EFFECT OF FERTILIZER ON THE CONCENTRATION OF MICRONUTRIENTS IN MILLETDURING THE VEGETATION PERIOD

In a long-term fertilisation experiment set up on calcareous sandy soi l, studies were made on changes in the concentrations of the elements Fe, Mn, Zn, Cu, B, Mo and Na in the whole aboveground parts of miller (Panicum miliaceum L.) during the vegetation period. Plant samples wer e taken from 0.98 square metres par plot in the six major developmenta l phases. The analyses were carried out using the ICP technique. The f ollowing conclusions can be drawn from the results: A decreasing trend could be observed during the vegetative phase up to flowering in the case of Fe, Mn, Cu and Na. The opposite was tone of Mo, where an incre ase was recorded, while very little change was found for Zn and B. In the generative phase the concentration of Fe, Mn, Zn and B increased, while that of Ma declined. At maturity there was an accumulation of Zn and Cu in the grain and high concentrations of Fe, Mn, B, Mo and Na i n the straw. The effect of NPK fertilisation was significant at differ ent times for different combinations. There was a significant increase in Fe in the grain from flowering to full maturity, in the N, NP and NPK treatments, and in Mn and Cu from heading onwards in the N and NP treatments and at harvest in all the fertiliser treatments. in the cas e of Zn there was a significant increase in the N treatment, but a sig nificant decrease in the NP and NPK treatments compared to the untreat ed control, due to P/Zn antagonism. NPK treatment led to a reduction i n the B concentration in the straw and to that of Mo in the green plan t and at harvesting. In the case of Na the increasing effect of potass ium could only be proved in the green plant after heading. Element con centrations in young plants can be used to determine limiting values f or supply levels in Hungary.