The function of the hyphosphere in carbon and nutrient partitioning between plants and microorganisms in grassland soils under different land-use intensities

草原土壤微生境尺度的过程可以解释更大尺度上生态系统功能的变化。在最后一个阶段，我们证明了真菌是草原土壤矿化圈和根际之间碳和养分的重要传递者。在下一阶段，我们要阐明的具体重要性hyphosphere（菌丝周围的无根土壤）在田间条件下使用新开发的HYPHobox。我们将把根际和腐殖土从根际分离出来。使用两个13 C标记的方法，一个标记的CO2，其他标记的植物残留物，我们将测试土地利用强度（LUI）是否影响碳流从植物到根际和hyphospheres，营养流从hyphospheres到根际，分别。问题是，是否互利丛枝菌根（AMF）或自由生活的腐生性真菌将占主导地位的最初的C吸收的处理和快速通道的根沉积物到hyphosphere。根际微生物也可以作为碎土和根际之间的碳和营养桥梁。新建立的多草地土地利用实验将使我们有机会调查草地土地利用的去集约化将在多大程度上以及以多快的速度改变土壤微生物的生物量和功能。减少养分供应（减少施肥，土壤微生物的直接反应）或减少割草强度（植物输入到土壤中的变化，土壤微生物的间接反应）将使我们能够解开这两个不同的机制，并将提高我们的机械理解草地农业生态系统的响应土地利用强度的变化。对150个草地站点的土壤微生物特性进行长期监测（继续2011年，2014年和2017年），将使我们能够将土地利用强度的短期变化（三年以上）与这些站点的长期历史（遗留效应）对微生物群落的功能和组成的影响区分开来。

Processes at the micro-habitat scale in grassland soils may explain changes in ecosystem functions at larger scales. In the last phase we demonstrated that fungi are important transmitters of carbon and nutrients between the mineralosphere and the rhizosphere in grassland soils. In the next phase we want to elucidate the specific importance of the hyphosphere (root-free soil around hyphae) under field conditions using newly developed HYPHOboxes. We will separate the rhizosphere and detritusphere from the hyphosphere. Using two 13C-labelling approaches, one with labelled CO2, the other with labelled plant residues, we will test whether land-use intensity (LUI) influences carbon flow from plants into the rhizo- and hyphospheres, and nutrient flow from the hyphosphere into the rhizosphere, respectively. The question is whether mutualistic arbuscular mycorrhizal (AMF) or free-living saprotrophic fungi will dominate the initial C uptake by processing and rapid channelling of rhizodeposits into the hyphosphere. Hyphosphere microorganisms may also act as carbon and nutrient bridges between the detritusphere and the rhizosphere. The newly established multi-grassland land-use experiments will give us the opportunity to investigate to what degree and how quickly de-intensification of grassland land-use will modify biomass and function of soil microorganisms. The reduction in nutrient supply (reduction of fertilization, direct response of soil microorganisms) or the reduced mowing intensity (changes in plant input into soils, indirect response of soil microorganisms) will allow us to disentangle the two different mechanisms and will improve our mechanistic understanding of the response of grassland agroecosystems to changes in land-use intensity. Long-term monitoring of soil microbial properties in 150 grassland sites (in continuation of 2011, 2014 and 2017) will enable us to disentangle short-term changes (over three years) in land-use intensity from longer-term history of the sites (legacy effects) on the functioning and composition of microbial communities.