The mycorrhiza-mediated pathway for soil organic matter (SOM) formation and consequences for the SOM turnover under short rotation forestry

丛枝(AM)和外生菌根(EM)真菌对土壤有机质(SOM)数量和质量的影响机制不同。到目前为止，在土地利用从耕地转变为短轮伐期林业(SRF)后，优势菌根类型的变化如何影响土壤有机质的数量、组成和周转，目前还知之甚少。因此，我们将在田间和实验室实验中操纵主要菌根类型，以检验以下假设：(1)在SRF下，从AM到EM的预期变化，由于菌丝形成和SOM稳定疏水蛋白生产，导致SOM储存；(2)SRF刺激腐殖体分解先前储存的SOM，并利用谷隆马林的聚集效应，在作物中回到AM，以分解先前储存的SOM并形成新的SOM。因此，我们将抽样最近和以前的长期SRF及其相应的参考地点。我们将研究菌根的定植、SOM的数量和分子组成，包括标志物(甲壳素、疏水素、甘露醇)。在培养实验中，将使用13C研究来研究在EM存在和不存在的情况下微生物对SOM的分解。这将证明菌根C对土壤有机质形成的重要性和可持续性。

Arbuscular- (AM) and ectomycorrhizal (EM) fungi influence soil organic matter (SOM) quantity and quality using different mechanisms. So far little is known how changes in the dominating mycorrhiza type occurring after land use change from arable crops to short rotation forestry (SRF) affect the quantity, composition and turnover of SOM. Therefore, we will manipulate the dominating mycorrhiza type in field and lab experiments to test the following hypotheses: (1) A change from AM to EM, expected under SRF, results in SOM storage due to mycelium formation and SOM stabilising hydrophobin production; (2) A back-change to AM in crops after SRF stimulates saprotrophs to decompose the previously stored SOM and forms new SOM using aggregating effects of glomalin. Accordingly, we will sample recent and former long term SRF and their corresponding reference sites. We will investigate the mycorrhizal colonisation, the amount and molecular composition of SOM including markers (chitin, hydrophobin, glomalin). The microbial decomposition of SOM in the presence and absence of EM will be investigated using 13C studies in incubation experiments. This will prove the importance and sustainability of mycorrhizal C for SOM formation.