Effect of Chemical Fertilizers on Dielectric Properties of Soils at Microwave Frequency

Fertilized black soil samples are prepared by mixing desired amounts of fertilizers in the black soils having 10% gravimetric moisture content. Two black soil samples were collected from two different locations of Maharashtra State (India). Three different chemical fertilizers viz., Urea, Di-Ammonium Phosphate and Potash are used. Measurements of complex dielectric constants of these soil samples have been carried out at C-band microwave frequency 4.6 GHz by using waveguide cell method. The average values of dielectric constant and dielectric loss of two unfertilized moist black soil (10% MC) samples at frequency 4.6 GHz are 7.6 and 0.43 for sample A and 9.6 and 0.38 for Sample B, respectively. The variation in values of dielectric constant and dielectric loss of these moist black soil samples mixed with different fertilizer contents are then measured at fixed frequency 4.6 GHz. The concentrations of fertilizers in the soil samples are varied over a range from 0 to 0.12 %. The dielectric constant and dielectric loss are found to increase with increase in fertilizer contents. Out of these three fertilizers, relative increase in dielectric properties is found highest for Urea and lowest for Potash. Other electric parameters such as a. c. conductivity () and relaxation time () also show increase in their values with respect to increase in the fertilizer concentrations. The physical and chemical properties of the black soil samples are also provided. Possible applications and extensions of this study are also outlined.