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The teosinte plant is one of the most important fodder crops that is affected by drought and nitrogen supply, and therefore the optimal supply of N- fertilization may be affected by the amount of irrigation water added to teosinte plants to obtain an economic crop. Two field experiments were done to study the effect of irrigation amount at three levels (100%, 80% and 120%) and nitrogen fertilizer levels (140, 210 and 280 kg N ha-1) on the yield productivity of teosinte and determined the optimal and economic optimal N rate as affected by irrigation amount levels, and water relations. The results showed that the highest values of the fresh and dry weight of cuts, as well as plant height and stem diameter, were obtained when applying the full irrigation rate with full irrigation and 280 kg N ha-1. The results also showed that a 20% decrease in the irrigation rate led to a deterioration in the values of those parameters. Although the results showed that the full irrigation amount more saved water at two seasons under various levels of nitrogen. Moreover, all water relationships gave the best mean values for actual evapotranspiration, water utilization and use efficiencies also, higher application efficiency values at full irrigation and 280 kg N-levels than the other treatments. Also, the results showed that the highest economic yield was obtained when using 120% of the recommended irrigation water, with the use of 496.75 kg N ha-1. Despite this, it is recommended to use the full irrigation rate with the use of 345.03 kg N ha-1, as it gave an economic yield less than that with use 120% of the recommended irrigation amount by 2.19% while providing nitrogen fertilization by 43.97%, thus preserving the environment Pollution by loss of nitrogen fertilization through agricultural drainage or volatilization.