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对取自德国Solling的挪威云杉林的不同枯枝落叶层样品进行了一系列浸提实验 ,结果表明 ,枯落物分解程度、水∶物的比值和浸提液pH值都是元素浸提的主要控制因素。多数阳离子的浸提受到H+交换机制的很大影响 ,较低的pH值会导致较高的浸提量 ;而较高的pH值和稀释作用导致的pH值升高会导致较低的浸提量。在水∶物的比值增加到某一数值之前 ,水∶物的比值增加会导致浸提液内元素浓度与枯落物元素含量的新平衡 ,并导致浸提量增大。另外一方面 ,水∶物的比值增加导致的pH值升高会成为新的限制因素 ,导致较低的浸提量 ,尤其对于 2、3价阳离子。这两种作用机制的复合效应使浸提量与水∶物的比值的关系曲线非常复杂。建立了森林枯枝落叶层元素含量 (T ,μmol(+ )·kg- 1)、浸提液pH值、水∶物的比值 (W ,kg·kg- 1)对元素浸提量 (Y ,μmol(+ )·kg- 1枯落物 )影响的数学模型。对Na+、K+,Ca2 +、Mg2 +、Mn2 +、Al3+和Fet,模型为Y =A + (T -A)·exp(-B·pH) / [1+C·exp(-W) ];对H+,模型为Y =a +bW c。对严重酸化的枯枝落叶层元素的浸提 ,不存在所期盼的最优水∶物的比值。水∶物的比值较低时 ,元素浓度比值变化较大 ;在水∶物的比值较高时 ,元素数量比值变化较大。但对严重酸化的枯枝落叶层元素进行浸提时 ,可把?
A series of leaching experiments were carried out on different litter layer samples of Norway spruce forest from Solling, Germany. The results showed that the degree of litter decomposition, the ratio of water to material and the pH value of the extract were all elemental leaching The main control factor. The leaching of most cations is greatly influenced by the H + exchange mechanism, with lower pH leading to higher leaching; higher pH and diluting pH results in lower leaching the amount. Before the water: matter ratio increases to a certain value, an increase in the water: matter ratio results in a new balance of elemental concentrations in the leachate and litter element content, leading to an increased extraction. On the other hand, an increase in the pH value due to an increase in the water: material ratio is a new limiting factor, resulting in lower leaching rates, especially for the 2,3-valent cation. The combined effect of these two mechanisms of action makes the relationship between the extraction volume and the water: material ratio very complex. (T, μmol (+) · kg-1), the pH value of extract, the ratio of water to material (W, kg · kg- μmol (+) · kg-1 litter). The model is Y = A + (T -A) · exp (-B · pH) / [1 + C · exp (-W)] for Na +, K +, Ca2 +, Mg2 +, Mn2 +, Al3 + and Fet; For H +, the model is Y = a + bW c. The extraction of severely acidified litter layer elements does not have the optimum ratio of water to material expected. When the ratio of water to matter is low, the ratio of element concentration changes greatly; when the ratio of water to matter is high, the ratio of element to element varies greatly. However, the heavily acidified litter layer elements can be extracted when?