Background and aimsTo test the hypothesis that dominant plant species could acquire different nitrogen (N) forms over a spatial scale and they also have the ability to compete for available N with microbes.MethodsA short-term 15N labeling experiment was conducted in the temperate grassland ecosystem of North China in July of 2013. Three N forms (NO3 ? , NH4 + and glycine) labeled with 15N were injected into the two soil depths (0–5 and 5–15 cm) surrounding each plant to explore N acquisition by plants and microbes. Three dominant plant species (Artemisia frigida, Cleistogenes squarrosa and Artemisia capillaris) were investigated.ResultsTwo hours after 15N labeling, all three dominant plant species absorbed both organic and inorganic N, but different patterns were observed at two soil depths. Uptake of NO3 ? was significantly higher at 0–5 cm than at 5–15 cm soil depth among all the dominant plant species. 15N recovery by microbes was significantly higher than plants. However, 15N recovery by plants showed different patterns over soil depths.ConclusionsDominant plant species in the temperate grassland have different patterns in acquisition of N added to soil in organic form and absorption of inorganic N, and microbes were more effectively than plants at competing for N in a short-term period. |