EFFECT OF IRRIGATION INTERVAL, ORGANIC MANURING AND NITROGEN FERTILIZATION LEVEL ON YIELD AND YIELD ATTRIBUTES OF MAIZE

This investigation was carried out in an demonstrated field at Al-Ibrahimia District, Sharkia Governorate, during 2011 and 2012 seasons to find out the effect of irrigation interval (14 and 18 days), starting from 3^rd irrigation (48 and 52 days after planting) organic manuring (check, 20 m³/fad., farmyard manure “FYM” and 5 tons compost/ fad.) and three N levels (20, 60 and 120 kg N/fad.) on yield and its attributes of maize (single cross 129). The irrigation interval had no significant effects on maize grain yield and its yield attributes. However, the combined analysis detected significant differences in shelling percentage and harvest index where, irrigation interval every 14 days recorded higher averages compared with irrigation every 18 days. Addition of 20 m³/fad., of FYM, significantly increased grain, ear, stover and total yields/ fad., ear length, number of grains/ ear, 100-grain weight and grain weight/ ear according to the combined analysis. Increasing N level up to 120 kg / fad., gave significant increments in grain yield and yield attributes except shelling percentage which was decreased. Stover yield was responded only to 60 kg N/ fad. Increasing N levels had no significant effect on of number rows/ ear and grain protein content. The first order interactions between factors had significant effects on some yield attributes. The most interesting of these was detected with ear and grain yields/ fad., traits in the second season. Organic manuring was effective to avoid a significant decrease in ear and grain yields/ fad., which was observed in the un-manured plots when the irrigation interval was prolonged to 18 instead of 14 days. Such finding confirmed the benefits of organic manure in improving soil-water holding capacity which functionally reduces water requirements for plants.