AbstractPhosphate diffusion coefficients (De) were determined by the quantity of P that diffused from a soil block with P addition into a soil block without P addition. To compare the results with theoretical concepts and to quantify the influencing factors, Dewas also calculated using the equation ofNye(1968). This equation takes into account the P diffusion coefficient in water, D1, the volumetric water content, θ, the impedance factor, f, and the buffer power, b, of the soil. The results show that Destrongly depends on volumetric water content whereas the effect of bulk density on Devalues was relatively small. If the weighted average buffer power was used, calculated Devalues were in good agreement with measured values at higher soil moisture contents. At θ<0.22 g cm−3the measured values for Dewere smaller than the calculated. This effect is attributed to incomplete contact between the two soil blocks. The only small influence of bulk density on Deis caused by the fact that bulk density affects both θ and b in a way which compensates each o
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机译:摘要磷酸盐扩散系数(De)由添加P的土块扩散到不添加P的土块扩散的量决定。为了将结果与理论概念进行比较并量化影响因素,Dewas还使用Nye(1968)的方程进行了计算。该方程考虑了土壤的 P 扩散系数 D1、体积含水量 θ、阻抗因子 f 和缓冲功率 b。结果表明:Destrong依赖于体积含水量,而容重对Devalue的影响相对较小。如果使用加权平均缓冲功率,则计算出的贬值值与土壤含水量较高时的测量值非常吻合。在θ<0.22 g cm−3时,De的测量值小于计算值。这种影响归因于两个土块之间的不完全接触。堆积密度对 Deis 的唯一微小影响是由于堆积密度以补偿每个 o 的方式影响 θ 和 b
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