It is inevitable to encounter various problems in flight prevention operation. Aiming at these problems, Qingyu puts forward its own solutions and special additives for flight prevention.

　　The first is about particle size. There are objective differences between practical application and theory. In the textbook, the theoretical optimal bioactive particle size is 50 μ m ~ 200 μ m, but in actual flight control operation, we must consider evaporation, drift and other factors. In fact, only large droplets can resist drift well, because the droplet size is much larger than our theoretical particle size.

　　The theoretical droplet drift is very serious at 3m / s. The smaller the droplet is, the farther it drifts and the easier it is to evaporate. If the field is large enough, the droplets will always fall on the crops, but in fact, with the increase of drift distance, evaporation will increase during the drift process, and it will be difficult to effectively deposit on the leaves.

　　At the same time, the influence of high concentration dilution should be considered. The first is the problem of pesticide damage, and the second is the mixture of many kinds of drugs. At this time, if the compatibility and stability are not good, it is easy to bring the problem of pesticide damage. On the right side of this picture is when high concentration is diluted, if the gust is encountered, if the spray of the two spray is stacked together, it is easy to cause the burn blade. The second figure on the left is abamectin EC, which is commonly used on rice. A lot of avermectin emulsifiable concentrate on the market is prepared with ointment, its stability is very poor, and it is easy to have problems if it is applied in the flight prevention scene. Therefore, if avermectin emulsifiable concentrate is to be used for flight control, it should be prepared with refined powder or optimized formula.

　　The problem of pesticide damage caused by drift mainly focused on the herbicide flight control operation, including the impact of natural wind and local wind field.

　　As shown in the figure, the typical case is caused by herbicide drift in flight control operation, which is also some experience and lessons accumulated in the operation process. We carried out the flight control operation of herbicide in the upwind direction. There was still a rice field in the middle. However, because of the wind direction at that time, it passed through the village and passed through the middle of two rows of houses. Due to the narrow pipe effect of local wind field, the drift distance was very far. The straight-line distance between the lotus pond and the spraying operation was more than 800m, which still caused the drift to other crops It has an impact. In fact, after the local agricultural technology department came to the scene for identification, it was found that the damaged lotus root pond showed an obvious trumpet shaped radial distribution, and it was affecting the two rows of residential buildings, that is to say, it was caused by the wind.

　　There are few reports on flying control pesticide damage in European and American countries. One of the objective factors is that the land area is large, and it is often a single planting area. Therefore, even if there is drift, the impact of pesticide damage is very small. The land area of Chinese farmers is relatively small, and the diversity of crops planted, it is easy to cause pesticide damage to other crops after drift. In general, when the wind force increases to 2 ~ 3, the downwind direction of the operation area is easy to produce pesticide damage. At present, there are relatively few herbicide flying control operations in East China and North China, and most of them are concentrated in Northeast China, which is also related to large-scale continuous planting in Northeast China.

　　In this application scenario, three main conditions need to be met. The first is the ability to resist drift and evaporation. This is mainly achieved by adjusting the droplet size and controlling the emergence of droplets < 50 μ M. in fact, in front of a large number of application data, droplets below 100 μ m often suffer from drift, which aggravates their evaporation loss. Droplets below 50 μ m cannot be effectively deposited on the surface of crops, which is considered as invalid droplets. The second is to effectively improve the compatibility of bucket and mixer in flight defense package. Third, it is necessary to enhance the quality of spray after adding the additives, especially for the improvement of deposition.

　　The traditional methods of operation, the water consumption of the spraying machine and the artificial spray are relatively large. The droplet density and deposition amount of the objective are far higher than the deposition amount of the fly protection. At this time, the spray quality of flying prevention is especially important for the influencing factors of the efficacy. It is very important to add spray assistants to improve the adhesive force of the liquid on the leaf surface, reduce the rebound and slide, and help the wetting and spreading of the liquid on the target.

　　The flight prevention package containing traditional WP and WDG dosage forms, as well as the same products and packages with different combinations of dosage forms, tend to be much less stable, which may appear unstable in about five minutes.

　　By adding yunfeibao, a special anti-aircraft additive developed by kingyu, as shown in the gray curve in the figure, it can be clearly found that it can effectively improve the compatibility and stability of the package.

　　After adding fertilizer components, it is not always unstable in the early stage. But after a certain period of time, the phenomenon of instability suddenly appears. However, the whole system becomes relatively stable after adding suitable flight control additives。

　　In order to better detect and characterize how to control the generation of small droplets and improve the anti drift ability of the liquid medicine, we have built our own laboratory droplet transfer evaluation system, or wind tunnel. In this system, it can be seen that the droplet size changes with or without additives after the solution of different components and concentrations comes out of the nozzle. Through the system detection, it can be clearly seen that by adding suitable flight control additives, the droplet size distribution of the whole droplet spectrum is more uniform, the effective particle size is mainly around 150 μ m, and the droplet spectrum distribution becomes more uniform.

　　It is obvious to increase the droplet density and deposition on the leaf surface by adding yunfeibao.

　　After the water sensitive paper collects the droplets, it will be analyzed by software. Not only the droplet size, but also the droplet density, coverage and other indicators will be significantly improved.

　　It is necessary to solve the application requirements of the application scenarios. It can improve the serious problem of droplet drift caused by the working environment, including the control of droplet size, the selection of suitable flight control additives, and the formation of moisture retention and anti evaporation of the liquid medicine reaching the target surface under high temperature conditions. At the same time, it is necessary to reduce the damage and increase the adhesive property of the solution on the leaf surface.