Nitrate-sensitive areas in Switzerland face the dual challenge of maintaining agricultural productivity while protecting water resources. This study was carried out in the framework of a regional nitrate project in central Switzerland which involves farmers and local stakeholders. The focus is set on the use of satellite-based remote sensing to monitor and assess crop growth and N balances in winter wheat fields in Switzerland over a 3-year period. The primary aim of the study is to link satellite data with field-level soil and crop measurements to evaluate the impact of different standard and site-adapted fertilization methods on N balances. Satellite imagery was collected to capture spatial variability in crop growth across selected winter wheat fields over the course of the study. Soil mineral N (SMN) data, along with crop yield measurements, were collected at regular intervals to calculate field-specific N balances. These N balances, reflecting the difference between N inputs (fertilization) and outputs (crop uptake, leaching), were then correlated with the satellite-derived vegetation indices to assess how different fertilization practices influence nitrogen use efficiency. Preliminary results demonstrate a clear gradient in crop growth across the monitored fields, which is consistent with variations in N application rates and SMN. N rates were reduced up to 20% with site-adapted fertilization recommendation. By integrating satellite monitoring with field data, this study provides valuable insights into the relationship between fertilization practices, crop growth, and N cycling in nitrate-sensitive areas. The findings encourage the use of remote sensing to facilitate precision N management and monitoring in regions with high crop production and need for environmental protection.
