The precipitation of sparingly soluble calcium phosphate in calcareous soils decreases the bioavailability of macronutrients, which makes their addition by way of fertilisers necessary. Sludge resulting from treating urban wastewater does not only provide significant amounts of phosphorus, but also helps lower the pH, thus increasing its bioavailability. The loss of part of soil nutrients due to irrigation or rain can contaminate groundwater. In order to assess the movement of phosphorus, a experiment was conducted on percolation columns, to which different doses of wastes were applied. The pH decreased by as much as 0.89 units, as well as the assimilable and soluble P, in intervals of 20 cm of depth, obtaining maximum values of 254 mg P kg⁻¹ and 1455 μg P kg⁻¹ respectively, and the P present in the leached water collected, which did not surpass 95 μg PL⁻¹. The intent was to learn which was the majoritarian inorganic formed crystalline phase that immobilised the movement of phosphorus through the percolation column. The results obtained by the diffraction of X-rays are not conclusive, although they point to the formation of octacalcium phosphate. The diffractograms of the studied samples have similar diffraction lines to those of apatites.

钙质土壤中微溶性磷酸钙的沉淀会降低大量营养素的生物利用度，这使得它们必须通过肥料添加。城市废水处理产生的污泥不仅提供大量磷，还有助于降低 pH 值，从而提高其生物利用度。由于灌溉或雨水造成的部分土壤养分流失会污染地下水。为了评估磷的运动，在渗透柱上进行了一项实验，在该柱上施加了不同剂量的废物。在 20 cm 深度的间隔内，pH 降低多达 0.89 个单位，可同化和可溶的 P 也降低，最大值为 254 mg P kg ^-1和 1455 μg P kg ^-1分别，收集的浸出水中存在的P不超过95μg PL ^-1。目的是了解哪个是多数主义无机形成的结晶相，它固定了磷通过渗滤柱的运动。通过 X 射线衍射获得的结果不是决定性的，尽管它们指向磷酸八钙的形成。所研究样品的衍射图具有与磷灰石相似的衍射线。