The effect of calcium and magnesium rate in the correction of soil acidity and the effect of potassium on the production of dry matter of corn were assessed under greenhouse conditions. Corn seedlings were grown in plastic pots of soil Oxisol (Yellow Latosol dystrophic) in a randomised blocks and factorial design (4 χ 3) with four replications. Four calcium and magnesium rates (100/0; 75/25; 50/50 and 25/75) and three potassium levels (0; 100 and 200 mg dm-1 of soil) as potassium chloride were tested. Pure reagents as corrective (calcium and magnesium carbonate) were incorporated into the soil 21 days before planting and micronutrients applied as solution. Cobs were harvested 45 days after planting. Production of dry matter as well as potassium, calcium and magnesium contents were determined. Maximal production was recorded when the following conditions were reached: pH 6.3, 27.5 mmolc dm3 content, 18.0 mmolc dm3 content, Ca + Mg/K rate equal to 19.8 and Ca/Mg rate in the corrective equal to 1.1/1. The Ca/Mg rate was the main factor changing the production while crescent levels of potassium caused significantly increases in production, apart of liming and Ca/Mg rate. Crescent levels of potassium decreased in magnesium accumulation in the foliage of corn plants.
Zea mays; liming; soil acidity; macronutrients