IRRIGATION AND NITROGEN FERTILIZATION INFLUENCES ON PROPERTIES OF SOYBEAN (GLYCINE MAX (L.) MERR.) VARIETIES

Field trials were set during a two year period under field conditions in Osijek. The aim was to confirm an influence of irrigation rate, nitrogen (N) fertilization and soybean varieties on seed yield and some yield components. The irrigation treatments were: control (A1); soil moisture content from 60% to 100% retention water capacity (RWC, A2) and soil moisture content from 80% to 100% RWC (A3). Rate of N was sub sub-factor: 0 (B1); 100 (B2) and 200 kg N ha-1 (B3), were applied. Una (C1) and Anica (C2) soybean varieties were a sub-sub factor (C). Mean soybean seed yields were 3082 kg ha-1 and 3538 kg ha-1 in 2006 and 2007, respectively. Irrigation resulted high statistically influence in soybean seed yield in both investigated years. Variety Una yielded (3179 kg ha-1) statistically very higher than Anica in 2006. Irrigation had significant effect in pod number plant-1 only in year 2007. Interactions AB and AC were significant in pod number plant-1, in one year, while BC interaction was in both years. Thousand seed weight (g) resulted in significant effect in irrigation treatment in both years, N fertilization effect in year 2007, while variety Una had highly significant higher value than variety Anica, in both years. Irrigation, N fertilization and variety had statistical very significant influence on seed weight plant-1 in one year, only. Seed weight plant-1 interaction effects AB, BC and ABC were very significant in one year, while BC interaction was in both years. Irrigation and variety had significant influence on seed number plant-1 in both years, while interactions AB, AC, BC and ABC showed significant effect in both years or very significant once