The effects of superficial lime application on chemical soil characteristics in no-tillage systems and its influence on root growth and mineral nutrition in maize crops has not been thoroughly investigated yet. To evaluate these effects on maize (hybrid AG 9090) and its reflexes on the grain yield performance under no-tillage, a field trial was carried out on a dystrophic Red Latosol (Hapludox) in Ponta Grossa, State of Paraná, Brazil. A completely randomized block design with three replications was used in a split-plot experiment. In the main plots, four rates of dolomitic limestone were applied on the surface (0, 2, 4 and 6 t ha-1) in July 1993, and two rates of dolomitic limestone (0 and 3 t ha-1) reapplied on the surface of the subplots in June of 2000. After 92 months, liming had decreased the exchangeable Al and increased pH, exchangeable Ca and soil base saturation values, down to a depth of 0.60 m. Similar effects were observed nine months after lime reapplication down a depth of 0.20 m. Under higher soil acidity, lime reapplication upon the surface provided a faster reaction. Root growth and grain yields of corn, grown unaffected by water deficits and under high concentrations of organic matter, were not limited by concentrations of 10 mmol c dm-3 of exchangeable Al in the soil. The relative root distribution, however, was improved by surface liming in compacted soil. Superficial dolomitic limestone application under no-tillage system caused an decrease of the K concentration in the corn leaves, without affecting the grain yield.
Zea mays L.; dolomitic limestone; calcium; aluminum; mineral nutrition; root system