Unraveling trees P sources based on the linkage of bottom up und top down approaches for P uptake modelling

基于自下而上和自上而下的磷吸收建模方法的联系来揭示树木的磷源

• 批准号: 241266589
• 负责人: Professorin Dr. Friederike Lang
• 金额: --
• 依托单位: Professur für Bodenökologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/241266589?language=en
• 关键词: Unraveling; trees; sources; based; linkage

The contribution of organic and mineral sources to the P uptake of trees is still unresolved. The hypothesis that organic sources get more important for the P nutrition of trees with decreasing P stocks of soils is in the centre of our project. Our approach of testing this is the integrative use of bottom-up and top-down approaches for the modelling of the P uptake by trees. The joint SPP project provides unique opportunities to follow this approach. Phosphorus requirements of old-grown beech forests will be assessed performing top-down modelling based on growth data and litter production. The bottom-up model will provide the potential uptake of the root system based on the absorbing root surface and the potential supply from mineral and organic sources. The assessment of the specific root length will be combined with the measurement of extramatrical hyphae by (micro)morphological methods using reflecting microscopy. The analyses of P-mobilization kinetics will be performed using diffusive gradients in thin films (DGT) at low soil temperatures (only inorganic P) and warm soil temperature (inorganic and organic P). The data will then be fitted to a kinetic process model. Specific effects by exudation of carboxylates and synergisms of root networks, and the effect of soil moisture will be assessed by microdialysis. Variability of P availability that can be related to soil structure will be assessed by the fractionation of soil aggregates. The different working packages of our project will provide relevant knowledge on the processes controlling P uptake at the study sites. In addition our approach will link soil and plant analyses and will help synthesize manifold data related to P mobilization and plant uptake gained from the study sites. We do not expect a consistent P-budget of the contrasting forest sites, but the experiments and the combination of the different model approaches will serve as a framework for the classification of input variables regarding their sensitivity to the responding P uptake.

有机和矿物质来源对树木吸收磷的贡献仍未得到解决。有机来源对土壤磷储量减少的树木的磷营养更重要这一假设是我们项目的核心。我们的测试方法是综合使用自下而上和自上而下的方法来模拟树木对磷的吸收。战略优先事项联合项目为遵循这一办法提供了独特的机会。将根据生长数据和凋落物产量进行自上而下的建模，以评估老山毛榉森林的磷需求。自下而上的模型将根据吸收的根表面和来自矿物和有机来源的潜在供应来提供对根系的潜在吸收。比根长度的评估将与使用反射显微镜的(显微)形态方法测量菌丝外菌丝相结合。在土壤温度较低(只含无机磷)和土壤温度较高(无机磷和有机磷)的情况下，将利用薄膜扩散梯度(DGT)进行磷的活化动力学分析。然后将数据与动力学过程模型进行拟合。通过微透析法评估羧酸盐的渗出和根系网络的协同作用所产生的具体影响，以及土壤水分的影响。可与土壤结构有关的磷有效性的变异性将通过土壤团聚体的分级来评估。我们项目的不同工作包将提供有关研究地点磷吸收控制过程的相关知识。此外，我们的方法将把土壤和植物分析联系起来，并将有助于综合从研究地点获得的与磷动员和植物吸收有关的各种数据。我们不期望对比林地的磷收支是一致的，但实验和不同模型方法的组合将作为关于输入变量对响应的磷吸收的敏感性的分类的框架。