An Optical Soil Sensor for NPK Nutrient Detection in Smart Cities

An optical absorbance-based sensor designed to measure the concentration of vital Nitrogen (N), Phosphorus (P) and Potassium (K) nutrients in urban soil was developed. This device was characterized and tested in nine diverse green spaces around New York City's Morning side Heights neighborhood,including street-tree pits and park spaces. The results show that the sensor can detect at minimum, a 1.4% change in nutrient concentration. Additionally, it was shown that the sensor can operate in various ambient light settings (indoor and outdoor) after calibration. A study of NYC's green spaces shows that, on average, soil in street-tree pits that supports plant life has 54% more N, 34% more P, and 37% more K than park spaces, respectively. This new sensor technology will enable more detailed monitoring of soil nutrient conditions and thus help promote healthy green spaces in large urban environments.

Automated summary

An optical absorbance-based sensor has been developed to measure the concentration of essential nutrients in urban soil. The sensor is capable of operating in different ambient light settings and has shown that street-tree pits contain higher levels of nutrients compared to park spaces. This new technology will contribute to better monitoring of soil nutrient conditions and the promotion of healthy green spaces in urban environments.