Employing the first-order Mueller matrix solution of vector radiative transfer equation for one layer of small random spheroids, simulated measurements of high-order co-polarized and cross-polarized backscattering are obtained. Iterative inversion of the dielectric constant of small spheroids and the number of particles per unit area is developed. The inversion from simulated and real AirSAR data and its dependencies upon the parameters and the random noise are discussed.