Journal of Agronomy and Field Innovations

Background: Fertilizer management has traditionally been based on uniform application of fertilizers across fields despite substantial spatial variation in soil fertility. This causes problems on fertilizer use efficiency, production costs and the environment such as nitrate leaching, nutrient runoff and eutrophication. The advances in precision agriculture technologies create new possibilities to improve the efficiency of nutrient management by applying a site-specific approach to this issue.
Objective: The objective of this study was to develop and evaluate a framework of integrated site-specific nutrient management (SSNM) using IoT technology together with UAV remote sensing and GIS. We produced maps of variable-rate nutrient prescriptions and compared agronomic, economic, and environmental productivity of the method we developed to traditional uniform fertilization in an irrigated corn production system.
Methods: An experiment was carried out in the agricultural field using an integrated precision agriculture approach that comprised the installation of a set of sensors for assessment of soil moisture, nutrients, electrical conductivity, and temperature.
The UAV images were processed and used for calculation of vegetation indices (NDVI, GNDVI, NDRE) for obtaining information about nutrient levels in crops. The data obtained from the sensors were combined with remote sensing data using GIS method of ordinary kriging to form soil fertility management zones and maps for variable rate application of fertilizers. The results of agricultural efficiency, fertilizer efficiency, fertilizer economy, and environmental effect were evaluated by making comparative analysis with traditional uniform fertilizer use.
Results: The combined IoT-UAV-GIS system had good results in disclosing variations in the spatial distribution of nitrogen, phosphorus, and potassium content in the soil within the studied area. NDRE demonstrated the strongest correlation with the nitrogen status of crops among other indicators of vegetative cover. The new method that enabled the management of nutrients taking into account their peculiarities made it possible to increase the efficiency of nitrogen application by 21%, the efficiency of obtaining production with specified quality by 9%, and to decrease the overall fertilizer application rates by 19% compared to traditional methods of fertilizers application. These changes will lead to net income growth and a decrease in nitrogen surplus.
Conclusion: The use of IoT sensors, UAVs (Unmanned Aerial Vehicles) and GIS (Geographic Information System) together supports the idea of having an efficient solution for accurate management of nutrients. The identification of unevenness in the distribution of the fields and variable rates of fertilizers will ensure better fertilizer efficiency and thus increase fertilizer effectiveness, reduce fertilizer consumption, increase effectiveness of crop production and reduce environmental threats. It can be concluded that digital technologies in agriculture can be applied for the needs of sustainable and climate-friendly agriculture.