%A CHEN Jie,GUO Tian-Wen,TAN Xue-Lian,ZHU Wei-Bing,WEI Xiao-Li,WANG Dong-Sheng,XUE Quan-Hong %T Comparison of Microecological Characterization in Rhizosphere Soil between Healthy and Un-healthy Plants in Continuous Cropping Potato Fields %0 Journal Article %D 2013 %J Acta Agronomica Sinica %R 10.3724/SP.J.1006.2013.02055 %P 2055-2064 %V 39 %N 11 %U {https://zwxb.chinacrops.org/CN/abstract/article_5517.shtml} %8 2013-11-12 %X
To explore the microecological mechanism of healthy plant growth in continuous potato fields in Gansu Province, China, we measured contents of available soil nitrogen (NH4+-N), phosphorus (P), and potassium (K) using conventional soil nutrient analytic methods, abundance of soil actinomycetes using serial dilution and plating techniques, and screened antagonistic actinomycetes from obtained actinomycete isolates using the agar block method. The selected dominant actinomycetes were identified by 16S rRNA sequence analysis, and the inhibitory effect of one dominant actinomycete, Streptomyces gancidicus, was tested using culture filtrate. Results showed that in the four-year continuous potato field, available soil P and K contents in the rhizosphere of diseased plants were respectively 29.9% and 12.5% lower than those of healthy plants, whereas soilNH4+-N content in the rhizosphere of diseased plant was 24.1% higher than that of healthy plant. Compared with those fromthe rhizosphere of healthy plants, the number of soil actinomycetes, Micromonospora, and unidentified actinomycetes from the rhizosphere of diseased plants cultured with the Gause1 medium decreased by 51.1%, 83.0%, and 53.9%, respectively, whereas the number of soil actinomycetes and Streptomyces from the rhizosphere of diseased plants cultured with the Humic Acid medium decreased by 46.0% and 46.7%, respectively. The soil actinomycetes antagonistic potentiality (SAAP) of actinomycetes with antagonistic effects on thefour pathogenic fungi of potato were lower in the rhizosphere of diseased plants than in the rhizosphere of healthy plants. S. gancidicus and S. galilaeus were found dominant in the rhizosphere of healthy and diseased plants, respectively. In conclusion, the microecology of rhizosphere soil that supports healthy plant growth in the continuous potato field is mainly characterized by: available nutrient combination of abundant P and K with relatively poor N contents; and a larger number of soil actinomycetes than that of diseased plants, with the numerically dominant actinomycetes showing beneficial antagonistic effect on several common soil-borne pathogenic fungi.