马铃薯连作田土壤中主要病原真菌的种群动态变化规律

Population dynamics of main fungal pathogens in soil of continuously cropped potato

作物长期连作后出现土壤肥力不平衡,病原物种类及其数量不断累积,表现出严重的连作障碍。连作障碍影响马铃薯的产量和品质,已成为马铃薯产业发展的主要限制因素,土壤微生物作为连作障碍的主要因素之一,研究土壤中病原菌种群动态变化具有重要的意义。为了深入研究土传病原真菌与马铃薯连作的关系,探明马铃薯连作障碍的机理,采用稀释平板法和残渣分离法研究了马铃薯连作对土壤病原真菌种群动态变化的影响。结果表明,甘肃省定西市渭源县会川镇半阴坡村马铃薯的主要土传病原真菌为镰孢菌、轮枝菌和立枯丝核菌;3种病菌主要分布于0～10cm土壤层,10～20和20～30cm土壤层则较少,其中0～10cm土壤层中每克土壤中的菌落数均随连作年限的增加而增加,镰孢菌(Fusariumspp.)为3 900,900,2 100和5 900个/g土,轮枝菌(Verticilliumspp.)为200,400,600和1 600个/g土,立枯丝核菌(Rhizoctonia solani)为7.80,9.58,20.60和22.40个/10g土;建议通过翻耕或药剂处理重点防治表层土传病菌。

Soil fertility imbalance, the pathogenic species and numbers accumulation were becoming obvious af- ter a Long term continous cropping of crops, which showed continuous cropping obstacle. Continuous cropping obstacle was one of the main restriction factors in potato industry. In order to understand the relationship between soil-borne fungal pathogens and potato continuous cropping, and explore the mechanisms of potato＇s continuous cropping obstacle, population dynamics of main fungal pathogens in soil was conducted by dilution plate and debris separation methods. The main fungi groups were Fusariurn spp. , Verticillium spp. and Rhi zoctonia solalti in soil of Huichuan in Gansu province, three fungal pathogens were maily distributed in 0-10 cm soil, with lessly in 10-20 cm and 20-30 cm soil. And the increasing year o the numbers of fungal pathogens in 0-10 cm soil increased obviously, among f pot whic ato ＇ s continuous cropping, h the number of Fusarium spp. in 0-10 cm at potato-bean stubble, potato continuous cropping one year, two years and three years were 3 900, 900, 2 100 and 5 900 per gram soil, numbers of Verticillium spp. were 200, 400, 600 and 1 600 per gram soil, respectively, And Rhizoctonia solani were 7.80, 9.58, 20.60 and 22.40 per ten gram soil. The results suggested that focus on control fungal pathogens in surface soil by ploughing or chemical treatments.