Optimizing Winter Wheat Nitrogen Management: A Remote Sensing Approach for Tiller Density Estimation and Precision Fertilization

Addressing the global demand for increased cereal productivity and quality, particularly in winter wheat cultivation, necessitates careful nitrogen (N) fertilization management. In high-input systems, improper N fertilizer use contributes to environmental pollution. To enhance N use efficiency, continuous monitoring of N status during crop growth is essential. Manual data collection for biomass and N status is labor-intensive and costly, urging the exploration of rapid and nondestructive techniques. Remote sensing, particularly with sensors on Unmanned Aerial Vehicles (UAVs), offers real-time monitoring with advantages of spatial and temporal flexibility. Tiller density in winter wheat significantly impacts yield, emphasizing the need for accurate and real-time assessment methods. Current tiller density measurement methods are laborious and prone to errors. Remote sensing, offering quantitative biophysical parameters, presents a promising alternative, yet challenges remain in achieving the required accuracy. This study explores the use of aerial indices, specifically NDVI and NDRE, for estimating tiller density in winter wheat. The research integrates field experiments, georeferencing, aerial mapping, UAV data collection, and advanced statistical analyses, conducted in Gujranwala, Pakistan. Results show a strong correlation between aerial NDVI/NDRE and tiller density, providing an alternative to direct measurements. The study proposes nitrogen rate recommendations based on NDVI and NDRE, offering a nuanced approach for effective nitrogen application. The methodology, results, and recommendations contribute valuable insights for optimizing wheat cultivation practices, particularly in nitrogen management, on a larger spatial scale.