EFFECT OF NPK FERTILIZATION ON THE INDIVIDUAL AMINO-ACID CONTENT OF WHEAT-GRAIN

The individual amino acid content of wheat seeds from long-term NPK fe rtilizer trials grown on heavy-calcareous and humus-rich meadow soil i n 1991 has been examined by a RP HPLC method, in order to determine th e effect of increasing NPK supply. Higher N doses increased the amount of ASP, GLU, SER, HIS, GLY, THR, ARG, ALA, TYR, VAL, PHE, ILE, LEU an d LYS by 6-24%. The highest values were obtained at 180 kg N/ha fertil izer level, except for ARG and HIS. Increased PK doses significantly d ecreased the quantity of ASP, GLU, SER, HIS, GLY, THR, ARG, ALA, TYR, CYS, VAL, PHE, ILE and LEU. When N and PK were applied together, the a mount of amino acids did not change to such an extent as in the case o f separate N or PK doses. The two wheat varieties studied showed signi ficant differences only in the amount of SER, CYS and PHE.