Abstract: In order to solve the problems of difficult labor, expensive labor, high labor intensity, low operation efficiency, and insufficient integration of agricultural machinery and agronomy in facility vegetable production, a control system of unmanned ditching fertilizer applicator for facility vegetable production based on PLC and adaptive Fuzzy-PID was designed. Siemens S7-200 SMART PLC was used as the main controller to develop the control system of the ditching and fertilizing machine to realize unmanned ditching and fertilizing; and then the adaptive Fuzzy-PID control method was used to realize precise fertilization. Through the experiment, the maximum relative error of trenching depth was 7.5%, the average relative error was 1.2%, the maximum relative error of fertilization amount was 14%, and the average relative error was 6.6%, which met the requirements of trenching control and precise fertilization. The control system had good stability and high control accuracy, and also met the production requirements.