competition for N in Forest Soils: Stabilization of Organic N in Recalcitrant Pools

我们的知识在森林土壤中的N竞争是混淆不完全的理解植物，菌根真菌，土壤微生物之间的分区和固存的N到SOM。结合现场和实验室调查与15 N标记实验的方法，提出了阐明主要的竞争性长期稳定机制的有机N和DON的形成和结构。将产生的定量数据上的N转移到非微生物的，可再生的有机物池，因此，主要的长期稳定过程的相关性，通过形成单宁蛋白质复合物，有机-矿物协会和非生物N固定。固态15 N和13 C NMR光谱将提供有关单宁-蛋白质复合物中单宁的有机N，MALDI-TOF-MS结合形式的信息。化学分解技术将允许量化散装土壤和有机矿物复合物中的水解蛋白质。在研究小组的框架内，这种方法将允许区分和量化有机氮与不稳定形式的有机氮的稳定性。最后，考虑到土壤中有机氮库的形成和缓慢周转，这将提供关于植物和微生物之间的氮竞争的信息。

Our knowledge of the competition for N in forest soils is confounded by incomplete understanding of the partitioning between plants, mycorrhizal fungi, soil microbes and sequestration of N into SOM. A combined approach of field and laboratory investigations together with 15N labelling experiments is proposed to elucidate the major competitive long-term stabilization mechanisms of organic N and the formation and structure of DON. Quantitative data will be generated on the N transferred to non-microbial, recalcitrant organic matter pools and, thus, the relevance of major long-term stabilization processes via formation of tannin-protein complexes, organo-mineral associations and abiotic N immobilization. Solid-state 15N and 13C NMR spectroscopy will provide information on the binding forms of organic N, MALDI-TOF-MS on tannins in tannin-protein complexes. Chemolytic techniques will allow to quantify hydrolysable proteins in bulks soils and organo-mineral complexes. In the framework of the research group this approach will allow to differentiate and to quantify the stabilization of organic N versus the organic N present in labile forms. In the end this will provide information on the competition for N between plants and microorganisms taking into account the formation and slow turnover of recalcitrant organic N pools in soil.