Continuous cropping obstacles of medicinal plants: Focus on the plant-soil-microbe interaction system in the rhizosphere

Continuous cropping obstacle (CCO) is a prevalent issue in agricultural development, particularly concerning medicinal plants. Medicinal plants can be used in part or in whole for medicinal purposes or as raw materials for the pharmaceutical industry. Approximately 70 % of medicinal plants rely on tubers to exert their therapeutic effects. CCO occurs within the rhizosphere of these plants and exhibits intricate plant-soil-microbe interactions. Root exudates release autotoxins that impact soil and microorganisms, leading to alterations in soil physical and chemical properties as well as microbial community structure. Consequently, there is an imbalance in soil nutrients and enzyme activity while beneficial microorganisms decrease, and pathogenic microorganisms increase. Soil and microbe factors react to plants, thereby affecting the quality and yield of medicinal plants. Currently, researchers are investigating the mechanisms underlying CCO in medicinal plants while developing strategies to effectively address this problem. This paper comprehensively analyzes existing literature to elucidate the interaction system among continuous cropping practices involving plants, soil, and microorganisms within the rhizosphere; it also integrates potential solutions for mitigating the impacts on both the pharmaceutical industry and the ecological environment.