| Xinjiang is the second largest walnut growing province in China,and the walnuts in Xinjiang are mainly concentrated in the southern Xinjiang region.Aksu,Kashgar and Hotan alone account for 96.96%and 99.53% of the total walnut area and output in Xinjiang.The insect pest of walnut is very much,according to the statistics have more than 180 kinds of insect pests,more than 30 kinds of diseases.Applying pesticides(without airflow assistance)directly to these walnut trees with a high pressure spray gun will deposit most of the pesticide solution on the outside of the crown,reducing the uniformity of coverage,especially in the middle of the crown.Therefore,transporting the sprays to the tree canopy and assisting them to penetrate into the canopy and distribute them evenly throughout the tree will effectively improve pest control of walnuts.However,compared with some foreign and domestic cultivation modes,the unique intercropping mode of walnut in southern Xinjiang accounts for more than 90% of the total cultivation area,which is characterized by strong tree potential,large crown,disordered tree shape and wide row spacing.Walnut as a kind of perennial tree,its planting pattern is difficult to change at the later stage.Therefore,a spraying machine that conforms to its model is needed.However,there is no spraying machine for the unique pattern of walnut garden in southern Xinjiang at home and abroad.Based on the planting mode and agronomic characteristics of walnut garden in southern Xinjiang,this study designed and manufactured an air-driven spray machine with infrared variable spray technology by referring to high-quality orchard operating machinery at home and abroad.This paper mainly involves the following contents:(1)In the process of research and development,computer aided software was used to determine the selection of key parts of the overall structure of the walnut airfeed spray machine in southern Xinjiang based on the principle of combining agricultural machinery and agronomy,and the manufacturing of the prototype was completed.(2)The walnut wind sprayer in southern Xinjiang combines the profiling device with the flexiblefolding air outlet pipe,and can reasonably arrange the height of the duct and the angle of the nozzle for the actual situation of the walnut at different growth stages,plant height and plant width.Greatly improved the applicability of the machine and the deposition of the liquid medicine.(3)In view of the traditional way of quantitative spraying,it is a great waste of liquid medicine.Based on the overall economic level of southern Xinjiang and the actual needs of walnut growers,an orchard variable spray system based on infrared radiation has been added.In field experiments,the infrared variable spray system was reduced by 62.58 L/ hectare than the actual dosage without opening.Compared with the traditional hand-held high-pressure spray gun,the southern Xinjiang air spraying sprayer without opening the infrared variable spraying system can save 48% of the medicine,while the opening will save55%.(4)Based on fluid mechanics,using the modeling software and fluid dynamics simulation software,the external flow field of walnut wind in southern Xinjiang was analyzed,and the velocity distribution cloud distribution of the external wind field under different nozzle angles of the wind driven sprayer was obtained.According to the cloud map results,the guidance plan for walnut trees with different tree age and canopy characteristics could be applied.(5)In this study,the fog droplet coverage rate of each canopy was taken as the index.The single factor tests of operation speed and nozzle angle were carried out.It was found that the droplet coverage rate of each canopy decreased with the increase of operation speed,no matter at high or low speed of the fan.The effect of nozzle angle on the canopy is mainly reflected in the droplet coverage of the upper canopy.With the increase of nozzle angle,it is conducive to the deposition of droplets in the upper layer of walnut.Finally,the orthogonal experiments were carried out on the three factors with larger spray effect.Through the analysis of MINITAB19 software,taking into consideration three indicators of the upper fog droplet coverage,the middle droplet coverage rate and the lower layer fog coverage rate,it was found that the nozzle angle,speed and diameter of the nozzle bore the greatest impact on each index,and the best combination was A2B3C1.In this condition,the upper droplet coverage rate is 74.192%,the middle droplet coverage rate is 87.184%,and the lower droplet coverage was 76.054%. |
