Abstract
Biochar is a new eco-material with the potential to control soilborne diseases. This study explored the relationship between the rhizosphere fungal community and the suppression of Phytophthora blight of pepper in the context of time after biochar application. A pot experiment was conducted and rhizosphere soils were sampled to determine the biochar-induced soil chemical properties, fungal community composition, and abundance of biocontrol fungi. The biochar-enriched fungal strains were screened by the selective isolation method, and their control effects against Phytophthora blight of pepper were determined using a pot experiment. Biochar treatments effectively inhibited pathogen growth and controlled the disease, with biochar applied immediately before planting (BC0) having greater effects than that applied 20 days before planting (BC20). Compared to the control, biochar-amended rhizosphere soils had a higher pH, available nutrient content, and fungal richness and diversity. Moreover, biochar treatments significantly increased the abundance of potential biocontrol fungi. The proliferation in BC0 was stronger as compared to that in BC20. Several strains belonging to Aspergillus, Chaetomium, and Trichoderma, which were enriched by biochar amendment, demonstrated effective control of Phytophthora blight of pepper. Canonical correspondence and Pearson’s correlation analysis showed that a high content of soil-available nutrients in biochar treatments was favorable to the proliferation of beneficial fungi, which was negatively correlated with both the abundance of Phytophthora capsici and disease severity. In conclusion, biochar-mediated improvement in the fungal community suppressed the Phytophthora blight of pepper. The biochar application time had a great impact on the control effect, possibly due to the short-term proliferative effect of the biochar on biocontrol fungi.
Highlights
Biochar, the solid by-product of biomass pyrolysis, features stable aromatic carbon structures, large surface areas, and high contents of certain nutrients and organic carbon (Sohi et al, 2010; Lehmann et al, 2011)
The disease indices of BC0 and BC20 on day 15 were reduced by 91 and 72%. Compared to those of CK, and those on day 45 were reduced by 63 and 35%, respectively. This suggested that biochar amendment reduced disease development and that the control effect of BC0 was stronger than that of BC20
Biochar demonstrated its possibility as a control agent against Phytophthora blight of pepper, supporting similar control effects of soilborne diseases observed in previous studies (Jaiswal et al, 2017; Zhang et al, 2017; Gao et al, 2019; Jaiswal et al, 2019; Chen et al, 2020)
Summary
The solid by-product of biomass pyrolysis, features stable aromatic carbon structures, large surface areas, and high contents of certain nutrients and organic carbon (Sohi et al, 2010; Lehmann et al, 2011). Recent studies have shown that biochar application can effectively control soilborne plant diseases caused by pathogenic fungi and bacteria, such as Fusarium oxysporum, Rhizoctonia solani, and Ralstonia solanacearum (Jaiswal et al, 2014, 2015; Elmer, 2016; Zhang et al, 2017; Gao et al, 2019; Chen et al, 2020). Our previous study first reported that the addition of biochar to soil resulted in a good control effect of Phytophthora blight of pepper, caused by the pathogenic oomycete Phytophthora capsici L. Biochar-induced soil chemical properties are closely associated with the control of diseases caused by soilborne bacteria (Zhang et al, 2017; Gao et al, 2019; Chen et al, 2020), but whether it is conducive to the control of diseases caused by oomycetes needs to be explored
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
