Many ecosystems, including grassland, forest, alpine, and desert, have shown responses to N enrichment. These responses vary considerably but include changes in soil respiration rates, enzyme activities, and microbial community structure. Surprisingly, little work has examined the effects of N enrichment on soil communities and processes in agricultural systems despite the high rates of N applied in most crop production systems. We investigated litter decomposition rates and their relationship to soil communities in replicated corn-soybean-wheat rotations receiving three levels of N (0, 134, and 291 kg/ha). We found that N fertilizer resulted in modest and temporally variable increases in the activity of four C and N cycle enzymes and modest changes in microbial community structure. We also found that N fertilizer increased mesofaunal abundance by >30% in September but not at other times of the year. There were no differences in the decomposition rates of either corn or wheat. We are in the process of determining whether litter chemistry or soil respiration rates were altered by N fertilization. Our results, although still coming in, suggest that N fertilization in agricultural systems can alter soil communities. However, we see little evidence that these changes, at least in the short-term, modify litter decomposition rates or soil C dynamics.