Field Application Effect Of Bioremediation Fertilizer For Atrazine And Clomazone Residual In Soil

Atrazine and clomazone are excellent herbicides used in maize and soybean fields in Heilongjiang Province,respectively.However,due to their long residual time in soil and their perennial application,it is difficult to degrade and eliminate the accumulation in the soil relying on the self repairing ability of soil,so they cause serious toxicity to sensitive crops after rotation.In order to change this grim situation,microbial remediation has become a research hotspots because of its safety,efficiency and maneuverability.In order to further explore the feasibility of the practical application of long residue herbicide bioremediation bacterial fertilizer in the field,field experiment and frame planting test were conducted in Hongguang township of Jiayin county and the screenhouse of Northeast Agricultural University.The bioremediation bacterial fertilizer was applied to the plots where atrazine and isoxazine were applied in the previous crop.Dry direct seeding of rice was carried out in atrazine residue soil,and coriander and spinach were sowed in the clomazone residue soil respectively.The effects of different application methods of bioremediation bacterial fertilizer on herbicide residues and soil enzyme activity in soil,growth physiological indexes and yield of the sensitive crop were studied.The main results are as follows:(1)Different application methods of atrazine bioremediation bacterial fertilizer had remediation effects on dry direct seeding rice.1)Atrazine bioremediation bacterial fertilizer can restore the chlorophyll content of rice leaves.The chlorophyll content of rice increased significantly after applying bacterial fertilizer.2)Atrazine bioremediation bacterial fertilizer can improve the activities of antioxidant enzymes in rice leaves.The activities of POD and SOD in rice leaves increased significantly after applying bacterial fertilizer.As time went on,the activity of POD increased first and then decreased,while the activity of SOD decreased gradually.3)Atrazine bioremediation bacterial fertilizer can inhibit MDA synthesis in rice leaves.The content of MDA decreased significantly after applying bacterial fertilizer.4)Atrazine bioremediation bacterial fertilizer can restore rice growth and yield formation.The results showed that the plant height,tiller number,fresh weight and dry weight of shoot and root were significantly increased,and rice yield was significantly increased compared with the control.5)Atrazine bioremediation bacterial fertilizer can significantly reduce the content of atrazine in soil.The atrazine content decreased significantly after 7 days of spraying bacterial liquid.The reduction effect of atrazine residue of conventional fertilization + granular bacterial fertilizer as seed fertilizer + powdered bacterial fertilizer seed dressing + water soluble bacterial fertilizer foliar spraying treatment was the most significant.6)Atrazine bioremediation bacterial fertilizer can improve soil enzyme activity in paddy field.The soil urease and phosphatase activities of all treatments were significantly increased after the application of bacterial fertilizer.The soil enzyme activities of the treatment conventional fertilization + granular bacterial fertilizer as seed fertilizer + powdered bacterial fertilizer seed dressing + water soluble bacterial fertilizer foliar spraying were the highest.7)The results showed that the treatment of conventional fertilization + granular bacterial fertilizer as seed fertilizer + powdered bacterial fertilizer seed dressing + water soluble bacterial fertilizer foliar spraying had the best comprehensive restoration effect.The plant height,fresh weight,dry weight and tiller number of rice were the highest,chlorophyll content,antioxidant enzyme activity,soil urease,phosphatase and cellulase activities were the highest,while MDA content and soil atrazine residue were the lowest,The yield of upland rice was the highest and it was the best application method.Spraying bacteria liquid after 28 days,compared with the control,the chlorophyll content was significantly increased by 31.30%,POD activity increased by 63.02%,SOD activity increased by 629.71%,and the MDA content decreased by 57.43%,atrazine residue decreased by 88.89%,while the urease,phosphatase and cellulase activities in root soil increased by 528.62%,49.17% and 35.15%,respectively,and yield increased by 12.74% and 11.56% in two years.(2)Different application methods of clomazone bioremediation bacterial fertilizer had different degrees of remediation effect on coriander,spinach and their rhizosphere soil.1)Clomazone bioremediation bacterial fertilizer could recover and increase the chlorophyll content in leaves of coriander and spinach.After the application of bacterial fertilizer,the results showed that the chlorophyll content of each treatment was significantly higher than that of the control with clomazone in soil.As time went on,the chlorophyll content of coriander leaves increased and then decreased,while that of spinach increased first and then stabilized.2)Clomazone bioremediation bacterial fertilizer can restore and improve the antioxidant enzyme activities of coriander and spinach leaves.The activities of antioxidant enzymes in all treatments were significantly increased after applying bacterial fertilizer.With the passage of time,the activities of SOD in spinach leaves increased gradually,while the activity of POD increased firstly and then decreased;as for coriander leaves,the POD activity decreased gradually,while the SOD activity increased gradually.And the content of MDA in each treatment was significantly lower than that in the clomazone soil control group without bacterial fertilizer treatment3)Clomazone bioremediation bacterial fertilizer can repair and improve the growth quality of coriander and spinach.The fresh weight and dry weight of each treatment increased significantly after applying bacterial fertilizer,and continued to increase with time.The application effect of the treatment of conventional fertilization + granular bacterial fertilizer as seed fertilizer + powdered bacterial fertilizer seed dressing + water soluble bacterial fertilizer foliar spraying was the best,because it had the highest yield,which were 203.45% and 181.03% higher than that of the control with clomazone,and 67.09% and 58.25% higher than that of the control without clomazone.4)Clomazone bioremediation bacterial fertilizer can significantly reduce the residual content of clomazone in the rhizosphere soil of coriander and spinach.After 7 days of spraying bacterial solution,the residue of clomazone in rhizosphere soil decreased significantly.The application effect of the treatment of conventional fertilization + granular bacterial fertilizer as seed fertilizer+ powdered bacterial fertilizer seed dressing + water soluble bacterial fertilizer foliar spraying was the best,having the lowest clomazone residual,which were 83.06% and 76.03% lower than that in the control soil with clomazone and it was the best application method of clomazone bioremediation bacterial fertilizer.