Nitrogen deposition contributes to soil acidification in tropical ecosystems

• Published in: Global change biology 2014-12, Vol.20 (12), p.3790-3801
• Main Authors: Lu, Xiankai, Mao, Qinggong, Gilliam, Frank S, Luo, Yiqi, Mo, Jiangming
• Format: Article
• Language: English
• Subjects: acid neutralizing capacity; acidification; aluminum; ammonium nitrate; Analysis of Variance; Animal and plant ecology; Animal, plant and microbial ecology; base saturation; Biogeochemistry; Biological and medical sciences; boreal forests; calcium; cation exchange capacity; China; drainage; Ecosystem; Environmental Pollutants - analysis; Environmental Pollutants - metabolism; eutrophication; exchangeable aluminum; Forest soils; forest types; Forestry; Fundamental and applied biological sciences. Psychology; General aspects; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; humid tropics; Hydrogen-Ion Concentration; leaching; Linear Models; magnesium; Models, Theoretical; neutralization; Nitrates - analysis; Nitrates - metabolism; Nitrogen; nitrogen addition; nitrogen deposition; nitrogen saturation; protons; Rainforests; Sedimentation & deposition; Soil - chemistry; soil acidification; soil buffering capacity; soil profiles; soil solution; Synecology; terrestrial ecosystems; Tropical Climate; tropical forest; tropical forests
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/gcb.12665

Elevated anthropogenic nitrogen (N) deposition has greatly altered terrestrial ecosystem functioning, threatening ecosystem health via acidification and eutrophication in temperate and boreal forests across the northern hemisphere. However, response of forest soil acidification to N deposition has been less studied in humid tropics compared to other forest types. This study was designed to explore impacts of long‐term N deposition on soil acidification processes in tropical forests. We have established a long‐term N‐deposition experiment in an N‐rich lowland tropical forest of Southern China since 2002 with N addition as NH₄NO₃ of 0, 50, 100 and 150 kg N ha⁻¹ yr⁻¹. We measured soil acidification status and element leaching in soil drainage solution after 6‐year N addition. Results showed that our study site has been experiencing serious soil acidification and was quite acid‐sensitive showing high acidification (pH₍H₂O₎