This paper reports some results on adaptive polarization techniques for rejection of ground clutter. The analysis is based on measurements carried out with a low resolution radar equipped with a diversity polarization receiver and recorded through a suitably designed acquisition system. The polarization behavior of the recorded ground clutter phenomena is first investigated. Owing to the considerably different polarimetric features of target echoes and ground clutter, it is shown that some polarimetric processing techniques can successfully be applied to improving radar target detection performance in the presence of screening ground clutter. Two different types of ground clutter cancellers, which are able to reject undesired signals by recording and updating at each scan the polarization map of the system coverage, are considered. Some results relating to performance evaluation of such filtering techniques are reported.