Estimation of moisture in maize leaf by measuring leaf dielectric constant
2008
Afzal, A. (Isfahan Univ. of Technology (Iran). College of Agriculture) | Mousavi, S.F. (Isfahan Univ. of Technology (Iran). College of Agriculture)
Leaf moisture of maize was estimated by variation of dielectric constant. These variations are measured via designed and manufactured capacitive sensors. Capacitance was measured at two frequencies (100 kHz & 1 MHz). The results showed that in all cases the best fitted curve for variations of dielectric constant in relation to leaf moisture percentage was in the form of y=ae(bx) exponential function (y is capacitance, x is leaf moisture content, a is coefficient & b is exponent). As leaf moisture increased the dispersion of points around the line increased. Parameters `a' and `b' for different plants, different places of samples on each leaf and each frequency were not significantly different (p = 0.01). Coefficient `b' and coefficient of determination (R2) decreased from top to bottom of the plants in 100 kHz frequency. The R2 in 100 kHz frequency were higher than 1 MHz.
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