不同茬口对当归根际微生物数量和产量的影响

目的 研究当归正茬、迎茬、重茬和三茬4个不同茬口对根际土壤主要微生物类群、产量及麻口病出成率的影响.方法 对不同茬口根际土壤采用稀释平板法进行微生物培养,细菌用牛肉膏蛋白胨琼脂培养基,真菌用马丁氏培养基,放线菌用改良高氏1号培养基.结果 迎茬、重茬和三茬根际土壤中的细菌数量分别比正茬降低了15.76%、30.67%和34.24%,真菌分别比正茬增加了24.73%、119.28%和135.77%,微生物多样性指数分别比正茬降低了47.90%、78.84%和80.63%,当归总产量分别比正茬下降了10.59%、29.52%和57.85%,麻口病出成率分别是正茬的1.37、2.52和4.12倍.结论 随着连作年限增加,土壤可培养微生物总数减少,其中细菌和放线菌数量减少,真菌数量明显增加,对连作表现出较高的敏感性,微生物多样性指数明显减小,当归一等归出成率和总产量明显下降,而三等及等外当归出成率及麻口病出成率显著增加.

Effect of various rotation systems on yield of Angelica sinensis and microbial populations in its rhizosphere

Objective To study the effects of four rotation system on the soil microbial populations in rhizosphere, yield, and recovery rate of Ditylenchus destructor of Angelica sinensis. Methods In rhizosphere soil, the microbe amount of various rotation system was determined with the flat dilution, the bacteria were counted with the culture medium of beef-cream and peptone, the fungi were counted with the Martin culture medium, the actinomyces was counted with the improved Gao 1 culture medium. Results Compared with the rotation cropping, the bacterium amount of companion, continuous, and 3a cropping was decreased by 15.76%, 30. 67%, and 34. 24%, respectively; The fungi amount was increased by 24.73%, 119.28%, and 135.77%; The diversity indexes of microbe were decreased by 47.90%, 78.84%, and 80. 63%, and the yields of A. sinensis were decreased by 10. 59%, 29.52%, and 57.85% The recovery rate of D. destructor was 1.37, 2.52, and 4.12 times. Conclusion The total microbes, which could be cultured in soil, will be decreased. The amount of bacterium, actinomycetes, diversity index and yields, recovery rate of the first grade of A. sinensis were decreased, while fungi and recovery rate of the third grade and substandard of A. sinensis, recovery rate of D. destructor increased with the continuous cropping increasing.