Evaluation of the Residual Effects of New Methodologies of Correction Surface and Subsurface Acidity on Soil Chemical Attributes in Agropastoral System

Surface and subsurface acidity (pH < 4.4) limits nutrient availability and root exploration, whereas a pH range of 5.4–6.4 ensures the availability of most nutrients that are essential for crop productivity. To ameliorate acidity in the surface and subsurface layers and improve soil chemical fertility, different application methodologies (surface, incorporation by soil tillage, or subsurface) for calcium (Ca) compounds (limestone (LS), phosphogypsum (PG), and hydrated lime (HL)) were evaluated in an agropastoral system in an Arenic Hapludalf in Brazil during the 2017–2020 seasons. Two seasons after the last application of Ca compounds, the soil was sampled and analyzed to evaluate the long-term ability of these different application methodologies. In the 0.0–0.2 m layer, the correction of surface acidity via increased pH and base saturation (BS) and reduced total acidity was maintained, but the improvement in acidity in the 0.4–0.8 m layer previously observed after the incorporation of LS and subsurface application of HL in the 2017-2018 season was not. Moreover, the improvements in Ca2+ content and Ca2+/cation exchange capacity (CEC) after applying LS plus PG and Mg2+ content and Mg2+/CEC after applying HL plus PG were preserved in the surface layer. The positive effects of these amendments on sulfate-S (S-SO42-) content throughout the soil profile (0.0–0.8 m) were not. Finally, Ca compound application had residual positive effects on P content in the 0.1–0.8 m layer and organic matter (OM) content in the 0.2–0.8 m layer.