Study On The Pot Application Circumstance Of Strain BHC-A And It’s Effect In The Fields Of Hainan Area

Perisistent Organic Pollutants HCHs,with disabled more than 30 years,can be generally detected in field soils because of it’s refractory characteristics.It has been designated as determination standard of soil quality.Our pre-investigation results showed that some field soils had HCHs residues,with the potential risk to the safety of agicultural products.Strain BHC-A is an effective HCHs degradating bacteria,with a degrading rate of 100%in labortary conditions.To enlarge application range of BHC-A,as well as to explore a rapid pathway for HCHs removal from field soils in Hainan,pot and field experiments were conducted.The main research contents include(1)investigating favorable conditions for y-HCH microbial degradation by strain BHC-A in four typical soils in Hainan,and evaluating BHC-A application safety to soil microorganisms;(2)exploring if the stain is effective and environmental safe for HCHs degradation in field soils.The main experimental results were shown below.(1).Strain BHC-A was capable of degrading γ-HCH in four types of Hainan soil samples.From the principal factor analysis,four factors tested influence degradation rate ofγ-HCH,ranking as:soil types>soil temperature>inoculation concentrations>soil water content>stroma,the most favorable degrading conditions were:garvelly loam,30℃,inoculation concentrations of 20%(v/v,inocula/water),flooding,cassava dregs.(2).y-HCH inhibited soil microorganisms’ growth,and BHC-A can relieve the inhibitory effect.Variance analysis results indicated that BHC-A significantly facilitate the growth of bacterium and fungus in soils after 7-d incubation,and present significant difference compared with the control(P<0.01).While the influence of BHC-A on actinomycetes was minor.(3).Field experiments showed that HCHs residues was greatly decrease after BHC-A application in soils,and the degradation rate of α-HCH,β-HCH,γ-HCH and HCHs were 39.5%、19.4%、100%、45.4%,respectively,in which the degradation rate P-HCH was 13.9%lower than the control,May be due to sampling of cause,α-HCH,γ-HCH and HCHs improved 45.2%、114.3%、40.8%than the control.Meanwhile,BHC-A have impact on soil enzymes and microorganisms after application in soils.The concentrations of urease and catalase firstly increased and then decreased when appling BHC-A in the field soils.But the change trends of acid phosphatase and cellulase were similar with the control.After application of BHC-A in soils,the number of bacterium and fungum increased during the first 7 days of application,and decreased,no difference with the control at 27d.Therefore,it can be concluded that BHC-A inocula was effective to enhance HCHs degradation in soils,and there were no persistent effect on soil enzymes and microorganisms.