Effect Of Acetochlor And Metolachlor Application Between Plastic Mulches In The Filed On Security Of Foxtail Millet

Millet is an important grain reserve crop with abundant nutrition,drought tolerance and barrenness tolerance.It has become an important grain reserve crop to cope with the increasing shortage of water resources in the future and plays an important role in the adjustment of agricultural structure in dryland areas of China.With the rapid development of the herbicide industry and the rising cost of agricultural production management,chemical weeding has become one of the main ways of soil management in field crops.The problem of resistant weeds in tanida is becoming more and more prominent because of the fewer kinds of herbicides and the long-term and excessive use of the same herbicides.Long-term and excessive use of the same herbicides,the problem of cereal-resistant weeds is becoming more and more prominent.Film-mulching is one of the important sowing methods for dryland millet.It can not only increase the temperature and protect the grain,prolong the growth period of millet,but also control the weeds under the membrane well.There are many kinds of weeds in the membrane and the damage is heavy,which not only affects the yield of millet.And quality,but also bring difficulties to mechanized cultivating and harvesting,and become the bottleneck of industrialization,scale and modern production of millet.In response to this problem,this study selected acetochlor and metolachlor in the amide herbicide to spray herbicides in the aisle between the mulch and the mulch,from seedling growth,physiological and biochemical indexes,photosynthetic fluorescence characteristics and In terms of yield,this technology explores the safety of this technology for millet,in order to select new herbicide varieties and application techniques for millet chemical weeding.The Zhangza Gu 10 and Jingu 21 was taken as the research object,Four doses were set: 2.25 L/hm~2(A1),4.50 L/hm~2(A2),6.75 L/hm~2(A3),9.00 L/hm~2(A4)of acetochlor and 3.00 L/hm~2(B1),6.00 L/hm~2(B2),9.00L/hm~2(B3),12.00 L/hm~2(B4)of metolachlor,tap water served as control treatment,no weeding was CK.Spraying equal amount of clear water.The effects of herbicides on Photosynthetic fluorescence characteristics,soluble protein content,protective enzyme system,MDA content,root activity and yield Characters of Millet leaves were studied.The control effects of two closed herbicides on weeds in tanida were also studied.The main results are as follows:1.With the increase of herbicide dosage,the SPAD value,net photosynthetic rate(Pn),stomatal conductance(Gs),maximum photochemical quantum yield of PSII(Fv/Fm),potential activity of PSII(Fv/F0),actual quantum yield of PSII(Y(II)),photosynthetic electron transfer rate(ETR(II))and photochemical quenching coefficient(q P)of leaves of Zhangzagu 10 and Jingu 21 decreased gradually.The,stomatal limitation value(Ls)and non-optical quenching coefficient NPQ increased,while the soluble protein increased first and then decreased.2.25-4.50 L/hm~2 acetochlor,3.00-9.00 L/hm~2 isopropylalachlor inhibited photosynthesis of Zhangzagu 10 and Jingu 21.The photosynthetic activity of millet leaves was relatively mild.Millet could maintain a certain degree of photosynthesis by adjusting SPAD value,soluble protein content and enhancing heat dissipation.6.75-9.00 L/hm~2 acetochlor,12.00 L/hm~2 isopropylalachlor could inhibit photosynthesis of millet leaves.The photosynthetic activity of Foxtail Millet leaves caused irreversible damage and seriously restricted photosynthesis.Acetochlor and metolachlor hindered the synthesis of photosynthetic pigments and soluble proteins,inhibited the activity of photosystem reaction centers,and resulted in the decrease of Pn.It indicated that the decrease of photosynthesis after herbicide spraying was mainly caused by non-stomatal factors.In conclusion,Jingu 21 was more sensitive to acetochlor and metolachlor than Zhangzagu 10,and acetochlor had higher inhibition on Millet than metolachlor.2.The application of acetochlor and metolachlor caused the changes of SOD,POD,CAT activity,MDA content and root activity in Millet leaves.The two herbicide treatments,Zhangzagu 10 and Jingu 21 SOD,POD activity increased first and then decreased.In the early application period,the CAT activity of the two varieties treated with acetochlor showed an upward trend.Fifty days after treatment,it showed a trend of first increasing and then decreasing.The two varieties treated with metolachlor showed an upward trend with the increase of dosage,indicating that CAT played a role after SOD and POD.The protective enzymes activities of 6.75-9.00 L/hm~2 acetochlor and 12.00 L/hm~2 isopropylalachlor treatments were significantly different from those of non-herbicide control.MDA content increased with the increase of dosage,indicating that millet was under herbicide s tress,which resulted in the accumulation of reactive oxygen species and the occurrence of membrane lipid peroxidation in seedlings,destroyed the whole cell membrane,and accompanied by the decline of root activity.With the extension of application time,the activities of SOD,POD and CAT increased gradually,which indicated that herbicide stress was alleviated.Millet alleviated the adverse effects of herbicides by regulating its physiological metabolism through the coordination between protective enzyme systems and root activity.Metolachlor was less harmful than acetochlor.3.The results of morphological index of millet and weed control effect showed that: The low-dose(2.50-4.50 L/hm~2 acetochlor,3.00-9.00 L/hm~2 metolachlor)treatment showed no significant difference in seedling emergence rate compared with the control.The leaf area at the late application period was significantly higher than that of the control.High dose(6.75-9.00 L/hm~2 acetochlor,9.00-1.00 L/hm~2 metolachlor)significantly inhibited the emergence rate,plant height and leaf area of millet.With the application of time,the weeds were harmful,and the height of the control plants without weeding was significantly higher than that of each treatment;The high-dose control of grass weeds is better,up to 99%,and the control effect on broad-leaved weeds is up to 90%;The yield of two millet varieties increased at first and then decreased with the increase of the dosage of acetochlor and metolachl or.Compared with the control,the yield of 2.25-4.50 L/hm~2 acetochlor increased by 37.88%,19.51% and 25.53%,12.92%,3.00-9.00 L/hm~2 metolachlor to Zhangzagu 10 and Jingu 21 by 24.26%,33.51%,respectively 22.40% and 22.20%,15.26% and 7.66%.4.There are few reports about the application of acetochlor and metolachlor in rice field.In this study,the application of acetochlor and metolachlor in rice field was tested directly when screening herbicide varieties.It was found that all treatments of millet suffered obvious pesticide damage,but the pesticide damage could be significantly alleviated by directional spraying technology between films.To sum up,the recommended dosage of film mulched hill-sowing millet was 2.25-4.50 L/hm~2 50% acetochlor and 3.00-9.00 L/hm~2 72% isopropylalachlor.