The effects of superficial lime application on chemical soil attributes under no-tillage systems and its influence on root growth and mineral nutrition in maize crops have not been thoroughly investigated yet. To evaluate these effects on maize and its reflexes on grain yield performance, a field trial was carried out on a dystrophic clayey Rhodic Hapludox, previously managed under no-tillage for six years, at Tibagi, State of Paraná, Brazil. The experimental design was a randomized complete block with four replications, using 44.8 m² plots. The treatments consisted of four liming rates (0, 1, 2 and 3 t.ha-1, pure CaCO3 equivalents) which represented 1/3, 2/3 and the total amount calculated for the soil to reach a base saturation of 70%, in the 0-20 cm layer. Dolomitic limestone (27% of CaO, 20% of MgO and 85% of ECCE) was broadcast-applied to the soil surface without incorporation. After 22 months, lime application increased soil pH in CaCl2 0.01 mol.L-1, exchangeable Ca and Mg, and base saturation, and reduced H + Al and exchangeable Al at the superficial layer (0-10 cm). It also increased exchangeable Ca and decreased exchangeable Al at the subsoil (20-40 cm). Liming did not significantly affect length and relative distribution of corn root at the 40 cm depth, reduced average root radius and increased plant uptake of P, Ca, Mg, and S, with no significant effects on grain yields. Surface lime application did not affect Cu, Fe, Mn and Zn concentrations in the soil and leaves or plant uptake of these micronutrients.
Zea mays L.; soil acidity; dolomitic limestone; root system; mineral nutrition
