Nonerodible elements on erodible surfaces have the effect of absorbing part of the wind momentum flux (stress) and thus protect the erodible surface to a degree, depending on the geometry of the mixture. Experiments measuring the effect of nonerodible elements show that these elements increase the apparent threshold velocity of erosion and that the functional form of the mass flux (of erodible sand particles) in terms of friction velocity follows an Owen function. The partitioning of momentum flux by the nonerodible elements is smaller in our experiments than measured in the experiments of Marshall; however, in those measurements for which nonerodible geometry is similar, our results are roughly consistent with the experimental results of Lyles et al. The disagreement with the Marshall results is tentatively explained by differences in scale and in the wind stress measuring systems.