P.P. Pawase, S. M. Nalawade and N.R.N.V. Gowripathi Rao
Abstract
The nutrient management depends on selection of nutrient, application rate and placement of nutrient at the optimal distance from the crop and soil depth. Constant rate fertilizer application across entire field can result in over or under incorporation of nutrients. To mitigate this problem a real-time variable rate fertilizer application system was developed for on target nutrient application. The system consisted of microcontroller, Nitrogen sensor, Proportional Solenoid Valve, Pressure relief valve, Pump, Battery, etc. The microcontroller system was designed to receive a signal from the Green-seeker sensor and send a signal to the proportional solenoid valve (PWM capabilities) to vary the discharge according to valve opening based on the recommended dose of nutrients. The field study was conducted on Maize crop. The response time between the Nitrogen Sensing and fertilizer discharging fell within the range of 1.12 to 1.80 s observed at 3 km/h forward speed. The four levels of fertilizer rate and three levels of forward speed were decided from N1 to N4 (150, 200, 250, 300 l/ha) and 3, 4, 5 km/h, respectively. It was observed that as operating speed increases the % error increased. The maximum % error was observed at 5 km/h speed and N1 level of fertilizer which was 8.4. The performance of developed variable rate fertilizer applicator was found better at a speed 3 km/h, because at this speed the minimum % error was observed. Using developed variable rate applicator, the percentage liquid saving was varying from 14.28 to 24.30%.