[An optical-fiber-sensor-based spectrophotometer for soil non-metallic nutrient determination]

Area of Science:

• Agricultural Science
• Analytical Chemistry
• Spectroscopy

Context:

• Soil testing is crucial for effective fertilizer recommendations.
• Existing methods for soil nutrient determination can be time-consuming and lack portability.
• There is a need for rapid, convenient, and efficient soil analysis tools.

Purpose:

• To develop a portable optical-fiber-sensor-based spectrophotometer for non-metallic soil nutrient determination.
• To evaluate the performance of the developed spectrophotometer against national standards.
• To compare the accuracy of the prototype instrument with commercial spectrophotometers.

Summary:

• A portable spectrophotometer utilizing an immersed fiber sensor, holographic grating, and diode array detector was engineered.
• The instrument demonstrated compliance with national standards (JJG 178-2007) for wavelength accuracy, stability, and light transmission.
• Significant linear correlations were observed between the prototype's measurements and those from commercial spectrophotometers for various soil nutrients, including nitrate nitrogen, ammonia nitrogen, phosphorus, sulfur, boron, and organic matter.

Impact:

• The developed spectrophotometer offers a viable solution for rapid and accurate soil nutrient determination.
• This technology can enhance the efficiency of soil testing and fertilizer recommendation processes.
• It provides a high-accuracy, field-deployable alternative for agricultural soil analysis.