ABSTRACT

Segmental liming involves the incorporation of lime into the subsoil in narrow strips, typically associated with deep ripping. This study aimed to evaluate the vertical and horizontal distribution of soil acidity and nutrient availability in a Ferralsol under no-tillage five months after segmental liming. The equipment used for lime application featured a chisel of seven rods with a spacing of 70 cm, and a working depth of 40 cm. The lime rate used was 1.0 Mg ha^-1 of limestone with high effective neutralizing value (ENV = 170%). Soil samples were taken at eight layers (0-5, 5-10, 10-15, 15-20, 20-25, 25-30, 30-35, and 35-40 cm), in the passage line of the equipment and at 10, 20, and 30 cm to the side between rods. The available soil phosphors (P) and potassium (K) did not exhibit any horizontal and vertical changes as a result of segmental liming. Conversely, within the 10-25 cm depth along the rod application line, the soil pH increased from 5.3 to 5.9. Additionally, the exchangeable Ca increased from 60 to 78 mmol_c dm^-3 and the exchangeable Mg increased from 21 to 32 mmol_c dm^-3. The base saturation also increased from 56 to 73%, and the Al saturation decreased from 11 to 2%, when compared to samples collected at 10, 20, and 30 cm from the segmental liming application line. Therefore, the correction of soil acidity through segmental liming was limited to the chisel line, accounting for the correction of soil acidity in only 14.2% of the cultivation area.

Key words
Subsurface acidity; Limestone incorporation; No-tillage