Photo credit: FREEPIK
Satellite images are particularly suited for crops such as cereals, maize, and other field crops, as their scale aligns with the spatial resolution of Sentinel-2 satellite imagery. These images, combined with drone technology, provide essential data for implementing Variable Rate Application (VRA) of fertilizers, a core practice in precision farming. Optical satellites and drones equipped with multispectral sensors capture high-resolution imagery and vegetation indices, such as NDVI (Normalized Difference Vegetation Index) and NDRE (Normalized Difference Red Edge Index). These indices help identify field zones that exhibit variability in crop health, growth, or nutrient requirements. Such zones often require further targeted monitoring or additional measurements, such as nitrate levels or soil sampling.
To make fieldwork easier and more efficient, farmers use a dedicated mobile app developed as part of the EIP Precision Farming and Digitalisation project. This app provides field maps that guide users to specific zones for collecting measurements or observations. For example, a farmer can navigate the app to underperforming zones identified by the satellite imagery, enter real-time soil nitrate test results, and input other observations directly into the system. The ability to combine remote sensing data with ground-truthed measurements ensures that the analysis is as accurate and reliable as possible.
Agronomists then analyze the combined data to generate targeted fertilization recommendations based on the actual nutrient needs of the crops. These recommendations are used to create a digital fertilization plan. Farmers transfer these files to their equipment using USB drives, cloud-based systems, or wireless connections, ensuring seamless integration of data.
The integration of satellite imagery, drone-based data collection, soil measurements, and precision machinery enhances the accuracy of fertilizer application. The ability to combine this information with potential soil analysis results allows for a comprehensive understanding of both plant and soil needs. For example, satellite imagery highlights crop health variability, while soil analysis confirms nutrient deficiencies, enabling farmers to tailor fertilizer applications even more precisely.
By using VRA technology, farmers achieve multiple benefits, including improved crop yields, reduced fertilizer costs, and minimized environmental impact. Precision application prevents over-fertilization in healthy zones and provides additional nutrients to underperforming areas, resulting in uniform crop growth and better resource use. This practice not only enhances productivity but also supports sustainable farming practices by reducing nutrient leaching, protecting water quality, and minimizing greenhouse gas emissions.