ABSTRACT

Phosphorus (P) losses from clay soils can be mitigated by introducing measures for improving soil structure. These include structure liming, where a mixture of CaO or Ca(OH)₂ and CaCO₃ is added to the soil. In a field experiment with separately tile-drained plots on a clay loam in Sweden, we examined the effects of structure liming on leaching of total-P, phosphate P (PO₄-P) and total nitrogen (N) during three years after initial application. The treatments included two application rates (8 and 16 t ha⁻¹) of a common product in comparison with a control (no lime). Effects of structure liming emerged during the second and third year after application, with 45 and 38% lower total-P leaching than in the unlimed control. A significant effect of the application rate was found in the third year. Nitrogen leaching and crop yield were not affected. As expected, soil pH raised following structure lime addition. Measurements of aggregate stability did not confirm the reduction in P leaching, indicating that it is important to measure P concentrations in drainage water directly when assessing the effect of structure liming.

摘要

通过引入改善土壤结构的措施，可以减轻粘土中的磷 (P) 损失。这些包括结构石灰，其中将 CaO 或 Ca(OH) ₂和 CaCO ₃的混合物添加到土壤中。在瑞典的粘土壤土上进行了单独瓷砖排水的田间试验，我们检查了结构石灰在初始后三年内对总磷、磷酸盐 P (PO ₄ -P) 和总氮 (N)浸出的影响。应用。处理包括两种施用率（8 和 16 t ha ^-1) 与对照（无石灰）相比的普通产品。结构石灰的影响在施用后的第二年和第三年出现，总磷浸出量比未加石灰的对照分别降低 45% 和 38%。在第三年发现应用率的显着影响。氮淋失和作物产量不受影响。正如预期的那样，添加结构石灰后土壤 pH 值升高。骨料稳定性的测量并未证实 P 浸出的减少，这表明在评估结构石灰的影响时，直接测量排水中的 P 浓度非常重要。