Design and test of control system on variable fertilizer applicator for winter wheat

This variable rate fertilizer applicator based on crop canopy real-time spectral information (normalized differential vegetation index, NDVI) was designed to applicate real-time variable fertilization for the winter wheat.By real-time spectral information of crop canopy via six spectrum sensors, and speed of the tractor via velocity-measuring system, the expert system of the applicator could adjust the rate of the fertilizer according to the feedback fertilizer flow under fuzzy PID(proportion integration differentiation) controller.The experimental results indicated that the fuzzy PID had the good tracking performance and dynamic stability.The system precision could reach above 90%, and the measuring absolute error of the traveling speed was within 0.25 km/h.