Effects of Biochar on Mango Root Growth, Soil Nutrients and Microbial Communities

PurposeTo study the effects of biochar on the soil nutrient content, root growth and soil microbial community structure of the mango root layer, providing a theoretical reference for the scientific application of biochar in orchards.

MethodsTaking the “Tainung No.1” mango as the research object, three treatments were set up: conventional fertilization (CK), conventional fertilization with 3% biochar (BC), integrated water and fertilizer application with 3% biochar (FBC), to analyze soil nutrients and the changes in root configuration, and Illumina Miseq sequencing technology was used to compare the differences in soil bacterial and fungal communities.

ResultsCompared with CK, soil pH and organic matter content of BC and FBC treatments increased; the contents of soil alkaline hydrolyzable nitrogen and available phosphorus of BC treatments increased significantly in fruiting period, and the contents of soil available potassium of BC and FBC treatments increased significantly in flowering period. The root weight density and root length density of BC treatment in fruiting period increased significantly, and the difference in average root diameter was not significant. The root box dimension was BC>FBC>CK. BC treatment increased the number, abundance and diversity of soil bacterial species, but it reduced the diversity of soil fungi; FBC treatment reduced the abundance and diversity of bacteria. BC and FBC treatments increased the abundance of Proteobacteria, Firmicutes, Gemmatimonadetes and Basidiomycota, the abundance of Chloroflexi and Ascomycota was reduced; Gemmatimonas, Sphingomonas and Mizugakiibacter were significantly enriched in BC treatment, Bacillus, Acidibacter, Alternaria and Penicillium were significantly enriched in FBC treatment. The result of redundancy analysis showed that the contents of organic matter, alkaline hydrolyzable nitrogen and available phosphorus were the driving factors of soil bacterial and fungal community structure changes, pH was the driving factor of fungal community structure changes, and root growth and development were regulated by soil environmental factors.

ConclusionAdding biochar is beneficial to improving soil nutrient availability in mango orchards, improving soil microbial environment and promoting root growth.