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

Forests

Yanmei Xiong²  Xingliang Xu⁵  Hui Zeng³  Huimin Wang⁵  Fusheng Chen¹  Dali Guo⁵  Dale W. Johnson⁴ 

[1] College of Forestry, Jiangxi Agricultural University, Nanchang, 330045, China; E-Mail:;Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China;Key Laboratory for Cyclic Economy, School of Urban Planning and Design, Shenzhen Graduate School, Peking University, Shenzhen 518055, China; E-Mail:;id="af1-forests-06-02387">1Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, Chi;Qianyanzhou Ecological Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; E-Mails:

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

DOI  :  10.3390/f6072387

来源: mdpi

【 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 in N retention.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.