轮作对三七连作障碍的消减效应研究

Effects of Crop Rotation for Reducing Continuous Cropping Obstacles in Panaxnotoginseng Cultivation

通过田间移土试验,研究了轮作对三七连作障碍的消减效应,并分析了轮作对三七连作土壤微生物区系及理化性状的影响.结果发现:1随轮作年限的增加,三七的出苗率显著增加,轮作5年和7年土壤上所栽植三七的出苗率与新土上的无显著差异.2轮作使土壤中的放线菌数量增加,细菌数量略有下降,而真菌数量变化不大;土壤微生物的丰富度指数和物种多样性指数增加.3轮作后土壤中的N,P,K等主要养分含量有所降低,pH值降低,而有机质含量显著增加.轮作改善了三七连作土壤的微生物区系结构及理化性状,对三七连作障碍具有很好的消减作用.

In a field experiment, Panax notoginseng was cultivated on a new soil and on soils where crop rotation had been practiced successively for some years so as to investigate the effects of crop rotation for reducing continuous cropping obstacle of P. notoginseng, and the influences of crop rotation on microflora and the physical and chemical properties of the P. notoginseng-grown soils were analyzed. The results showed that with the increase in rotation farming years, P. notoginseng emergence rate improved significantly, and no significant difference existed between the 5- or 7-year rotation and planting on the new soil. Rotation increased the number of actinomycetes and slightly decreased the number of bacteria in the soil, while the number of fungi showed little change. Also, rotation increased soil microbial richness index and species diversity index. After rotation, the major nutrient contents in the soil like N, P and K decreased, pH was reduced, and organic matter content increased significantly. In conclusion, soil microbial commu- nity structure and soil physical and chemical properties were improved by crop rotation, which reduced continuous cropping obstacles of P. notoginseng obviously. Key words： Panax notoginseng; continuous cropping obstacle; crop rotation; soil microflora; soil physi cal-chemical properties