Measurements of leaf water content using terahertz radiation

A novel technique for the noninvasive continuous measurement of leaf water content is presented. The technique is based on transmission measurements o f terahertz radiation with a null-balance quasi-optical transmissometer ope rating at 94 GHz, A model for the propagation of terahertz radiation throug h leaves is presented. This, in conjunction with leaf thickness information determined separately, may be used to quantitatively relate transmittance measurements to leaf water content. Measurements using a dispersive Fourier transform spectrometer in the range of 100 GHz-500 GHz using Phormium tena x and Fatsia japonica leaves are also reported.