Multi-flows Granular Fertilizing Process Optimization In Nutrient Proportion Of Variable Rate Fertilization

The nutrient proportion of variable rate fertilization is one of the key technologies in precision agriculture. Rational nutrient proportion application of chemical fertilizer has very positive meaning to crops development. Nowadays variable fertilization can only adjust one kind compound fertilizer or unit fertilizer consumption online, which cannot adjust N-P-K ratio real-time and difficult to meet the difference demand of soil and crop. This project study on the filed of nutrient proportion of variable rate fertilization, which want to reveal mixing mechanismin of different scale particles in theory, complete accurate control of main nutrients ratio nline, improve fertilizer using efficiency, reduce fertilizer rate, promote development of precision variable fertilization.In this paper, a new nutrient proportion of variable rate fertilization device is proposed, which consists of three fertilizer boxes, three fertilizer apparatuses, three fertilizer dropping pipes, a blending cavity and a corrugated tube. Meanwhile, A 3D discrete element method (DEM) model was constructed using discrete element method (DEM) and three main types of granular fertilizers (Nitrogen, Potassium and Phosphateis) were utilized to research the blending process of fertilizers. Then the device with different shape of blending cavity, different height of fertilizer dropping pipe and different diameter of corrugated tube is simulated, respectively. By tracking the trajectories and recording velocities of fertilizer particles in the fertilizing process, the performance of multi-flows granular fertilizers blending process was evaluated by calculating the mixing standard deviation of three kinds of fertilizer sown on the soil, as the evaluation standard on mixing uniformity of fertilizers, to probe into the mixing and dropping law and the factors influencing particle blending process.In order to verify the simulation results, though the subject we completed the design of a novel nutrient proportion of variable rate fertilization device test-bed, which includs frame design, fertilizer conveying belt design, application of data processing equipment and control system design. Through using high speed camera to record particle motion in real time, analyze the influence of outside groove wheel speed, different mixing cavity and dropping pipe height and different corrugated tube for fertilizes distributing process by image analysis software. At the same time, combined with simulation and experiment, explore the time-delay characteristics of this fertilizer distributing system and give the relation curve between wheel speed and fertilizer consumption, to provide basis data for correting work process error and adjusting the ratio of three kinds of fertilizer.DEM and bench test results comparison demonstrated that the best effect can be achieved when the device has straight wall blending cavity,850mm high fertilizer dropping pipe and 2mm high bellows of corrugated tube. The results revealed that discrete element method could achieve the rapid optimization of multi-flows granular blending process and its fertilization structure.