Different fates of deposited and in a temperate forest in northeast China: a 15N tracer study |
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| Authors: | Jun Liu Bo Peng Zongwei Xia Jianfei Sun Decai Gao Weiwei Dai Ping Jiang Edith Bai |
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| Affiliation: | 1. CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, China;2. University of Chinese Academy of Sciences, Beijing, China |
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| Abstract: | Increasing atmospheric reactive nitrogen (N) deposition due to human activities could change N cycling in terrestrial ecosystems. However, the differences between the fates of deposited  and  are still not fully understood. Here, we investigated the fates of deposited  and  , respectively, via the application of 15NH4NO3 and NH415NO3 in a temperate forest ecosystem. Results showed that at 410 days after tracer application, most  was immobilized in litter layer (50 ± 2%), while a considerable amount of  penetrated into 0–5 cm mineral soil (42 ± 2%), indicating that litter layer and 0–5 cm mineral soil were the major N sinks of  and  , respectively. Broad‐leaved trees assimilated more 15N under NH415NO3 treatment compared to under 15NH4NO3 treatment, indicating their preference for  –N. At 410 days after tracer application, 16 ± 4% added 15N was found in aboveground biomass under  treatment, which was twice more than that under  treatment (6 ± 1%). At the same time, approximately 80% added 15N was recovered in soil and plants under both treatments, which suggested that this forest had high potential for retention of deposited N. These results provided evidence that there were great differences between the fates of deposited  and  , which could help us better understand the mechanisms and capability of forest ecosystems as a sink of reactive nitrogen. |
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| Keywords: | broad‐leaved and Korean pine (Pinus koraiensis) mixed forest nitrogen deposition nitrogen fate nitrogen retention nitrogen saturation |
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and 
are still not fully understood. Here, we investigated the fates of deposited 
and 
, respectively, via the application of 15NH4NO3 and NH415NO3 in a temperate forest ecosystem. Results showed that at 410 days after tracer application, most 
was immobilized in litter layer (50 ± 2%), while a considerable amount of 
penetrated into 0–5 cm mineral soil (42 ± 2%), indicating that litter layer and 0–5 cm mineral soil were the major N sinks of 
and 
, respectively. Broad‐leaved trees assimilated more 15N under NH415NO3 treatment compared to under 15NH4NO3 treatment, indicating their preference for 
–N. At 410 days after tracer application, 16 ± 4% added 15N was found in aboveground biomass under 
treatment, which was twice more than that under 
treatment (6 ± 1%). At the same time, approximately 80% added 15N was recovered in soil and plants under both treatments, which suggested that this forest had high potential for retention of deposited N. These results provided evidence that there were great differences between the fates of deposited 
and 
, which could help us better understand the mechanisms and capability of forest ecosystems as a sink of reactive nitrogen.