As forest ecosystems generally develop on poor and unfertilized soils, nutrient cycles and input/output budgets, notably in the humus compartment, are key to determining forest sustainability. Previous studies generally focused on the ecosystem scale or only on C, N, P in the humus layer. Our objectives in this study are to establish these budgets for principal elements, considering dust inputs and, for the first time, particulate outputs. To achieve these objectives, the inputs and outputs of the elements in litterfall, particulates (dust inputs and particulates in the outgoing solution) and solution were quantified in mulls in two contrasting soils in beech ecosystems monitored for 7 years. The concentrations of the elements in the particulate outputs were 3 or 16 times higher than those in dust, because some particles were produced in the humus. The input/output budgets were balanced for K, Na and S in both soils and for P, Si and Mg in one soil. These elements were transported in the humus mainly as a solution or as a soluble form in plant tissues. For Ca and Mn in both soils and for P, Si and Mg in one soil, the elements found in biominerals, the inputs were higher than the outputs, indicating that other outputs were not taken into account in this balance, such as biomineral sedimentation or uptake by fungi. These results show the importance of the humus particles in element cycles.

中文翻译：

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腐殖质浸出液中的颗粒影响山毛榉林中主要元素的投入产出预算

由于森林生态系统通常在贫瘠和未施肥的土壤上发展，养分循环和投入/产出预算，特别是在腐殖质部分，是决定森林可持续性的关键。以往的研究一般集中在生态系统规模或仅研究腐殖质层中的 C、N、P。我们在这项研究中的目标是为主要元素建立这些预算，同时考虑灰尘输入和颗粒物输出，这是第一次。为实现这些目标，在监测了 7 年的山毛榉生态系统中，在两种对比土壤中，对凋落物、颗粒物（灰尘输入和输出溶液中的颗粒物）和溶液中元素的输入和输出进行了量化。由于腐殖质中产生了一些颗粒，颗粒输出中元素的浓度比灰尘中的元素浓度高 3 到 16 倍。两种土壤中 K、Na 和 S 以及一种土壤中 P、Si 和 Mg 的输入/输出预算平衡。这些元素主要以溶液或植物组织中的可溶性形式在腐殖质中运输。对于两种土壤中的 Ca 和 Mn 以及一种土壤中的 P、Si 和 Mg，生物矿物中发现的元素，输入高于输出，表明在这种平衡中没有考虑其他输出，例如生物矿物沉淀或被真菌吸收。这些结果表明腐殖质颗粒在元素循环中的重要性。投入高于产出，表明在这种平衡中没有考虑其他产出，例如生物矿物沉淀或真菌吸收。这些结果表明腐殖质颗粒在元素循环中的重要性。投入高于产出，表明在这种平衡中没有考虑其他产出，例如生物矿物沉淀或真菌吸收。这些结果表明腐殖质颗粒在元素循环中的重要性。