Growth, Yield and Chemical Constituents of Corn (Zea Maize L.) As Affected by Nitrogen and Phosphors Fertilization under Different Irrigation Intervals

The present investigation was performed during two s uccessive seasons at the experimental station of NRC, Shalakan, Kalubia Governorate. The study aimed to evaluate the yield characters of maize plant CV. Single cross 1 0 (S. C.10) as well as the grain c hemical constituents in r espect to di fferent rates 25 25 25 of NP (40 kg N+15 kg P O / fed., 80 kg N+ 2 5 kg P O / fed. and 12 0 kg N+ 3 5 kg P O / fed.) at varying i rrigation i ntervals (10, 14 and 18 days). T he i mportant results could be summarized in t he following: Growth and yield of corn plants: The hi ghest values of plant height, ear characters (length, diameter and weight) as well as ears and grains yield of corn pl ants per f eddan i n bo th s easons were obtained under irrigation interval of 10 days followed by 14 and 18 days. Increasing rates of N P 25 fertilization up to 120 kg N+ 35 kg P O / fed. significantly increased all the studied parameters of growth and yield of maize plants, i. e. plant height, ear characters (length, diameter and weight) as well as ears and g rains yield/fed. as compared with the other N P f ertilizer levels. Except ear weight, all the previous parameters were significantly affected by the interaction between irrigation intervals and N P levels in both seasons. The highest values were attained under irrigation interval 10 days and using the N P level of 120 25 kg N + 35 kg P O / fed. while t he l owest values were obtained under i rrigation interval 18 days and unfertilized treatment. Grains ch emical constituents: Irrigation t reatment of 10 days interval gave the highest significant increase of all the chem ical constituents of corn gr ains, i.e. to tal P mg/g, total N mg/g, crude protein %, carbohydrate %, T.S. S. %, starch % and oil % followed by irrigation intervals of 14 and 18 days in descending order. All the used N P levels significantly increased the studied parameters of corn 25 plants as compared with control. The highest values were obtained by using 120 kg N+ 35 kg P O / fed. 2 5 25 followed by 80 kg N+ 25 kg P O / f ed. and 40 kg N+15 kg P O / fed. However, there were non 2 5 25 significant differences between the treatment 80 kg N+ 25 kg P O / fed. and 120 kg N+ 35 kg P O / fed. These results are true for al l the st udied parameters. Except total N mg/g and crude protein% the interaction between irrigation intervals and N P l evels significantly affected the chemical constituent of corn grains under study. The highest values of chemical constituent were obtained under irrigation interval 25 of 10 days and using t he hi ghest level of N P (120 kg N+ 35 kg P O / fed.), while t he l owest ones were obtained by irrig ation interval o f 1 8 days and unfertilized treatment (c ontrol). Generally, the growth, yield and chemical constituents of co rn p lants we re d ecreased by pro longing the irrigation int ervals to 18 days. The o btained data co nfirmed the i mportant role o f N P fertilization and irrigation f requency for gr owth, productivity and improve the chemical co nstituents o f m aize plant.