I tested the hypothesis that subterranean termites and soil microarthropods are important in the disappearance of fluff grass litter in the soil surface by an experiment designed to separate termite and microarthropod effects.... I found that the densities of microarthropods in fluff grass litter were too low to have a measurable effect on decomposition even if I assumed that the microarthropods consumed litter equivalent to their body weight each day. The sequence of microarthropod colonization differed from that reported for decomposition of buried litter and roots. I conclude that subterranean termites are the most important facto affecting fluff grass litter breakdown in the Chihuahuan Desert