भाकृअनुप - केन्द्रीय कृषि अभियांत्रिकी संस्थान, भोपाल

Spectral Sensor Based Handheld Nitrogen Estimation Device for Tomato Crops

Nitrogen is a critical nutrient for tomato crops as it directly impacts plant growth, chlorophyll production, and fruit yield. Given the shallow root system of tomatoes, managing nitrogen effectively is vital to ensure optimal crop health and maximize productivity. Traditional nitrogen estimation methods, which often rely on laboratory equipment, are time-consuming, costly, and not always practical for field use. To overcome these limitations, a handheld device has been developed, leveraging spectral reflectance technology coupled with machine learning models to estimate nitrogen levels in real-time. The core of the device is the spectral sensor, which captures key nitrogen-sensitive wavelengths within the visible to near-infrared range (410–940 nm). These spectral measurements are processed by the microcontroller, which ensures real-time data analysis. The device features an intuitive user interface with a small, compact design for ease of use in the field. A rechargeable Li-ion battery provides up to 6-8 hours of continuous use, ensuring long-term operational efficiency, while an SD card allows for data logging and review of past readings. The device can classify nitrogen levels into five different stress categories with an accuracy of 83%. The cost of the device is approximately ₹15,000, making it an affordable tool for small- to medium-scale farmers seeking to enhance crop management.