Comprehensive study of on-the-go sensing and variable rate application of liquid nitrogenous fertilizer

Abstract

Variable rate technology (VRT) provides a sustainable, efficient, and cost-effective nutrient application option. A pioneered study is carried out to develop a variable rate liquid fertilizer application system to detect on-the-go deficiency of Nitrogen within a field and apply it according to the requirement of crop. The system includes microcontroller, nitrogen sensor (i.e. Green-seeker sensor), proportional solenoid valve, pressure relief valve, pump, battery, etc. Microcontroller receives a signal from Green-seeker sensor and it transmits to the proportional solenoid valve (PSV). The PSV opening is change based on the prescribed nutritional dose. The experimental study is conducted on groundnut crop. The experiment is carried out for different level of fertilizer (N1-150, N2– 200, N3-250, and N4-300 l ha−1) as well as different operating speed is 3, 4, 5 km h−1 to estimate actual fertilizer dropped (AFD), % error, droplet size, droplet density (DD), uniformity coefficient (UC), and spray deposition. The response time of the system is in the range of 1.12 s to 1.80 s. It is observed from the experimental study that the error in the fertilizer to be dropped and AFD increases with increase in the speed of operation. The percentage error is found to be 2.73 %, which is the lowest one, at 3 km h−1 operating speed. The maximum droplet size is found to be 272.5 μm at 5 km h−1 forward speed and 300 l ha−1 nitrogen application rate, whereas minimum droplet size is found to be 241.23 μm at 3 km h−1 forward speed and 150 l ha−1 nitrogen application rate. The present study proposes maximum of 24.30 % saving in the fertilizer application for groundnut crop. Thus, the present system improved fertilizer use efficiency, profitability while minimizing environmental hazards.