There is considerable interest in the applicability of the model developed by Meentemeyer (1978), which predicts decomposition as a function of actual evapotranspiration (AET) and lignin, to environments other than forests. Whitford et al. (1981b) discussed exceptions to the Meentemeyer AET model in deserts and clearcut forests and concluded that in these environments, biological activity of soil microarthropod and termites, accounts for the deviations (higher rates) from the model. We recently completed a study of decomposition in a semiarid desert-grassland transitional area that provides another independent test of the AET model.