Design And Experiment On Air-blast Rice Side Deep Precision Fertilization Device

Rice is the most important crop in China. Fertilization is an important process of rice production, which directly affects the yield of crops, rational and efficient use of fertilizers can increase crop yields. At present, the mechanization level of rice fertilization is very low in China, and the artificial fertilization with a large amount of fertilizer causes the uneven distribution of fertilizer. The side deep fertilization for rice is an ideal way of fertilization. The fertilization device will apply fertilizer(basal and tiller fertilizer) quantitatively and with one-time positioning based on the agronomic requirements, and it can carry out a uniform fertilization to the rice’s side position with a certain depth, which can reduce nitrogen fertilizer amount of 20%-30% compared with the traditional fertilization operation. It is a cultivation technique with high output, stable yield and low cost. In view of the low-level mechanization of rice fertilization in China, the large amount of fertilizer application and the low fertilizer utilization in the traditional manual fertilization, combined with the agronomic characteristics of side deep fertilization, we analyzed the fertilization method of wind delivering and developed the air-blast rice side deep precision fertilization device.(1)This device adopted the modularization design and was combined with riding type rice transplanter for use. In the process of operation, the fertilizer granules fell into the deep trench with a certain amount under the effect of gravity and wind; the trench with 5 cm depth was dug by fertilizer exports at the position 3 cm away from seedling side, and the fertilizers would be covered in the mud by covering plate. The device used the rated voltage of 12 V and the power of 72 W; the blower was used to transport fertilizer based on the Venturi effect, and the inner diameter of fertilizer conveying pipe was 25 mm and the velocity was 21 m/s; the global position system(GPS) was used to measure transplanter speed.(2) Precision fertilization control method using the vehicle speed and the speed of the drive motor of fertilizer real-time match, which could match the vehicle speed and drive motor speed in real time. Fertilization controller uses STC12C5A60S2 as a microcontroller, using RS232 control terminal to communicate with the vehicle, the vehicle-mounted terminal receives control commands and query and report job status controller data collected, the motor speed. Motor drive used the AQMD2410 NS direct current motor drive, and drive motor speed using PID controller integrated way to achieve steady speed.(3)The use of C ++ integrated development environment designed for in-vehicle terminal control software control interface fertilization, the interface could display the current operating data, and meanwhile, the user could set the working parameters according to the actual operating requirements. When presetting fertilization amount to 300 kg/hm2, the motor rotation speed was 10r/min, 20r/min, 30r/min and 40r/min, respectively. The fertilizer difference test with 6 fertilizer discharging ports was carried out, and the coefficients of variation of fertilizer application amount were 2.3%, 2.1%, 2.2% and 1.8%, respectively.(4)The experiments were conducted on Heilongjiang Seven-star Farm, and the result showed, planting and fertilization could be done completely and independently in one time when fertilization device and riding type rice transplanter operated. When the preset rate of fertilization was 300kg/hm2 and the vehicle speed was 1m/s, the fertilization device could realize the precision fertilization, and the deviation of fertilization application amount was within 5.82%, fertilization error can be controlled at a lower level.The research provides reference for the development of the rice variable fertilization control technology and the research and development of the rice side deep fertilization device.