Effect of Foliar-Applied Humic Acid to Dry Weight and Mineral Nutrient Uptake of Maize under Calcareous Soil Conditions

Greenhouse research was conducted to determine the effects of foliar application of humic acid on dry matter and some nutrient element uptake of maize grown under calcareous soil conditions. Agricultural lime was used to obtain five calcium carbonate (CaCO3) doses (0, 5, 10 20, and 40%) and three foliar application doses of humic acid (0, 0.1, and 0.2%) sprayed at 20 and 35 days after emergence. Although the dry weight and mineral element uptake of maize were affected negatively, especially at 20 and 40% of lime levels, foliar application of humic acid had a statistically significant positive effect on dry weight and copper (Cu), zinc (Zn), and manganese (Mn) uptakes (P 0.01) of maize plants. The greatest dry weight and Cu and sodium (Na) uptakes were obtained from the 0.01% humic acid treatment. The interaction of lime and humic acid was also statistically significant on dry weight, nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), Cu, Zn, and Mn uptake (P 0.01).