Effects of nitrogen deposition on soil nitrogen fractions and enzyme activities in wet meadow of the Qinghai-Tibet Plateau.

Soil nitrogen (N) transformation is an essential portion of the N cycle in wetland ecosystems, governing the retention status of soil N by controlling the effective soil N content. N deposition produced by human activities changes the physical characteristics of soil, affecting N fractions and enzyme activities. To characterize these influences, three different N addition levels (N5, 5 g/m; N10, 10 g/m; N15, 15 g/m) were established using a wet meadow on the Qinghai-Tibet Plateau (QTP) as a control treatment (0 g/m).