The Pampa’s rangeland in South America is underused or replaced by annual crops or forest cultivation with higher economic returns. Our goal was to test the long term effects of phosphorus fertilizer and limestone applications on P availability, aluminum neutralization in deep soil layer and rangeland productivity. For this, three rates of three phosphorus sources combined with limestone were applied in a 21 year field trial. The dry matter (between 2016 and 2019) and nutrient accumulation in plant shoot were measured. The topsoil was divided in four layers (0–2.5, 2.5–5.0, 5.0–7.5, and 7.5–10.0 cm), and chemical properties were determined. Rock phosphate application at rate 249 kg ha⁻¹ of P increased the soil P content along the soil profile down to 7.5 cm. After 21 years of liming, the neutralizing front reached depths greater than 10 cm and the reacidification was not significant. In these conditions, the contents of exchangeable Ca, Mg and Al and pH are greater than, and Al saturation is lower than without limestone. The effect of fertilization and limestone amendments are however limited in time and there was no response of rangeland dry matter production after more than four years after the last fertilization.

南美洲潘帕（Pampa）的牧场未被使用或被具有较高经济效益的一年生作物或森林种植所取代。我们的目标是测试磷肥和石灰石施用对磷的有效性，深层土壤中铝的中和和牧场生产力的长期影响。为此，在一项为期21年的田间试验中采用了三种比率的三种磷源与石灰石的组合。测量了植物茎中的干物质（2016年至2019年）和养分积累。表土分为四层（0–2.5、2.5–5.0、5.0–7.5和7.5–10.0 cm），并确定了化学性质。249 kg ha ^-1的磷矿石施用量磷的增加沿土壤剖面将土壤磷含量降低到7.5厘米。经过21年的熟化，中和前沿达到了大于10厘米的深度，再酸化作用不明显。在这些条件下，可交换的Ca，Mg和Al的含量以及pH值均大于，而Al的饱和度低于无石灰石时。然而，施肥和石灰石改良剂的效果受到时间的限制，并且在最后一次施肥后超过四年后，牧场干物质的生产没有反应。