Study On Preparation And Effect Of Bacterial Fertilizer For Continuous Cropping Obstacle Soil Remediation

Continuous cropping obstacle is a common harmful phenomenon,which not only worsens the soil environment,but also leads to the increase of plant diseases and insect pests and the decline of crop quality.Bacterial fertilizer is a combination of biological control organisms and organic fertilizer,which can supplement the missing nutrient elements in continuous cropping obstacle soil,improve soil microbial community structure and enzyme activity,so as to repair or eliminate soil continuous cropping obstacle.In order to explore the remediation effect of bacterial fertilizer on continuous cropping obstacle soil,three kinds of solid bacterial fertilizer and three kinds of liquid bacterial fertilizer were prepared in this study.Green vegetables and spinach were used as test crops,and continuous cropping obstacle soil of green vegetables and spinach rotation for 8 years was used as test soil.Greenhouse and pot experiments were carried out to study the remediation effect of different bacterial fertilizer products on continuous cropping obstacle soil and crop growth.The main results are as follows(1)Three kinds of solid bacterial fertilizers were prepared: natural fermentation of solid organic fertilizer(G1),fermentation of solid organic fertilizer with lignocellulose degrading functional bacteria(G2),and fermentation of solid organic fertilizer with lignocellulose,starch and protein degrading functional bacteria(G3).In the process of solid bacterial fertilizer preparation,the compost temperature,total nitrogen content,total phosphorus content,total potassium content and seed germination index of G2 and G3 were significantly higher than G1,and reached compost maturity 10 days earlier than G1.At the same time,three kinds of liquid bacterial fertilizer were prepared: liquid organic fertilizer natural fermentation(Y1),liquid organic fertilizer inoculated with cellulose degradation functional bacteria fermentation(Y2),liquid organic fertilizer inoculated with cellulose degradation functional bacteria and nitrifying bacteria fermentation(Y3).The total nitrogen content of liquid bacterial fertilizer Y1,Y2 and Y3 were 798.58 mg / L,856.97 mg / L and 821.35 mg / L respectively,and the total phosphorus content was 152.72 mg / L and 165.48 mg / L respectively 14 mg / L,total potassium content was 28.47 mg / L,31.43 mg / L,29.56 mg / L respectively.(2)In the greenhouse experiment of solid bacterial fertilizer,compared with the control group GK without fertilization,the treatment groups of G1,G2 and G3 with solid bacterial fertilizer had significant improvement in soil physical and chemical properties,soil enzyme activities and culturable microorganisms,as well as the growth status of green vegetables and spinach.In the greenhouse experiment of green vegetables,compared with the application of solid bacterial fertilizer G1,the soil urease activity of G2 and G3 increased by 29.76% and 34.52%,the number of soil fungi decreased by 22.22% and 16.67%,and the fresh weight of green vegetables increased by 15.69% and 27.85%,respectively;in the greenhouse experiment of spinach,compared with the application of solid bacterial fertilizer G1,the soil available phosphorus content of G2 and G3 increased by 7.10% and 17.5%,respectively The number of bacteria increased by 25.00% and 41.67% respectively,and the fresh weight of spinach increased by 22.92% and 38.06% respectively.Solid bacterial fertilizer G2 and G3 produced by inoculating functional microorganism fermentation had a strong effect on improving soil properties of continuous cropping obstacles and promoting the growth of green vegetables and spinach.(3)In the pot experiment of liquid bacterial fertilizer,compared with the control group YK,the treatment groups of Y1,Y2 and Y3 had different degrees of improvement in soil enzyme activity,culturable microorganisms and the growth status of green vegetables and spinach.Compared with Y1,the soil urease activity of Y2 and Y3 increased by 21.82% and 25.45%,the number of soil bacteria increased by 44.44% and33.33%,and the fresh weight of green vegetables increased by 12.43% and 18.96%,respectively.Compared with Y1,the soil available phosphorus content of Y2 and Y3 increased by 10.14% and 6.82%,respectively The number of fungi decreased by29.17% and 37.50% respectively,and the fresh weight of spinach increased by 22.61%and 29.17% respectively.The liquid bacterial fertilizer Y2 and Y3 produced by inoculating functional microorganism fermentation had better effect in improving soil enzyme activity,improving soil microbial population structure and promoting the growth of green vegetables and spinach.(4)After applying bacterial fertilizer,the physical,chemical and biological structure and properties of continuous cropping obstacle soil were greatly improved,no matter whether it was liquid or solid bacterial fertilizer,whether it was in greenhouse or potted conditions,which indicated that bacterial fertilizer played an important role in the remediation of continuous cropping obstacle soil.The main reason may be that the added functional microorganisms can fully degrade the residual organic matter in the soil.On the one hand,it can eliminate the foundation for the survival of soil pathogenic microorganisms,improve the soil structure and properties,and promote the absorption of nutrients in the soil by crop roots.In addition,the growth and reproduction of dominant microbial populations also inhibited the growth of pathogenic microorganisms.It is necessary to further study the remediation mechanism of bacterial fertilizer products on continuous cropping obstacle soil.