title: Effects of atmospheric deposition nitrogen flux and its composition on soil solution chemistry from a red soil farmland, southeast China.
abstract: A detailed study on the solution chemistry of red soil in South China is presented. Data are collected from two simulated column-leaching experiments with an improved setup to evaluate the effects of atmospheric N deposition (ADN) composition and ADN flux on agricultural soil acidification using a (15)N tracer technique and an in situ soil solution sampler. The results show that solution pH values decline regardless of the increase of the NH4(+)/NO3(-) ratio in the ADN composition or ADN flux, while exchangeable Al(3+), Ca(2+), Mg(2+), and K(+) concentrations increase at different soil depths (20, 40, and 60 cm). Compared with the control, ADN (60 kg per ha per year N, NH4(+)/NO3(-) ratio of 2 : 1) decreases solution pH values, increases solution concentrations of NO3(-)-N, Al(3+), Ca(2+) and Mg(2+) at the middle and lower soil depths, and promotes their removal. NH4(+)-N was not detected in red soil solutions of all the three soil layers, which might be attributed to effects of nitrification, absorption and fixation in farmland red soil. Some of the NO3(-)-N concentrations at 40-60 cm soil depth exceed the safe drinking level of 10 mg L(-1), especially when the ADN flux is beyond 60 kg ha(-1) N. These features are critical for understanding the ADN agro-ecological effects, and for future assessment of ecological critical loads of ADN in red soil farmlands.
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China. zhoujing@issas.ac.cn cuijian@cigit.ac.cn and Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Cui
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China. zhoujing@issas.ac.cn cuijian@cigit.ac.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Division of Environment, Faculty of Engineering, University of Nottingham Malaysia Campus, Semenyih, 43500, Malaysia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Chan
authors.affiliation: Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529-0126, USA.
authors.forename: Jingdong
authors.initials: J
authors.lastname: Mao
mesh_terms: D000383:Agriculture; D001272:Atmosphere / Q000737:chemistry; D002681:China; D017753:Ecosystem; D004784:Environmental Monitoring; D009566:Nitrates / Q000032:analysis; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D009566:Nitrates; D012987:Soil; D012989:Soil Pollutants; D009584:Nitrogen