Evaluation of yield, water use efficiency and Nitrogen efficiency in corn cultivation in Khuzestan province

Water and nitrogen are the main factors limiting the maximum yield Achievement. Application of nitrogen fertilizer has great impact to increasing agricultural production. On the other hand, the high use of these fertilizers is due to the low efficiency of these fertilizers. This research was conducted in response to the challenges of water scarcity and inappropriate management of nitrogen utilization. To quantitate the reaction of the plant and calculate the water and fertilizer efficiency, two irrigation levels, full irrigation (I1) and deficit irrigation equal 30% (I2) as the first factor and two nitrogen levels of 200 (N1) and 160 (N2) kg per hectare, it was considered as a second factor. Experiments were carried out as field treatments and in lysimeters as a factorial in a completely randomized block design with three replications. The cultivars used were maize hybrid 611 and 704 mediator SC, which were cultivated in two seasons of spring and autumn, respectively. Based on the results of this study, leaf area index with higher nitrogen application in the same moisture conditions is increased. Nitrogen increase, while that enough water is available to the plant, increases the weight of 1000 seeds, grain yield, biological yield and harvest index. Optimum use of water and nitrogen fertilizer increases grain yield and therefore increases water use efficiency. With increasing nitrogen content, nitrogen use efficiency decreases in corn cultivation. Under stress conditions, with increasing nitrogen consumption, fertilizer N-recovery efficiency is also reduced by decreasing the absorption of this element by the plant. The economic and biological efficiency of water use in autumn cultivation was more than spring cultivation. Low spring yield and high rainfall during autumn crop period were due to the efficiency and more productivity of water use in autumn cropping. In Khuzestan weather conditions, the use of early cultivars is recommended instead of the mediator for spring crop due to coincide the pollination time with intense heat.