Linking land use intensity, biodiversity, soil microbial processes and organo-mineral interactions for a mechanistic understanding of Nitrogen turnover in grassland ecosystems (BE_BioMON)

将土地利用强度、生物多样性、土壤微生物过程和有机矿物相互作用联系起来，从机制上理解草原生态系统的氮周转 (BE_BioMON)

• 批准号: 512359828
• 负责人: Privatdozent Dr. Michael Dannenmann
• 金额: --
• 依托单位: Abteilung Vergleichende Mikrobiomanalysen (COMI)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/512359828?language=en
• 关键词: Linking; land; use; intensity; biodiversity

Increase in land use intensity (LUI) is a strong driver for environmental nitrogen (N) losses and decline of biodiversity and multifunctionality in grassland ecosystems. Still, interactions between LUI, above- and belowground biodiversity and N cycling in grassland ecosystems lack a mechanistic understanding, which prevents targeted mitigation measures. Through an interdisciplinary integration of soil microbial ecology, short-term processes of biotic N partitioning in the plant-soil-microbe system, and long-term physicochemical soil organic nitrogen (SON) retention pathways, BE_BioMon aims to fill this knowledge gap by linking measurements and modelling. We hypothesize that with decreasing LUI and more diverse microbiome, N partitioning shifts from nitrification/denitrification to biotic assimilation. This promotes N retention via necromass stabilization in particulate and mineral-associated SON depending on aggregate turnover and microscale soil architecture. Furthermore, we expect that increasing LUI will result in a shift from symbiotic to associative N fixation, which will increase the N2:N2O emission ratio due to truncated denitrification pathways in symbiotic diazotrophs. Moreover, we hypothesize that soil δ15N is fingerprinting LUI effects on N cycling, and thus can serve as a process integrating benchmark quantity for ecosystem models. This is expected to advance modeling-based spatiotemporal scaling of LUI effects on grassland N cycling. To test the hypotheses, we will perform field 15N fertilizer tracing experiments at selected plots of different LUI at all 3 Biodiversity Exploratories (BE) (WP1). In WP2, we will conduct mesocosm experiments with 15N2 exposure to disentangle LUI effects on the fates of BNF-N. WP3 is designed to fingerprint N cycling within the BE soil sampling campaign at all grassland EPs through vertical δ15N soil profiles, metagenomics, and SON fractionation. The gained knowledge from experimental work of WP1-3 and already available BExIS data will be used for testing and advancing N routines of the process-based ecosystem model LandscapeDNDC. This model, expanded by a dynamic vegetation model CoSMo, is used to evaluate differences in N cycling across the entirety of BE grassland plots (WP4). In WP5 (synthesis) we will mechanistically link effects of LUI and biodiversity with measured and modeled biogeochemical N transformations, N retention through organo-mineral interactions and full N balances at scales from days to years. We expect that this synthesis finally allows for an advanced mechanistic and functional understanding of ecosystem N cycling as influenced by LUI, above- and belowground biodiversity and site-specific properties.

土地利用强度（LUI）的增加是环境氮损失（N）损失的强大驱动力，以及在草地生态系统中生物多样性和多功能性的下降。尽管如此，LUI，生物多样性和低于生物多样性和N循环的相互作用缺乏机械理解，这阻止了针对性的缓解测量。通过跨学科微生物生态学的跨学科整合，植物土壤 - 微生物系统中生物N分配的短期过程以及长期的物理氮（SON）保留途径，BE_BIOMON旨在通过链接测量和建模来填补这一知识差距。我们假设随着LUI和更多的潜水微生物组的降低，从硝化/反硝化转向生物同化。这通过颗粒物和矿物相关的儿子在颗粒状和微观土壤结构中促进n保留newention。此外，我们预计LUI的增加将导致从共生到联想n固定，这将增加由于共生重生噬菌体中截短的非硝化途径而导致的N2：N2O发射率。此外，我们假设土壤δ15N对n循环有LUI的影响，因此可以用作整合生态系统模型基准数量的过程。预计这将推进基于建模的时空缩放LUI对草原n循环的影响。为了检验假设，我们将在所有3种生物多样性探索（BE）（WP1）的不同LUI图的选定图上进行15N肥料追踪实验。在WP2中，我们将进行15N2暴露于BNF-N命运的15N2暴露于LUI影响的中验实验。 WP3旨在通过垂直Δ15N土壤剖面，宏基因组学和儿子分馏，在所有草地EPS的BE土壤采样运动中循环。从WP1-3的实验工作中获得的知识，并且已经可用的BEXIS数据将用于测试和推进基于过程的生态系统模型Landscapedndc的N例程。该模型通过动态植被模型COSMO扩展，用于评估整个BE GARD BEARLAND地块（WP4）中N循环的差异。在WP5（合成）中，我们将从机械上将LUI和生物多样性的效应与经过测量和建模的生物地球化学N变化，通过有机矿物质相互作用保持N n reention留，并在数天到几天的尺度上保持全平衡。我们预计，这种综合最终允许对生态系统N循环的高级机械和功能理解，受LUI，地下生物多样性和特定地点特定特性的影响。