Processes of belowground carbon cycling in the plant-mycorrhiza-soil system as affected by silvicultural management

有了这个扩展建议，我们想要完成我们对地下碳循环控制过程的研究。在天然林中，我们比较了不同功能类型的树木在植物-土壤-大气系统中的碳分配情况，包括巴豆、三叶胡杨和山李。在营林试验中，我们将重点放在常规管理和集约化推广下的卢斯柏林。在全树13C标记后，标记的碳将在树叶、韧皮部汁液、根及其伴生微生物以及土壤和土壤物理部分中被追逐一年。这将允许比较研究从植物到菌根和土壤的新近同化物的通量，以及返回大气的通量，包括自养和异养土壤呼吸的分离。作为一个独立的方法，有机碳从植物到土壤的转移，其在土壤中的周转，以及土壤二氧化碳外流的来源也将通过14C方法进行研究，包括自然丰度和来自14C的炸弹。我们期望从结果中获得关于土壤中植物-土壤有机碳循环和储存的重要信息，以及由于日益退化而导致的不同功能类型树木转移的后果。对于营林小区，可以预见间伐对碳分配和土壤碳储量的影响的重要信息。

With this extention proposal we want to finalize our studies on processes controlling the belowground carbon cycling. In the natural forest, we are comparing carbon allocation in the system plant-soil-atmosphere for different functional types of trees, including Croton macrostachyus, Podocarpus falcatus, and Prunus africana. Within the silvicultural experiments we are focusing on Cupressus lusitanica stands under conventional management and intensive promotion. After whole tree 13C labelling, the labelled carbon will be chased for one year in the leaves, phloem sap, roots and associated microorganisms, and soil and physical soil fractions. This will allow to comparatively investigating the flux of recent assimilates from the plant to the mycorrhiza and soil, and back to the atmosphere, including the separation of autotrophic from heterotrophic soil respiration. As an independent approach, organic carbon transfer from plant to soil, its turnover in the soil, and the source of soil CO2 efflux will be also studied by the 14C approach, including natural abundance and the ‘bomb’ derived 14C. We expect from the results important information on plant-soil organic carbon cycling and storage in soil, and on the consequences of the shift of different functional types of trees due to increasing degradation. For the silvicultural plots, important information on the impact of thinning on the carbon allocation and soil carbon storage can be foreseen.