Applying lime on the soil surface in soils managed under no-tillage has caused an excess of basic cations in the most superficial layers of the soil profile. On the other hand, subsoil acidity is considered a constraint to the development of deep plant roots. The objective of this study was to evaluate Ca2+, Mg2+, NO3- and SO4(2-) leaching in the soil profile as affected by liming and top dressing nitrogen fertilization in cotton, grown with straw cover on the soil surface. Cotton plants (Gossypium hirsutum) were grown for 60 days in PVC columns filled with a Distroferric Red Latosol (sand loam Rhodic Oxisol) with liming applied over the straw on the soil surface, incorporated liming 0-20 cm deep, or without liming. Nitrogen was applied at rates of 0, 50, 100 and 150 kg ha-1 as ammonium sulfate. The PVC columns were set up in layers of 0-5, 5-10, 10-20, 20-30 and 30-50 cm, totaling 15.71 dm³. The ammonium sulfate application caused intense leaching of SO4(2-) in the soil, irrespective of the lime application method. Liming increased the concentration of NO3- in the 0-20 cm soil layer, whereas the correction of the soil acidity did not affect the NO3- concentration in the 30-50 cm soil layer. The influence of ammonium sulfate on Ca2+ leaching below 20 cm was only observed in the soil with incorporated lime. Nitrogen application resulted in extensive Mg2+ leaching from the soil, regardless of the lime application method. In the soil layer below 30 cm, SO4(2-) presented a higher correlation than NO3- in the formation of ionic pairs with Ca2+ and Mg2+.
calcium; magnesium; potassium; nitrate; no-tillage
