Modeling forest floor contribution to phosphorus supply to maritime pine seedlings in two-layered forest soils

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• 作者：Mathieu Jonard ; Laurent Augusto ; Emmanuel Hanert ; David L. Achat ; Mark R. Bakker ; Christian Morel ; Alain Mollier ; Sylvain Pellerin
• 关键词：Diffusion/mass-flow theory ; Pinus pinaster ; P retention properties ; Seedlings ; P uptake ; P nutrition
• 刊名：Ecological Modelling
• 出版年：2010
• 出版时间：24 March 2010
• 年：2010
• 卷：221
• 期：6
• 页码：927-935
• 全文大小：603 K

文摘

The quantitative contribution of the forest floor to P nutrition of maritime pine seedlings was experimentally determined by Jonard et al. (2009) in a greenhouse experiment using the radio-isotopic labeling. To extend the results of the experiment on a known mineral soil, a modeling approach was developed to predict P uptake of maritime pine seedlings growing in a mineral soil covered with a forest floor layer. The classical nutrient uptake model based on the diffusion/mass-flow theory was extended to take into account mineralization of P in dead organic matter, microbial P immobilization and re-mineralization and P leaching. In addition, the buffer power characterizing the P retention properties of the mineral soil was allowed to vary with time and with the P-ion concentration in solution. To account for increasing root competition with time, a moving boundary approach was implemented. According to the model, the forest floor contributed most of the P supply to the seedlings (99.3 % after 130 days). Predicted P uptake was consistent with observed P uptake and modeling efficiency was 0.97. The uptake model was then used to evaluate the impact of the P retention properties of the mineral soil on the contribution of the forest floor to P uptake. Simulations showed that the contribution of the forest floor was much lower in the quasi non-reactive soil (45.7 % ) but rapidly increased with soil P reactivity.