Nutrient Uptake of Maize Plants (Zea mays L.) in Relation to Zinc Deficiency.

A three year field experiment using zinc sulfate supplements was conducted in Moldova to study nutrient uptake of maize plants in years 13 through 15 of systematic application of mineral fertilizers (no-fertilizer control, P60, N60K60, N60P60K60, N90P60K60, N60P90K60, kg ha-1). Zinc treatments for three years were P60Zn10, N60P60K60Zn5, N90P60K60Zn5 and N60P90K60Zn10 on half of each long-term treatment. The objective of this study was to determine the macronutrient uptake of maize plants in relation to zinc deficiency and plant chlorosis. The soil at the experiment site was a calcareous chernozem, containing: humus 4.3%, total nitrogen 0.29%, CaCO3 1.7%, plant available phosphorus and potassium averaging 0.88 and 34.5 mg/100g respectively, extractable cations Ca2+ and Mg2+ 31 and 2.9 meq/100g respectively, with pHH2O value of 7.9 at the 0-20 cm soil depth. Long term phosphorus application increased available phosphorus, induced zinc deficiency and decreased nutrient uptakes by maize. Measured in maize at milk-dough stage maturity, the combined application of macro and microelements (N60P90K60 and N60P90K60Zn10) increased: the total nitrogen uptake in leaves by 159 mg plant-1 dry weight, in stem by 142, in husk by 171, in cob by 100, in grain 1094; total phosphorus uptake in leaves increased by 52, in stem by 68, in husk 78, in cob by 49, and in grain by 387; total potassium uptake in leaves increased by 73, in stem by 148, in husk by 175, in cob by 172, and in grain by 317. Maize yield was increased from 470 to 660 kg ha-1. The total nitrogen, phosphorus and potassium uptake in tassel increased slightly. The results can be helpful in developing maize nutrient management on carbonate chernozem soil in dryland cropping system.