Plant Fine-root Decomposition in Relation to Biomass Quality in a Mixed-grass Prairie Under Cattle Grazing

A modified litter-bag method was used to measure plant fineroot decomposition in relation to biomass quality in a mixedgrass prairie. Measurements were made during three years on moderately and heavily grazed pastures that had been under cattle grazing for 17 years prior to sampling. Although we found no significant difference in initial fine-root litter quality between grazing treatments, nitrogen limitation to fine-root decomposition occurred under moderate grazing but not under heavy grazing, suggesting the dominance of the carbon-limited decomposition in heavily grazed pastures as compared with the nitrogenlimited decomposition in the moderately grazed pastures. Our data and results have implications for not only shortterm nutrient release essential for plant growth, but also for long-term carbon sequestration potentials in rangelands under grazing management.