Low Nitrogen Retention in Soil and Litter under Conditions without Plants in a Subtropical Pine Plantation

Forests

卷:6

Fusheng Chen¹  Hui Zeng²  Dali Guo³  Xingliang Xu³  Huimin Wang³  Yanmei Xiong⁴ 

[1] College of Forestry, Jiangxi Agricultural University, Nanchang, 330045, China;

[2] Key Laboratory for Cyclic Economy, School of Urban Planning and Design,Shenzhen Graduate School, Peking University, Shenzhen 518055, China;

[3] Qianyanzhou Ecological Station, Key Laboratory of Ecosystem Network Observationand Modeling, Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences, Beijing 100101, China;

[4] Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China;

关键词: 15N tracer;    added N interaction;    N deposition;    N addition;    priming effect;   

DOI  :  10.3390/f6072387

来源: DOAJ

【 摘 要 】

Soil acts as a major sink for added nitrogen (N) in forests, but it remains unclear about the capacity of soil to immobilize N under conditions without plant roots and whether added N interacts with ecosystem N to affect N retention. We added 15NH415NO3 to in situ soil columns (with leaching) and leaf litter (without leaching) of two tree species in a subtropical Pinus elliottii plantation. Soil and litter were collected three or eight months after N addition to measure concentrations of indigenous and exogenous N. About 70% of exogenous N was retained in soil three months after N addition, of which 65.9% were in inorganic forms. Eight months after N addition, 16.0% of exogenous N was retained in soil and 9.8%–13.6% was immobilized in litter. N addition increased the mineral release and nitrification of soil indigenous N. Loss of litter indigenous N was also increased by N addition. Our results suggest that N deposition on lands with low root activities or low soil carbon (C) contents may lead to increased N output due to low N immobilization. Moreover, the effects of added N on ecosystem indigenous N may decrease the capacity of soil and litter inN retention.

【 授权许可】

Unknown