Croptune from Israel’s Agriot can determine the nitrogen content in a plant from an image and judge how much nitrogen-rich fertilizer it needs. The farmer downloads the Croptune Apple / Android app; enters the crop type & location; takes photos and reads the analysis. Saves costs and the environment.
https://nocamels.com/2024/06/green-gauge-app-analyzes-leaf-color-to-understand-crops-needs/
https://www.agriot.group/en/home