Abstract
Corn was grown in a sandy loam soil in 8-kg pots. A basal dose of NPK (150, 120, and 100 kg/ha) fertilizers was mixed with the soil before potting and the treatment was repeated when the plants were 30 days old. Five different chelate fertilizers were applied 7 days after germination at three rates. Com plants were harvested 50 days after sowing, dried, weighed, and assayed for their aluminum, cadmium, calcium, cobalt, chromium, copper, iron, potassium, magnesium, molybdenum, lead, nickel, strontium, titanium, tungsten, vanadium, phosphorus and zinc content. The maximum dry matter yield was found in F3 treated plants, followed in descending order by F1, F2, F4, F5, and Cont (control). Application of fertilizer F3 completely eliminated iron-deficiency symptoms. Fertilizers (Fl and F2) prepared from fish extract were better in improving dry matter yield than the lignosulfates and inorganic chemicals, but inferior to fertilizer F3. Concentrations of iron, phosphorus, and calcium followed the intensity of chloritic symptoms, i.e., the highest concentrations in the control and the lowest in fertilizer F3. In general, barium, chromium, cobalt, lead, nickel, molybdenum, vanadium, and zinc were higher in com plants receiving fertilizers F1 and F2. The results of regression analyses indicated that the interactions between the above elements can be grouped in to three categories according to their associations with each other; (a) elements iron, calcium, strontium, and phosphorus were strongly (P<0.001) intercorrelated, (b) elements chromium, cobalt, nickel, lead, titanium, molybdenum, vanadium, and zinc were very significantly (P<0.001) associated, and (c) all the remaining elements had no special associations.