GROWTH AND YIELD RESPONSE OF TWO CORN VARIETIES (ZEA MAYS L.) FOR TREATMENT SPLIT APPLICATION OF DIAMMONIUM PHOSPHATE (DAP) FERTILIZER

The current study aims at identifying the performance of two cultivars of maize under time application levels of adding ammonium diphosphate fertilizer during the two seasons of planting and its effect on the characteristics of the vegetative growth, the yield and the qualitative components of Zea mays L. The study was conducted during summer 2021 and autumn seasons in one site in Talafar district, which is about 60 kilometers from Nineveh governorate center. The field experiment involves two factors; the first is the cultivars: (1) Masarrah, (2) Rabea' and the second factor is the addition of nitrogen and phosphate fertilizers with certain levels and time application of Di Ammonium Phosphate fertilizer (DAP) addition and this factor included seven levels. The results showed the superiority of the cultivars Rabea' in the number of planting days to have 75% male blooming compared to the cultivars (Masarrah) in the spring season. On the other hand, this characteristic had no superiority in the autumn season. As for the rest of the vegetative growth characteristics, there were no significant differences between the two cultivars (Masarrah and Rabea'). The characteristics of the yield, its components and the qualitative components had no significant superiority in terms of the treatment of the cultivars. The seventh treatment of adding the fertilizer was superior over the rest of the fertilization treatments as it had the highest significant superiority in terms of the characteristics of the yield, its components and the qualitative components (chlorophyll content in the leaves under the cobs, biological yield, number of cobs, number of grains, weight of 500 grains, grain yield and the oil yield). There was no significant interaction between the treatment of the cultivars and the treatment of adding the fertilizer between summer and autumn seasons.