| Biochar,as an emerging soil fertilization material,has demonstrated benefits for soil carbon pool,soil nutrient release,and soil biology in many studies.However,there is a lack of comparative studies between biochar and traditional soil fertilization materials(corn straw,pig manure compost),especially those supported by long-term localization trials.Therefore,this study was conducted to compare the long-term effects of biochar and traditional soil fertilization materials(corn straw,pig manure compost)on soil biological and non-biological factors.Two types of biochar utilization were selected,i.e.,direct application as a soil conditioner and application as a fertilizer slow-release multiplier,and two traditional soil fertilization materials,i.e.,corn straw and pig manure compost,were used as controls to set up a micro-zone trial in the field.The localization trial started in 2009 with four treatments: corn stover+ NPK(CS),pig manure compost + NPK(PMC),biochar + NPK(BIO)and biochar-based fertilizer(BF),with peanut as the crop.After 12 years of continuous application,the soil was collected from the 0-20 cm soil layer in 2020 before planting peanuts,and the conventional soil physicochemical indexes and soil agglomerate composition were measured.This study was conducted to clarify the differences in soil fertility and microbial communities between biochar and traditional organic fertilization methods and between the two methods of biochar utilization,and to provide theoretical references for revealing the mechanism of biochar fertilization of soil.The main results of the study are as follows.(1)Compared with the pre-test period,the long-term application of various organic materials with chemical fertilizers significantly increased soil p H,organic carbon,alkaline soluble nitrogen and effective phosphorus content.After 12 years of continuous application,biochar and charcoal-based fertilizers significantly reduced soil total nitrogen content but did not significantly change soil total phosphorus content compared to pig manure compost.Compared with the two conventional organic materials,the pig manure compost was more efficient in enhancing and improving the above indicators.The soil physicochemical properties of the biochar,charcoal-based fertilizer and corn stover treatments were more similar and most different from those of the pig manure compost application.(2)After 12 years of continuous application,biochar and charcoal-based fertilizer reduced soil fungal alpha diversity compared to traditional fertilization methods(corn stover and pig manure compost),and each formed a fungal community significantly different from the other treatments,with the greatest difference in soil fungal communities between the pig manure compost application and the other treatments.The application of biochar and charcoal-based fertilizer significantly reduced the relative abundance of the Stenotrophomonas phylum compared to the application of corn stover.The application of biochar significantly reduced the relative abundance of the phylum Peridiomycetes compared to the application of pig manure compost.The relative abundance of Fusarium and Fusicolla with biochar and charcoal-based fertilizer application was higher than that of CS treatment,while Acrophialophora,Guehomyces and Solicoccozyma were lower than that of CS treatment.The relative abundance of Auxarthron,Plectosphaerella and Gibberella with biochar application was higher than the other treatments.Soil MWD,p H and alkaline nitrogen content could better explain the variation in soil fungal composition at the phylum level.Soil MWD and alkaline nitrogen content could better explain the variation in fungal composition at the genus level.Application of charcoal-based fertilizer reduced the relative abundance of pathogenic fungi compared to corn stover,and increased the relative abundance of symbiotic fungi compared to corn stover and biochar.(3)After 12 years of continuous application,biochar and charcoal-based fertilizer reduced soil bacterial alpha diversity compared to traditional fertilization methods(corn stover and pig manure compost).The greatest difference in soil bacterial community was observed under biochar application compared to other treatments.Application of biochar significantly increased the relative abundance of Phylum Aspergillus,Phylum Bacillus and Sphingomonas,but significantly decreased the relative abundance of RB14 compared to the other treatments.Application of charcoal-based fertilizer significantly reduced the relative abundance of Gaiella compared to corn stover and significantly reduced the relative abundance of Bryobacter compared to pig manure compost.Soil p H,MWD,total nitrogen and alkaline nitrogen content could better explain the variation in soil bacterial composition at the phylum level.Soil organic carbon,p H and MWD could better explain the variation of soil bacterial composition at the genus level.In conclusion,biochar,whether applied directly or as a fertilizer slow-release booster,had a similar effect on soil fertility enhancement as corn stover,although it was not as good as pig manure compost.The application of biochar and charcoal-based fertilizers reduced soil fungal and bacterial alpha diversity compared to traditional fertilization methods(corn stover and pig manure compost).Soil fungal communities were less different between biochar and charcoal-based fertilizer application and corn stover application,and most different from pig manure compost application.The differences in soil fungal communities between the application of different organic materials were closely related to soil physicochemical properties,i.e.MWD,p H and alkaline nitrogen content.Charcoal-based fertilizer was able to optimize soil fungal composition,i.e.,reduce pathogenic fungi and increase symbiotic fungi.Soil bacterial communities differed most from other treatments with biochar application,and differences in soil bacterial communities with different organic materials were closely related to soil p H,MWD,organic carbon,and total nitrogen content. |
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