Nutrient supply as driver of biomass production and associated ecosystem water fluxes along a land-use and climate gradient

养分供应作为生物量生产和相关生态系统水通量沿土地利用和气候梯度的驱动因素

• 批准号: 395659460
• 负责人: Professor Dr. Wolfgang Wilcke
• 金额: --
• 依托单位: Institut für Geographie und Geoökologie (IFGG)
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/395659460?language=en
• 关键词: Nutrient; supply; driver; biomass; production

The Research Unit RESPECT has combined a hydrological, a dynamic vegetation, and a climatological model into the novel “biodiversified” Land Surface Model HUMBOL-TD. HUMBOL-TD allows for addressing the effect of trait diversity of trees on biomass production and associated evapotranspiration in land-use and climate change scenarios for the humid tropical montane forest in Ecuador. Subproject A3 has helped implementing N and P cycle modules, which improved projections of the dynamic vegetation module considerably. In Phase II of RESPECT, the study area will be expanded from the humid to the dry tropical montane forest. Subproject A3 will keep its focus on nutrient supply by mineralization and weathering to provide necessary data from the dry forest for model forcing (N and P deposition, soil texture, soil depth, soil water-holding capacity, C, N, and P availability) and for model evaluation (C and N concentrations, N mineralization rates, nutrient leaching). Subproject A3 will investigate the influence of land use (native montane dry forest and agroforestry) and climate (approximated by the elevations 600 and 1200 m above sea level) on N mineralization, nutrient release by weathering, microbial P retention and nutrient leaching on the 12 core plots of RESPECT in the dry forest. We will determine nutrient deposition and leaching in the dry forest with the help of ion-exchange resin cores and provide basic soil properties including C, N and P availability. We will determine N mineralization rates with a short-term incubation at the beginning and during the high rainy season and by measuring the vertical distribution of delta13C values and C concentrations in soil. We will quantify weathering rates by using open-system mass balances, with a pHstat approach (i.e., accelerated weathering at constant pH in the laboratory), and by measuring the vertical distribution of stable Ca isotope ratios in soil. We will assess the depth of nutrient uptake by the trees at the beginning and during the high rainy season with tracer experiments. Moreover, we will use a novel 18O-labeling approach to determine the degree of microbial P incorporation on all 30 core plots of RESPECT in the humid and dry study regions. All data will be provided at the core plot and plant functional type levels and part of the data even for individual target plants thereby contributing to the joint Response-Effect Framework analysis. Overall, Subproject A3 will deepen our understanding of the effects of climate and land-use change on major nutrient supply and loss processes in the humid and seasonal forms of a highly biodiverse, remote tropical montane forest and its anthropogenic replacement systems.

该研究单位将水文、动态植被和气候模型结合到新的“生物多样性”陆面模型HUMBOL-TD中。HUMBOL-TD可以解决厄瓜多尔潮湿热带山地森林土地利用和气候变化情景中树木性状多样性对生物量生产和相关蒸散的影响。次级项目A3帮助实施了氮和磷循环模块，大大改进了动态植被模块的预测。在第二阶段，研究区域将从潮湿的热带山地森林扩大到干燥的热带山地森林。分项目A3将继续侧重于矿化和风化的养分供应，为模型强迫（N和P沉积、土壤质地、土壤深度、土壤持水能力、C、N和P可用性）和模型评估（C和N浓度、N矿化率、养分沥滤）提供来自干旱森林的必要数据。分项目A3将调查土地利用（天然山地干林和农林复合）和气候（海拔600和1200米）对干旱森林中的12个CNOECT核心地块的氮矿化、风化释放养分、微生物磷保持和养分淋溶的影响。我们将在离子交换树脂芯的帮助下确定干旱森林中的养分沉积和淋失，并提供基本的土壤特性，包括C、N和P的可用性。我们将确定氮矿化率与短期孵化在开始时，在高雨季，并通过测量三角洲13 C值和C浓度在土壤中的垂直分布。我们将通过使用开放系统质量平衡和pHstat方法（即，在实验室恒定pH加速风化），并通过测量稳定的Ca同位素比值在土壤中的垂直分布。我们将评估树木在雨季开始和高雨季期间的养分吸收深度的示踪实验。此外，我们将使用一种新的18 O-标记的方法来确定微生物P掺入的程度上的所有30个核心地块的CNOECT在潮湿和干燥的研究区域。所有数据将在核心地块和植物功能类型水平上提供，部分数据甚至针对单个目标植物，从而有助于联合响应-效应框架分析。总体而言，分项目A3将加深我们对气候和土地使用变化对生物多样性高的偏远热带山地森林及其人为替代系统的潮湿和季节性主要养分供应和损失过程的影响的理解。