Estimations of Water Use Efficiency in Winter Wheat Based on Multi-Angle Remote Sensing

Area of Science:

• Agricultural remote sensing
• Plant physiology
• Precision agriculture

Background:

• Accurate, real-time monitoring of water use efficiency (WUE) in winter wheat is crucial for variety selection and water resource management.
• Multi-angle remote sensing offers enhanced canopy information compared to vertical observations, improving the estimation of crop biophysical and chemical indicators.

Purpose of the Study:

• To develop a robust remote sensing model for non-destructive, real-time monitoring of wheat WUE.
• To identify optimal spectral parameters and observation angles for WUE estimation.
• To introduce a novel index for improved WUE monitoring across various conditions.

Main Methods:

• Conducted 4-year field experiments with three wheat varieties under varied water and nitrogen regimes.
• Collected multi-angle spectral reflectance data and measured wheat WUE at different growth stages.
• Developed and validated a new index, the water efficiency index (WEI = NDDAig/FWBI), for WUE monitoring.

Main Results:

• Backward observation angles proved superior to forward angles for WUE estimation.
• Established quantitative relationships between spectral parameters (Lo, NDDAig) and WUE, noting saturation issues.
• The novel WEI demonstrated higher sensitivity to WUE changes and wider angle adaptation compared to traditional indices, achieving R² of 0.685 in validation.

Conclusions:

• The developed water efficiency index (WEI) provides a more sensitive and adaptable method for monitoring wheat WUE than existing spectral parameters.
• This research has significant implications for designing and configuring remote sensing systems (satellite and UAV) for precision agriculture.
• The WEI facilitates improved crop management strategies and efficient water resource allocation in winter wheat production.