Mayuri Kashyap

Terahertz Spectroscopy and Imaging in Quantitative Assessment of Plant Hydration Towards Implementing Optimized Irrigation Management in Australia and India

UN World Water Development Report predicts an increase in water demand in agricultural sector by 70-90% without improved methods to satisfy the basic feeding demand of the growing world population. Moreover, global climate change is causing steep rise in temperatures, increased temperature variability, changes in levels and frequency of precipitation, a greater frequency of dry spells and droughts and increasing intensity and frequency of extreme weather events. These problems collectively result in plant growth retardation and an overall increase in the stress level of the plants. Stressed plants become susceptible to disease, insect infestation and other maladies causing loss in both quantity and quality of the agricultural produce. Therefore, it is essential to establish a fast, accurate and a non-invasive technique for quantitative assessment of plant hydration levels. This will further help in implementing 'smart' irrigation management reducing water usage and wastage in agriculture. This project will explore spectroscopy and imaging using terahertz (THz) range (3000 - 30 µm in wavelength or 0.1 × 1012 - 10 × 1012 Hz in frequency) which is an extremely sensitive non-contact, non-invasive technique to measure hydration levels. Several representative plants having specific hydration schemes that are available both in Australia and India, such as, mango, banana and bamboo will be initially studied with broadband, THz time-domain spectroscopy and imaging set-up. Standardization protocol and calibration charts of transpirations of all plant species under study will be prepared under normal and drought conditions. In the second phase, high power THz sources working in a relatively narrow frequency range will be used to target the high-frequency THz water signature. This will result in increased image resolution required in a practical, field deployable instrument that can accurately map the water uptake and release by plants.