There is a strong interest in assessing the potential of space-based monitoring and mapping of state variables that are critical to hydrological and agricultural applications. Our study consists of the acquisition of ASAR imagery in single and alternating polarization modes and at different incidence angles over the Campidano plain in south-central Sardinia (Italy), the island's most important agricultural region. In tandem to image acquisition, ground data (surface soil moisture and roughness) is being collected. The project will investigate soil moisture dynamics and detection at both the large scale (multitemporal analysis for the Campidano region) and the small scale (retrieval algorithms tested on individual field plots). This paper will focus mainly on the field scale work, where ground data and imagery from the period Jun-Nov 2005 have been used to assess a semi-empirical model for surface soil moisture and roughness inversion from the radar signal.