Model for Smart-Agri app for farmers to enable optimum fertilizer application

For the safe management of these fertilizers (i.e., safe application rates to land), a tool was needed to guide growers and processing plants. A parsimonious program was developed in MS Excel^TM to determine the maximum legal application rate of the different types of DPS and DPS-derived STRUBIAS products based on the soil test P content, the legal limits for N, P and metal application, the dry solid content, and nutrient (N and P) and metal concentration of the DPS and DPS-derived STRUBIAS products.