Mechanisms behind plant diversity effects on inorganic and organic N leaching from temperate grassland
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- 作者：Sophia Leimer ; Yvonne Oelmann ; Nico Eisenhauer ; Alexandru Milcu…
- 关键词：The Jena Experiment ; Biodiversity ; DON leaching ; Ammonium leaching ; TDN leaching ; Land ; use change
- 刊名：Biogeochemistry
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：131
- 期：3
- 页码：339-353
- 全文大小：
- 刊物类别：Earth and Environmental Science
- 刊物主题：Biogeosciences; Ecosystems; Environmental Chemistry; Life Sciences, general;
- 出版者：Springer International Publishing
- ISSN：1573-515X
- 卷排序：131
文摘
Higher plant diversity reduces nitrate leaching by complementary resource use, while its relation to leaching of other N species is unclear. We determined the effects of plant species richness, functional group richness, and the presence of specific functional groups on ammonium, dissolved organic N (DON), and total dissolved N (TDN) leaching from grassland in the first 4 years after conversion from fertilized arable land to unfertilized grassland. On 62 experimental plots in Jena, Germany, with 1–60 plant species and 1–4 functional groups (legumes, grasses, tall herbs, small herbs), nitrate, ammonium, and TDN concentrations in soil solution (0–0.3 m soil layer) were measured fortnightly during 4 years. DON concentrations were calculated by subtracting inorganic N from TDN. Nitrogen concentrations were multiplied with modeled downward water fluxes to obtain N leaching. DON leaching contributed most to TDN leaching (64 ± SD 4% of TDN). Ammonium leaching was unaffected by plant diversity. Increasing species richness decreased DON leaching in the fourth year. We attribute this finding to enhanced use of DON as a C and N source and enhanced mineralization of DON by soil microorganisms. An increase of species richness decreased TDN leaching likely driven by the complementary use of nitrate by diverse mixtures. Legumes increased DON and TDN leaching likely because of their N\(_{2}\)-fixing ability and higher litter production. Grasses decreased TDN leaching because of more exhaustive use of nitrate and water. Our results demonstrate that increasing plant species richness decreases leaching of DON and TDN.