease in rhizosphere soil planted with A. macrocephala for two years decrease significantlythan those of the control. The numbers of bacteria, actinomycetes and total microorganism inrhizosphere soil planted with A.macrocephala for two years decrease significantly but thenumber of fungi increases significantly than those in rhizosphere soil planted with A.macrocephala for one year.(2) external antagonis ability and promotion ability of PGPR bacterialSeparate single strong bacteria strain from different PGPR and test antagonism ability onFusarium oxysporum and S.rolfsii of different PGPR strains. Found that ATCC39169only hasinhibitory for F.oxysporum and has no antagonism ability not S.rolfsii, while other strains wereagainst of F.oxysporum and S.rolfsii. The antagonism ability of PGPR rankings for Youbei>E~2001> unigrow sail canditiane> ATCC39169. Results of IAA production of PGPR strainsshow that the ability of IAA rankings for ATCC39169> Youbei>unigrow sail canditiane>E~2001.(3) Effect of growth promotion and diseases prevention of PGPR fertilizerPGPR fertilizer could promote seedling height, ground diameter, fresh weight, dry weight,also could increase the net photosynthetic rate and chlorophyll content, improve POD enzymeactivity and reduce MDA content, enhance the vitality of root system, but these effects wereweakened gradually with the extension of time of continuous cropping. The effect of PGPRfertilizers also varied widely. ATCC39169had the best effect in early time, but obviouslyreduced in the late. Unigrow sail canditiane and Youbei had the similar trends of the effect tocontinuous cropping that from the early stage of the continuous cropping the effect is significantly higher than the late, but compared with other PGPR treatments, declineed moreslowly. Especially in the late seedling growth, seedlings treated with Youbei were better thanother processing. The growing effect of E~2001was lowest.