Response of Yam Yield and Soil Microbial Communities to Soil Fumigation and Substrate Cultivation

Soil fumigation is considered a method to control soil-borne diseases and solve crop continuous cropping obstacles. However, fumigant residues in the soil are detrimental to soil health. Though substrate cultivation is a cultivation mode that can promote plant growth, studies to date on whether substrate cultivation can replace soil fumigation for the control of soil pathogens are limited. In this study, the effects of chloropicrin fumigation (Pic) and substrate cultivation (SC) on yam growth, soil pathogens, soil nutrients, and microbial communities were demonstrated using a 2-year field experiment. The results showed that SC significantly increased the content of soil organic matter (SOM), available phosphorus, and available potassium compared with Pic. In addition, SC could effectively reduce the number of Fusarium spp. and Phytophthora spp., decrease the rate of diseased yam plants, and significantly increase the yam yield. Moreover, SC significantly increased the abundance of beneficial microorganisms such as Actinobacteriota, Acidobacteriota, and Bacillus in soil. Correlation analysis showed that yam yield exhibited a negative relation with the number of soil pathogens and a positive correlation with SOM. Our study suggests that substrate cultivation can be an alternative to soil fumigation to control soil pathogens and protect soil health.