Suits reflectance models for wheat and cotton: theoretical and experimental tests

Area of Science:

• Agricultural science
• Optics
• Remote sensing

Background:

• Plant canopy reflectance models are crucial for remote sensing applications.
• Suits' models provide a theoretical framework for understanding light interaction with vegetation.
• Validating these models with diverse crop types is essential for their practical use.

Purpose of the Study:

• To test the applicability of Suits' plant canopy reflectance models for cotton and Penjamo winter wheat.
• To investigate the concept of model depth and its implications for reflectance predictions.
• To compare model predictions with experimental field data for different illumination and observation angles.

Main Methods:

• Application of Suits' reflectance models to cotton and wheat canopy data.
• Analysis of specular irradiance exchange symmetry against sun and observer angles.
• Comparison of model-calculated reflectance with measured data across a specific spectral range (0.50–1.10 micrometers).

Main Results:

• The models accurately predicted exchange symmetry for specular irradiance with respect to sun and observer angles for both cotton and wheat.
• Discrepancies were observed between model calculations and experimental data for wheat reflectance as a function of sun angle.
• Fair agreement was found between model predictions and wheat measurements for specular reflectance in the 0.50–1.10 micrometer range.

Conclusions:

• Suits' models demonstrate good predictive capability for angular symmetry in plant canopy reflectance.
• Further refinement of the models may be needed to accurately capture variations in wheat reflectance with sun angle.
• The study provides essential physical and optical parameters for wheat to facilitate the application of Suits' models.