Sensor Technologies for Precision Soil Nutrient Management and Monitoring

Problem statement: Growing concerns about the need to increase crop productivity without causing environmental injury have led to the deployment of site-specific strategies in soil nutrient management, where nutrients are applied in variable rates to fit local requirements. Variable rate application of nutrients is typically based on a rigorous sampling regime and time-consuming data analyses. The ability to monitor soil nutrient concentration efficiently is highly desirable. Approach: On-site monitoring of soil nutrient concentration offers the opportunity for higher density measurements at relatively lower costs. This would allow for an efficient mapping of nutrient variability to facilitate variable-rate nutrient application. Results: Implementation of nutrient management programs using sensor technology potentially promotes environmental stewardship while maintaining crop productivity and profitability. Rapid and non-destructive quantification of spatially-variable soil nutrients has been made possible with on-the-go sensors such as optical, electromagnetic and electrochemical sensors. Conclusion: This review demonstrates the potential of on-the-go sensors for non-destructive and rapid characterization of soil nutrient variability within crop fields.