Effects of different forms of N deposition on leaf litter decomposition and extracellular enzyme activities in a temperate grassland

Despite the importance of decomposition for biogeochemical cycles, it is still not clear how this process is affected by different forms of nitrogen (N). Equal amounts of N with different ratios of inorganic N: organic N (0 : 0, 10 : 0, 7 : 3, 5 : 5, 3 : 7, and 0 : 10) were added to the soil in a steppe. We studied the response of litter decomposition to different forms of N enrichment. The treatment with 30% organic N resulted in the fastest decomposition, which was higher than with inorganic N or organic N addition alone. Our results highlight the need for studies of N deposition on carbon cycles that consider different components in N deposition.