Passive Microwave Study of Salt Affected Agricultural Soil

V K Gupta

Abstract


Salt affected agricultural soil from superficial horizon of local profile of Alwar region with textural composition sand=30.2%, silt=59.7% and clay=10.1% has been selected for an estimation of observable parameter of passive microwave remote sensing. Artificially salinized and moistened soil samples with different concentrations in part per million (ppm) of Sodium Chloride corresponding to 0 ppm to 35000 ppm soluble in conductivity water are prepared.The real and imaginary parts of dielectric constant ε’ and ε” for artificially moistened and salinized soil   with Sodium Chloride are determined at different levels of salinization. Real and imaginary part of dielectric constant is measured by wave-guide cell method at a single microwave frequency 9.78 GHz and at constant temperature 330C.  The Fresnel reflectivity of salinized and moistened soil is determined for different observation angles. Further, Microwave emissivity of salinized soil is also calculated with suitable model calculations in view of passive microwave remote sensing. Microwave emissivity decreases with both salinity and moistness. Effect of salinity on emissivity is very small and considerable only at higher wetness of soil. In dry soils no impact of salinity observed on emission behaviour. High dielectric contrast between emitting layer of soil and air causes more energy to reflect back within the soil media than that of transmitted out in air. Hence, emissivity of soil decreases as salinity increases. 


Keywords


Dielectric constant, Microwave emissivity, Salinization

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References


Bohrer V L, “Ethno botanical aspects of Snake town, a Hohokam village in southern Arizona” American Antiquity, 35(1970) 413-430.

Kolarkar A S, Dhir R P and Singh N “Characteristics and morphogenesis of salt-affected soils in south-eastern arid Rajasthan” Journal of Indian Society of Remote Sensing 8 (1) (1980) 31-34.

Jackson T J and O’Nell P E “Salinity effects on the microwave emission of soils,” J IEEE Trans. Geosci. Remote Sensing GE-25(1987) 214–220.

Sreenivas K, Venkataratnam L and Narasimaha Rao P V “Dielectric properties of salt- affected soils” Int J

Remote Sensing 16(4) (1995) 641-649.

Yadav J S and Gandhi J M “Simple microwave technique for measuring the dielectric parameters of solids and their powders” Indian J Pure Appl Phys 30(1992) 427–432.

Peake W H, “Interaction of electromagnetic waves with some natural surfaces” IRE Trans on Antennas and propog AP-7 (5) (1959) 2582- 2590.

Kong J. A., Electromagnetic Wave Theory, 2nd edn. Wiley-Interscience, New York. (1990).


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