Fermentation Process Of Ha1 Strain And Herbicidal Activity Of Granules

The problems of pesticide residues and environmental pollution caused by the long-term high-frequency use of chemical pesticides have become increasingly serious.Under such a large environment,microbial agents have emerged.In this paper,the herbicidal activity of Ha1 was studied.Firstly,the fermentation process was optimized,and the best fermentation process was selected.Secondly,using semolina-kaolin as raw material,Ha1 granules were prepared by adding suspension of Ha1,and its shelf life and herbicidal activity were determined;Combining granules with chemical herbicides for compatibility studies of strains with chemical herbicides and chemical herbicide reduction tests.The research results are as follows:?1?The components of the Ha1 medium were screened by single factor test and orthogonal test.The optimal carbon source of the culture medium of Ha1 was sucrose,the nitrogen source was peptone,and the inorganic salt was chlorinated.Calcium,and the addition amount is 10 g/L,20 g/L,0.1 mol/L.The design of the response surface was designed by Design Exper 10 software.The experiment was optimized by Box-Behnken method.The initial pH,rotation speed and culture temperature were used as the response values.The experimental data were fitted to obtain the optimal shake flask of Ha1 Ha1.The fermentation conditions were:pH 7,temperature 20?,and number of revolutions of200 r/min.?2?Ha1 granules were prepared from semolina-kaolin,and the effects of storage temperature and oil additives on the shelf life of granules were determined.The results showed that when the granules were stored for 9 weeks,the number of viable cells per gram of granules stored at 4?was 1.2×10⁹ CFU bigger compared with the storage conditions at 25?;at 4°C,the number of viable bacteria per gram of granules added with soybean oil auxiliaries was 0.9×10⁹ CFU bigger compared with granules without added soybean oil auxiliaries.?3?Different amounts of Ha1 granules were applied to study the herbicidal activity of Ha1 granules on weeds and the safety of main food crops.The results showed that Ha1granules had certain herbicidal activities against monocotyledonous weed crabgrass and valerian,dicotyledonous weeds,and ramie.When the application rate of granules was 110g/m²,the fresh weight inhibition rates of D.sanguinalis and Echinochloa crusgalli?L.?Beauv.were 57.56%and 63.12%,respectively,and IC₅₀ were 76.035 g/m² and 87.076 g/m²,respectively.The inhibition rate of dicotyledonous weeds and ramie was slightly poor.When the application rate of granules was 110 g/m²,the inhibition rate of fresh A.retroflexus and Abutilon theophrasti was 48.76%and 48.46%,respectively.The IC₅₀ is107.369 g/m² and 106.969 g/m²,respectively.In addition,Ha1 granules have no inhibitory effect on the growth of Triticum aestivum,Zea mays and Sorghum bicolor.?4?Using the growth rate of bacteria and the biocompatibility test of chemical herbicides and strains,the chemical herbicides metolachlor,acetochlor,prometryn,atrazine,acetochlor and methanone were studied.The results of bacterial growth rate showed that the chemical herbicides prometryn,metolachlor and atrazine had no effect on the growth of Ha1 strain at the recommended dosage in the field.The biocompatibility test results of chemical herbicides and strains showed that the compatibility of prometryn,atrazine,and metolachlor was better than that of Ha1 strain,and the amount of bacteria in the treatment group was significantly higher than that in the control group.?5?The biological herbicide Ha1 granules are compounded with different chemical herbicides to control D.sanguinalis,Echinochloa crusgalli?L.?Beauv.and Abutilon theophrasti.The inhibition rate of fresh weight of weeds was determined by pot experiment in greenhouse.The results showed that when 30%reduction of atrazine,prometryn and metolachlor were used alone.The fresh weight inhibition rate of D.sanguinalis was 78.27%,67.47%and 66.59%,respectively,the fresh weight inhibition rate of Echinochloa crusgalli?L.?Beauv.was 78.35%,83.64%and 80%,respectively,The fresh weight inhibition rates of Abutilon theophrasti was 74.49%,43.50%and 37.50%;When treated with 110 g/m² Ha1 granules,the fresh weight inhibition rates of D.sanguinalis,Echinochloa crusgalli?L.?Beauv.and Abutilon theophrasti were 59.42%,58.01%and 40.47%,respectively;110 g/m² Ha1 granules and 30%reduction of atrazine,prometryn and metolachlor were combined,the effects of low seedling rate,short stature and high mortality were slightly worse for ramie.The fresh weight inhibition rates of D.sanguinalis were 96.35%,97.61%,and 94.47%,respectively.The fresh weight inhibition rates of Echinochloa crusgalli?L.?Beauv.were 89.81%,85.68%,and 86.50%,respectively.The fresh weight inhibition rate for Abutilon theophrasti was 86.92%,53.03%,79.53%.When 50%reduction of atrazine,prometryn and metolachlor the inhibition rate of D.sanguinalis and Echinochloa crusgalli?L.?Beauv.was not obvious,and the inhibition rate of fresh weight of D.sanguinalis was 43.76%,46.18%and 40.29%,respectively;the fresh weight inhibition rate of Echinochloa crusgalli?L.?Beauv.was 33.85%,36.66%,10.81%;When Ha1 granules were combined with 50%reduction of atrazine,prometryn and metolachlor the fresh weight inhibition rates of D.sanguinalis were 54.50%,56.47%,and54.22%,respectively.The fresh weight inhibition rates of Echinochloa crusgalli?L.?Beauv.were 57.63%,50.55%,and 50.79%,respectively.Therefore,chemical herbicides reduce the conventional dosage of 30%with Serratia marcescens Ha1 granules,increasing the inhibition rate of weeds by chemical herbicides and granules alone.