Effects of the Continuous Cropping and Soilborne Diseases of Panax Ginseng C. A. Meyer on Rhizosphere Soil Physicochemical Properties, Enzyme Activities, and Microbial Communities

Abstract

Continuous cropping and soilborne diseases affect soil properties and soil microbial diversity and structure, which are the main factors posing obstacles to the continuous cropping of ginseng. This study explored the response of the physicochemical properties, enzyme activity, and microbial community of ginseng rhizosphere soil to continuous cropping and soilborne disease (root rot of ginseng). We used woodland soil without ginseng planting as a control to study these changes. The results showed that continuous cropping and soilborne disease significantly affected soil physicochemical properties, enzyme activities, and microbial communities. The levels of total nitrogen, hydrolyzable nitrogen, organic matter, and soil pH decreased significantly, while available phosphorus, available potassium, total phosphorus, and total potassium showed significant accumulation after continuous cropping. The activities of urease, catalase, sucrase, acid phosphatase, alkaline phosphatase, and polyphenol oxidase decreased significantly after continuous cropping. Using MiSeq high-throughput sequencing, we found that the alpha diversity and the number of bacterial and fungal communities significantly changed after continuous cropping and soilborne disease. A redundancy analysis suggests that soil physicochemical properties and enzyme activities also affect soil microbial communities. In summary, this study revealed the effects of continuous cropping and soilborne disease on soil and provides a theoretical basis for alleviating soilborne disease in ginseng.