魔芋连作对根际土壤微生物数量及酶活性的影响

Effect of Long-term Continuous Cropping With Amorphophallus konjac on Rhizosphere Soil Microflora and Enzyme Activities

以未种魔芋、种植1年和种植14年的魔芋根际土壤为试材,采用稀释涂布平板法和土壤酶研究方法研究了连作对魔芋根际土壤微生物数量及5种酶活性的影响,以期为克服魔芋连作障碍提供参考依据。结果表明:长期连作会使魔芋根际土壤细菌数量呈增多,及真菌和放线菌数量呈减少的趋势,其中连作14年魔芋土壤与当年种植魔芋和未种魔芋空白土壤相比,土壤细菌数量分别增加28.6%和80.0%,真菌数量分别减少了32.1%和51.3%,放线菌数量分别减少了60.5%和70.0%;连作后土壤蛋白酶、过氧化氢酶和脲酶活性呈下降趋势,连作14年其酶活性分别较种植1年下降了67.3%、26.2%和23.0%,而酸性磷酸酶和多酚氧化酶活性有明显提高,分别增加了62.3%和37.0%。表明魔芋长期连作会对其根际微生物区系及土壤酶活性产生较大影响。

With the rhizosphere soil of Amorphophallus konjac was planted for 0,1,14 years as the test material,diluted coating plate method,soil enzyme research method were used to determine the number of soil microorganisms and the changes of five soil enzyme activities in the rhizosphere soil of Amorphophallus konjac after continuous cropping.This study aims to provide a theoretical basis for overcoming the continuous cropping obstacles Amorphophallus konjac.The results showed that with the continuous cropping of Amorphophallus konjac,the amount of bacteria in the rhizosphere soil of Amorphophallus konjacshowed an increasing trend,and the number of fungi and actinomycetes showed a decreasing trend.The soil of 14 cropping years of Amorphophallus konjac was compared with that the soil of cultivating Amorphophallus konjac in that year and the soil didn′t plant Amorphophallus konjac,the number of bacteria was increased by 28.6%and 80.0%respectively,the number of fungi was decreased by 32.1% and 51.3% respectively,and the number of actinomycete was decreased by 60.5%and 70.0% respectively.The activities of protease,catalase and urease in rhizosphere soil were inhibited by continuous cropping of Amorphophallus konjac,which decreased by67.3%,26.2%and 23.0%respectively compared with the soil planted for one year,but the activities of acid phosphatase and polyphenol oxidase were promoted,which increased by 62.3% and 37.0%respectively.All these indicated that the continuous cropping of Amorphophallus konjac would have a great impact on its rhizosphere microbial flora and soil enzyme activities.