Simple rain-shelter cultivation controls soilborne root-rot disease and improves the quality of Panax notoginseng

Abstract

Soilborne root-rot diseases are prevalent in agricultural production, significantly limiting the sustainable cultivation of Panax notoginseng (PN), a renowned medicinal plant in Asia. In this study, a field experiment was conducted to explore the efficacy and mechanisms of a newly designed rain-shelter cultivation method for managing soilborne root-rot diseases in PN. We conducted three treatments that included traditional cultivation (with fertilizer and pesticide), non-rain shelter cultivation (without fertilizer and pesticide), and simple rain-shelter cultivation (without fertilizer and pesticide). After three months of experimentation during the rainy season (July to September 2022), the photosynthetic characteristics, survival rate, root-rot incidence, yield, and saponin contents, including notoginsenoside R₁, ginsenoside Rd, ginsenoside Re, ginsenoside Rb₁, ginsenoside Rg₁, and ginsenoside Rg₂, of PN, were investigated. In addition, the soil properties and allelochemicals, including p-hydroxybenzoic acid, syringic acid, vanillic acid, p-coumaric acid, ferulic acid, and benzoic acid, and microbial communities were analyzed. The results showed that, compared with non-rain shelter cultivation, simple rain-shelter cultivation significantly promoted photosynthesis and reduced the root-rot incidence of PN (P < 0.05), which was similar to traditional cultivation; moreover, with the exception of ginsenoside Rb₁, other saponin contents in the roots increased by 6.1–85.8 % under rain-shelter cultivation. In addition, compared with non-rain shelter cultivation, the contents of water, NH₄⁺–N, and six allelochemicals in soil all decreased (P < 0.05), and the relative abundance of pathogenic Fusarium decreased by 49.1 %, while beneficial Trichoderma increased by 313.9 % (P < 0.05), alluding to the possible mechanisms of the reduced root-rot incidence of PN under rain-shelter cultivation. In summary, our study clearly showed that simple rain-shelter cultivation is an efficient strategy to control root-rot disease and improve the quality of P. notoginseng.