Application of NIR hyperspectral imaging for water distribution measurements in plant roots and soil

A hyper-spectral root imaging system for the acquisition of spatially resolved near infrared (NIR) spectroscopy data of rhizoboxes has been developed and applied for research into the drought-resistance of roots. In contrast to imaging using visible light, the NIR wavelength range (1000nm to 2500nm) allows discriminating essential plant features by their unique spectral characteristics. The increased image contrast in the NIR allows roots to be directly segmented from soil and also extract additional information, e.g. basic root architecture. The water absorption bands in the NIR range can be exploited to both determine the actual water content and estimate the age of the roots. The paper presents the hardware setup of the hyper-spectral root imaging system and first results of the related target application.