Alleviation of vermicompost to obstacle in sterilized continuous cropping soil in strawberry production

【Objectives】 Soil sterilization has been used to deal with the disease obstacles caused by continuous cropping, however, this measurement also causes inhibition to the crop growth in the sterilized soils. Organic manures contain diverse bioactive components, especially bioactive vermicompost. So the effects of vermicompost and cattle manure were compared to provide a base for the choose of correct fertilizer source in strawberry production.【Methods】 Pot strawberry plants in greenhouse were chosen to conduct the experiments. Normal soil was collected from the soil below 20 cm depth in a grain field, and continuous cropping soil was from a strawberry garden where strawberry had been continuously grown for three years. All the two soils were divided into two parts, one part was sterilized and the other not. For the continuous cropping soil either sterilized or not, cattle compost or vermicompost, which was made by feeding earthworms with the cattle compost, was added in ratio of 20% of the soil separately, and NPK compound fertilizer was used as control. The growth of leaves and roots of strawberry plants in different growth stages was measured.【Results】Soil sterilization significantly(P＜0.05)suppressed the growth of roots, especially in seeding stagebefore flowering, and altered root architecture and ratio of shoot to root in all the monitored stages of strawberry plants. In the sterilized continuous cropping soil and normal soil, the addition of compound fertilizer significantly (P＜0.05) inhibited the development of root system, compared to the two compost treatments. There was no significant difference in total root length, root surface area, root tips and root forks between vermicompost and cattle compost treatments in continuous cropping soil, but those in vermicompost treatment were significantly higher than in cattle manure treatment in sterilized continuous cropping soil (P＜0.05).【Conclusions】 Vermicompost shows higher bioactivity than cattle manure in sterilized soils. In sterilized soils, application of vermicompost could significantly stimulate the growth of root system, and form larger shoot and root biomass and good root system of strawberry. So, the application of vermicompost should be recommended for the alleviation of continuous cropping obstacles in strawberry production.