engleski

Response of the seed maize (Zea mays L.) to fertilization

In general, soil and climate conditions in the Pannonian region of Croatia are favorable for seed-maize production. However, growth retardation and chlorosis (the signs of either zinc or potassium deficiency at early growth stage of seed-maize) have been appeared. Cold and moist spring is mainly factor promoting these disorders, but a considerable role of inheritance concerning degree of susceptibility to stress conditions was found. In total 16 field trials were conducted during three growing seasons (1991, 1992 and 1993). Different treatments of fertilization (incorporation of the broadcast applied fertilizers by the tillage interventions immediately prior to sowing) were used as follows: a) zinc (13 kg Zn ha-1 in ZnSO4 form) ; b) emphasized phosphorus and potassium fertilization (170 kg of P2O5 and K2O ha-1 in the form of NPK 8:26:26 fertilizer). Standard fertilization was used as a control and it was additional fertilization to the treatments a and b. Influences of fertilization on grain yields of seed-maize were different. They depended on numerous factors including degree of weather favorability (factor: growing season), applied nutrient, as well as soil/plant characteristics (soil type and genetic properties of mother parent of seed-maize). Significant influences of fertilization were found in 8 trials. In general, zinc incorporation into soil something more affected maize yield in comparison with P and K fertilization. Drought period affected considerably on maize yields for the growing season of 1992 an on absence response to fertilization. Very high differences of grain yields of seed-corn were found among the control treatments of these field trials: from 2.02 t /ha to 6.13 t /ha. Our opinion is that they were influenced considerably more by degree of homozygotity of the mother parent than by soil characteristics. Regarding this, grain yields of pure inbred lines are considerably lower in comparison with those of modified inbred lines and especially single-crosses.

ertilization; seed-maize; zinc; potassium; phosphorus

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