Advances in the Use of Remote Sensing Techniques to Assess Crop Nitrogen Status

Nitrogen (N) plays a crucial role as a vital nutrient for producing food, fiber, and biofuels. Nevertheless, the utilization efficiency of N is relatively low throughout the entire cycle, from crop fertilization to human consumption and waste. Nitrogen constitutes approximately 78% of the Earth’s atmosphere and is essential for sustaining all life forms. Approximately 120 million tons of synthetic N are utilized annually in agriculture worldwide. This article delved into the global challenges N poses in agriculture and its environmental consequences. It comprehensively examined diverse methodologies for evaluating crop N levels, from traditional to advanced techniques. It further highlighted the immense potential of remote sensing as a critical tool for monitoring, assessing, and forecasting crop N status. Key areas explored include the worldwide N challenges, agricultural N issues and environmental concerns, strategies for appraising crop N content, conventional and innovative approaches for crop N evaluation, the pivotal role of remote sensing in predicting crop N levels, the prospects of remote sensing in canopy N assessment, collection and analysis of crop samples for N determination, N status indicators and their correlation with crop yield, integration of remote sensing with other N assessment techniques, and the translation of canopy N content to grain protein levels. Additionally, this article addressed the challenges associated with remote sensing for crop N assessment and presents a forward-looking perspective. The significance of remote sensing in enhancing N management practices, optimizing agricultural productivity, and mitigating the environmental impact of N pollution has been emphasized.