Combined effects of litter features, UV radiation, and soil water on litter decomposition in denuded areas of the arid Patagonian Monte

We evaluated the combined effects of litter type, UV radiation, and soil water on litter decomposition processes in denuded areas of the arid Patagonian Monte. We conducted a manipulative experiment with litterbags with litter dominated by evergreen shrubs (ES), and litter dominated by perennial grasses and evergreen shrubs (PG) placed on undisturbed upper soil blocks from denuded areas. We subjected soil blocks with litterbags to near ambient and attenuated UV radiation levels, and low and high soil water levels. We evaluated litter mass loss and changes in N, soluble phenolic and lignin contents during 420 days. PG litter decomposed faster than ES litter, and UV radiation and soil water enhanced decomposition of both litter types. PG litter immobilized N while ES litter released N. During decomposition, soluble phenolic content decreased while lignin content did not vary in both litter types. Our results highlighted that abiotic and biotic controls differed between mass loss and N release/immobilization. We found additive effects of the studied factors on mass loss while litter chemistry controlled microbial N release or immobilization from decaying litter. Further studies should explore the effects of these factors on species or functional groups shifts in microorganism communities.