Effect of mineral nitrogen fertilization on growth characteristics of lucerne under induced water deficiency stress

Utility of lucerne crop fertilization with nitrogen fertilizer has been discussed in literature with controversy. in this study experiment was conducted to determine the effect of mineral nitrogen at the doses of 40,80,120 and 160 mg n/kg on some characteristics of lucerne under induced water deficiency stress at the stage of budding in a pot trial. it was found that mineral nitrogen at the doses of 120 and 160 mg n/kg soil increased the productivity of dry top mass by 17 and 23% in conditions of optimum moisture,and by 9% in conditions of water deficiency stress at the dose of 80 mg n/kg soil. application of mineral nitrogen at the dose of 120 and 160 mg n/kg soil increased the quantity of dry root mass by 43 and 38% for the conditions of optimum moisture,and by 54-56% for conditions of water deficiency stress. mineral nitrogen fertilizing at the dose of 40 mg n/kg soil had the lowest suppressive effect on the nodulation (11%). the dose of 160 mg n/kg soil was found to be toxic to nodulation. the dose of 80 mg n/kg soil,at which the crop had the lowest sensitivity to water deficiency stress,was optimal for lucerne development.