| Pesticide application is a important mean for pest controlling,as the important link,in agricultural production.However,it is not clear about the influence of various factors on the quality of pesticide spraying,and pesticide application process has less standard.As for spray-rod sprayer,it is very easy to cause the drift and the waste of the fog drift when the speed of the sprayer,spray pressure and the height of the spray rod are not appropriate,it not only reduces the effective utilization of pesticides,but also threatens the ecological environment and human safety.Especially in the wind of the natural environment in the pesticide spraying operations,the process of the negative effects of pesticides is more significant.Therefor,the relationship model between outdoor spraying quality and influencing factors was constructed by the method of experiment,These factors include:environmental factors such as wind speed and wind direction;controllable factors such as spray machine speed,spray pressure,spray rod height and different types of nozzles.Most of the above factors were screened from the existing literature,which may have a significant impact on the spray quality.First of all,in order to reduce the disturbance caused by the uncertainty of the test results,this study was carried out in the laboratory,and the test bench was designed by ourselves.In the test bench,the wind speed and wind direction are simulated by the fan,and the wind speed is calibrated by the wind speed sensor;the spray pressure,the height of the spray nozzle and the nozzle of different types are manually adjusted before the experiment,while the spray machine speed is simulated by different stepping motor drive speed.In order to reduce the subjectivity and human error,the experimental process is controlled by the controller.In the course of the experiment,water sensitive paper was uniformly arranged on the surface of the plant,and the results were photographed and storaged after drying.In order to avoid the interference of random factors,each test was repeated at least 3 times to ensure the validity of the test data.Secondly,the experiment was carried out by the combination of single factor test andcombinational factor test.This study was divided into three parts: 1.Single factor experiment under the condition of no wind.Without considering the influence of wind speed and wind direction,the test fan was closed and the standard test conditions were designed,that is,the speed of sprayer was 3.6m/s,spray pressure was 0.4MPa,and theSpray nozzle used Hypro-03 type.Only a factor was changed in each test,thus the effect of each factor on spray quality was researched.The changing range of each factor was: the speed of sprayer was 3.0,3.3,3.6,3.9,4.2m/s,spray pressure was 0.2,0.3,0.4,0.5,0.6MPa,the nozzle height was 0.5,0.6,0.7,0.8,0.9m,and the spray nozzle used Hypro-01,Hypro-02,Hypro-03,Hypro-04,Hypro-05 type,respectively.2.Combinational factor test under the condition of no wind.Four factor and three level orthogonal test method was carried out,and the factors considered are the same as those of the single factor experiments under the condition of no wind.Test levels were taken as the speed of sprayer was 3.0,3.6,4.2m/s,the spray pressure was 0.2,0.4,0.6MPa,and the nozzle height was 0.5,0.7,0.9m,the spray nozzle used Hypro-01,Hypro-03,Hypro-05 type,respectively.3.Combinational factor test under wind conditions.For each set of different wind speeds(0.9,2.5,4.4m/s)and wind direction(0,45,90,135,180o),the four factor and three level orthogonal test was carried out repeatly for the optimization of the best influencing factors in different wind speed and wind direction.Finally,the water sensitive paper images were scanned and processed by DepositScan,and the final test datas were obtained.The single factor test results showed that the spray quality increases slowly with speed promoting when the range of speed below 3.6 km/h,however,the spray quality significantly decreased with speed promoting.The influence of spray pressure,spray rod height and nozzle type on spray quality were the same as that of velocity,its best choice was which the pressure was 0.4MPa,the height was 0.7m,and the nozzle used Hypro-02(or Hypro-03),successively.The results of combinational factor test under the condition of no wind showed that the optimum parameters of spray was the speed of sprayer as 3.0 km/h,the spray pressure as0.4MPa,the nozzle height as 0.7m,and the nozzle type as Hypro-01,successively.The combinational factor test under wind condition showed that if the wind speed and wind direction were combined into 24 specific annular regions,and the parameters of eachloop were optimized respectively.The speed has the most selected number is 3.6km/h as 12times;the pressure has the most selected number is 0.4MPa as 13 times;the pressure has the most selected number is 0.5m and 0.7m as 10 times completely;the nozzle type has the most selected number is Hypro-01 as 10 times.Obviously,the he best choice of the most parameters were consistent with the standard conditions in addition to the nozzle type under windy condition.Based on the previous researches,the most favorable combination of parameters is the speed as 3.6km/h,the pressure as 0.4MPa,the nozzle height as 0.7m,and the nozzle type as Hypro-01 when the sprayer is working outdoors(whether there is a natural wind). |
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