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| Adsorption and desorption of NH4+-N in the different soil genesis layers in the nearshore vegetable field of Erhai Lake |
| Received:August 09, 2016 |
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| KeyWord:NH4+-N;adsorption and desorption;nearshore vegetable field of Erhai Lake;soil genesis layers |
| Author Name | Affiliation | E-mail | | CHEN An-qiang | Agricultural Environment Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650205, China | | | LEI Bao-kun | Agricultural Environment Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650205, China | | | LIU Hong-bin | Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture, Beijing 100081, China | | | ZHAI Li-mei | Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture, Beijing 100081, China | | | WANG Hong-yuan | Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture, Beijing 100081, China | | | MAO Yan-ting | Agricultural Environment Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650205, China | | | ZHANG Dan | College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, China | yidan33@163.com |
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| Abstract: |
| In order to illuminate the adsorption and desorption characteristics of NH4+-N in the different soil genesis layers of vegetable field around the Erhai Lake, the experiments of isothermal absorption/desorption were conducted and the effect of soil physicochemical properties on adsorption and desorption parameters were also analyzed. The results showed that isothermal adsorption and desorption characteristics of NH4+-N in the different soil genesis layers conformed to the Langmuir model and linear equation, respectively. Adsorption and desorption processes of NH4+-N in the different soil genesis layers were irreversibility, and there was a "hysteresis" phenomenon during the desorption process of NH4+-N. The saturated adsorption capacity Q0, equilibrium concentrations ENC0 and desorption rate of NH4+-N in the different soil genesis layers ranged from 435.597 to 982.757 mg·kg-1, from 0.370 to 0.661 mg·L-1 and from 0.281 to 0.729, respectively. The adsorption ability of NH4+-N among different soil layers was, in order of preference, A layer > P layer > W layer > G layer, while their desorption capability was contrary. Silt content, clay content and sand grade microaggregates in soil were positively correlated with Q0, the maximum buffer capacity MBC, equilibrium concentrations ENC0, and they were negatively correlated with desorption rate K3. Q0, MBC and ENC0 were positively correlated with organic matter OM, total nitrogen TN and NH4+-N, and they were negatively correlated with TFe, TMn and pH. But there were the opposite changes between K3 and chemical properties of different soil genesis layers. Above results of this study could provid valuable parameter for determining the diffusion flux of nitrogen from different soil genesis layers to Erhai Lake through shallow groundwater. |
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