Quality evaluation method and optimization of operating parameters in crop aerial spraying technology

Contrasting with terrain-machine, aerial craft is more flexible and efficient.So aerial spraying has abstracted high attention in recent years.It has become the popular trend of crop protection.America was the first country using the aircrafts in aerial spraying, and has gotten the most mature technologies in aerial spraying.Japan, Australia, Russia and Korea also had the advanced technologies and made great progresses all over the world.Many aircraft models have been used in aerial spraying, but the rotor Micro UAV(unmanned aerial vehicle) has been used more widely in aerial spraying, due to the advantages of better adaptability, taking off and landing vertically, and fixed-point hovering.The primary evaluation index for quality of aerial spraying are the droplet distribution coverage, uniformity and spraying drift.The main factors which influence the aerial spraying quality are as follows: aircraft model, nozzle model, nozzle hole diameter, spraying pressure, spraying angle, meteorological conditions(temperature, humidity, wind speed, wind direction), operation height, operation speed, reagent combination and reagent concentration.They affect the deposition character of the droplets on the plants' surface, and then have effect on the spaying quality ultimately.Since the droplets distribution characteristics is the main factor to determine the effect of aviation plant protection, research on the droplet distribution under the condition of different factors can provide references for choosing optimum parameters.How to improve the spray quality and spray efficiency of aerial spraying and the utilization of pesticide, reduce environment pollution, and realize the controllability of droplets are some of the main focuses of aerial spraying at present.Lack of scientific and technological guidance is the cause of blind operations in aerial spraying, which is the main reason of low quality and efficiency of aerial spraying, low utilization of pesticide and severe environment pollution.This paper was based on in-depth analysis of the status of aerial spraying of plant protection, and pointed out the main problems existing in China's agricultural aviation of plant protection were followed: 1) The quality of aerial spraying is general low; 2) There are still room for improvement of spraying efficient; 3) The pesticide utilization ratio in aerial spraying is low; 4) Aerial spraying causes environmental pollution.According to the review, the further research on key technologies should be focusing on building forecasting model for droplet distribution and spraying drift of aerial spraying, and establishing decision-making system to realize controllability of droplets.In this system, users enter the default parameters(aircraft model, nozzle model, nozzle hole diameter, spraying pressure, spraying angle, temperature, humidity, wind speed, operation height, operation speed and reagent), and then, the system outputs the forecasting effect(droplet diameter and droplet distribution).In summary, the methods of aviation technical specification of plant protection and the establishment of decision-making system for major crops(rice and cotton) of China were pointed out, in order to provide a theoretical basis and decision guidance for aerial spraying in China.