Effect of Biochar Composite Super Absorbent Polymers Combined with Arbuscular Mycorrhizal Fungi on Tobacco Growth and Soil Microenvironment under Drought Stress

GUO Xiaoqin; LI Qinkui; WU Guangpeng; ZHANG Xiaoquan

doi:10.15933/j.cnki.1004-3268.2026.01.008

Abstract：Through pot experiments,the effects of the dosage of biochar composite super absorbent polymers(SAP)(0,2,4,8 g/pot,denoted as S0,S1,S2,S3)and inoculation with arbuscular mycorrhizal fungi[Claroideoglomus etunicatum(CE),Glomus versiforme(GV),Funneliformes mossae(FM)and non inoculation control(CK)]on the growth,root configuration parameters,and soil microenvironment of Yuyan 5 tobacco under drought stress were investigated.The results showed that under drought stress,the SAP could promote the infection of arbuscular mycorrhizal fungi(AMF)on tobacco roots and had a positive effect on the mycorrhizal effect.The mycorrhizal infection rate was the highest(53.0%)and the number of vesicles was the highest(15.3 vesicles/cm)under the SAP dosage S2 treatment inoculated with FM.Under the same AMF inoculation treatment,with the increase of SAP dosage,tobacco growth indicators and soil physicochemical indicators(except for soil fungi,0.25-0.5mm,and<0.25 mm soil aggregate content)showed a trend of first increasing and then decreasing,and reached their peak under the S2 SAP dosage treatment.Under the treatment of S2 SAP,compared to the treatment without adding SAP or inoculating with AMF,the total length,total projected area,total volume,root tip number,and root vitality of tobacco roots treated with FM increased by 78.7%,130.1%,141.0%,44.7%,and 83.9%,respectively.The number of soil fungi decreased by 73.7%,and the content of bacteria and actinomycetes increased by 134.8%and 190.7%,respectively.Under drought stress,inoculation with AMF treatment could increase the activities of urease,cellulase,acid protease,acid phosphatase,sucrase,and chitinase in tobacco root soil to varying degrees.Compared to the treatment without adding SAP or inoculating with AMF,the FM treatment under S2 dosage increased the activities of urease,cellulase,acid protease,acid phosphatase,sucrase and chitinase activity in tobacco soil by 120.6%,94.9%,75.0%,200.0%,55.9%and 75.0%,respectively.In addition,inoculation with AMF treatment could increase the total nitrogen,available phosphorus,available potassium,and organic matter content of tobacco rhizosphere soil to varying degrees,and increase the soil aggregate content of tobacco roots(>2 mm and 0.5-2 mm).There was no significant change in the soil aggregate content of 0.25-0.5 mm,but it reduced the soil aggregate content of<0.25 mm.In summary,biochar composite SAP has a positive effect on plants,which can increase tobacco biomass,promote AMF infection,and enhance the positive effect of AMF on tobacco growth and drought resistance to a certain extent.Among them,the best effect on tobacco drought resistance is achieved when the SAP dosage is 4 g/pot(S2)combined with FM.