بررسي تاثير تنش كمبود آب، مقادير مختلف و شيوه توزيع نيتروژن بر عملكرد دانه و بازده نيتروژن ذرت دانه اي

The Impact of Varying Watering Regimes, Nitrogen Fertilization and Mode of Application on Grain Yield and Nitrogen Intake Efficiency in Corn

In order to study the impact of varying watering regimes, nitrogen fertilization along with its application on grain yield and nitrogen efficiency in com a research study was conducted in summer of 2004. The research was made as based on three split-plot field experiments, RCBD design. Irrigation treatments implemented were as follows: optimum irrigation, moderate and severe stress (irrigation after depletion of 50, 75 and 100% of available water, respectively). In each experiment three nitrogen levels consisting of 140 , 180 and 220 kg Nhaʹ1 were applied in main plots. Subplots were compristed of split mode of application of nitrogen (Sl= %50 at planting + 50% at V6 stage , S2= 25% at planting stage + 75% at V6 stage , S3 = %25 at planting + 50% at V6 stage + 25% at V12 stage). There were three replications for each experiment. Results showed that grain and biological yield, seed number per ear, and 1000 kernel weight were reduced significantly in response to increase in drought severity. The effect of nitrogen on grain and biological yield as well as on yield components (except number of row per ear) was significant. When available water decreased, positive effect of nitrogen application on grain and biological yield decreased significantly. In comparison with SI treatment, S3 increased grain yield as well as number of grains per ear, significantly. Crop efficiency nitrogen, use and uptake efficiency were significantly reduced in response to increase in drought severity and quantity of nitrogen applied. These traits in S3 treatment were more pronounced than in S1.