Abstract:  The variable application technology aims to improve the utilization rate of pesticides, reduce agricultural costs, appropriately reduce the amount of pesticides, reduce pesticide residues, and reduce environmental pollution. It is an important topic in precision agriculture and the development direction of pesticide application technology. This paper summarizes the field information collection method, the variable application control method, and the variable application control algorithm in the key technology of variable application. Firstly, the field information acquisition technology based on geographic information technology and realtime sensor technology is explained. The second analysis includes variable pressure regulation, chemical concentration regulation, and pulse width modulation variable application control methods and analyzes the advantages and disadvantages of each control method. Pulse width modulation has broad application prospects because of its better dynamic response characteristics and flow regulation performance. Finally, the most important variable application control algorithms (fuzzy control algorithm, PID control algorithm, and BP neural network) are summarized and researched. It is understood that the combination and improvement of different algorithms improve the variable application control performance. Aiming at the problems of domestic variable application technology, suggestions are made to provide a certain reference for the development and promotion of variable application technology in my country.

Key words: variable pesticide application, field information collection, variable pressure adjustment, liquid concentration adjustment, pulse width modulation, control algorithm

摘要： 变量施药技术以提高农药利用率，降低农业成本，适当减少农药用量，降低农药残留，减轻环境污染为目的，是精准农业领域的重要课题和施药技术的发展方向。从变量施药关键技术中的田间信息采集方式、变量施药控制方式和变量施药控制算法三个方面进行综述，首先阐述基于地理信息技术和基于实时传感器技术的田间信息采集技术；其次分析包括变压力调节式、药液浓度调节式和脉宽调制式的变量施药控制方式，并剖析各控制方式的优缺点，脉宽调制式因其具有更好的动态响应特性和流量调节性能，拥有广阔的应用前景；最后对当前最主要的变量施药控制算法（模糊控制算法、PID控制算法以及BP神经网络）进行概述与研究，了解到对不同算法进行组合和改进有利于提高变量施药控制性能。针对国内变量施药技术存在的问题，提出建议，旨在为我国变量施药技术的发展与推广提供一定的参考。

关键词: 变量施药, 田间信息采集, 变压力调节, 药液浓度调节, 脉宽调制, 控制算法