CHANGES IN THE DRY-MATTER AND MACRONUTRIE NT CONTENTS OF MILLET (PANICUM-MILIACEUM L) DURING THE VEGETATION PERIOD

In a long-term fertilisation experiment on a calcareous, weakly humous sandy soil, examinations were made on changes in the dry matter accum ulation and N, P, K, Ca, Mg and S concentrations in millet (Panicum mi liaceum L.) during the vegetation period. Plant samples consisting of the complete aboveground part were taken on six occasions in major dev elopment phases from 4 linear metres (0.98 m(2)) per plot. The chemica l analyses were carried out using the ICP technique. Nitrogen was dete rmined by the Kjeldahl method. The conclusions can be summarised as fo llows: Dry matter formation exhibited a slow initial rate up to headin g, followed by an intensive phase up to flowering, and after a decline , again until full maturity. The grain: straw ratio was 1:2. In the NP and NPK treatments fertilisation significantly increased production, with the exception of the grain yield, compared to the control, indica ting the high demand of millet for N and P. The P, K and Mg concentrat ions declined continuously throughout the vegetation period, while tho se of N, Ca and S decreased to different extents at intervals, dependi ng on the soil moisture content. The concentrations of N and P were hi gher in the grain, and those of K, Ca, Mg and S in the straw. NPK fert ilisation led to a significant increase in N, P and K contents compare d to the unfertilised control, while in NP combinations there was also a significant rise in Ca, Mg and S contents. If the yields are taken into account, nutrient concentrations in vegetative stages can be used to estimate plant nutrient supplies and for the elaboration of limit values for Hungary.