Response of Yellow Maize Yield to Preceding Crop Effect and NP Fertilization Level

THIS STUDY was conducted in the Experimental Farm, Ghazala Village, Faculty of Agriculture, Zagazig University, El-Sharkia Governorate, Egypt, during two successive seasons (2014 and 2015). The study aimed to find out the effect of preceding crop (berseem and wheat), phosphorus "P" (0, 15.5 and 31 kg P2O5/ fad*) and nitrogen "N" (40, 80 and 120 kg N/ fad) levels on yellow maize yield and its attributes. The results clearly clarified the possibility of saving N additions when maize was preceded by berseem than when preceded by wheat. Though ear length and diameter and the grain set per ear as expressed in the number of rows per ear, number of grains per row, number of grains per ear and total yield/ fad were not significantly increased, however, grain filling as expressed in seed index and grain weight per ear were significantly increased due to growing maize after berseem and hence the grain and ears yields per fad, shelling percentage and harvest index were increased compared with growing maize after wheat. Regarding P levels effect, the first increment (15.5 P2O5/ fad) was quite enough for increasing grain yield per fad and almost all of its attributes, where the further increase in P level did not add any significant increase in this respect. Finally, the grain yield, ears yield and hence the total yield per fad responded to each N increment up to 120 kg N/ fad, but, the stover yield responded to only 80 kg N/ fad and hence the harvest index was the highest (41.30 %) at the lowest N level (40 kg N/ fad). The most frequent first order interaction between factors under study was that between the preceding crop and N levels which indicated the need of lower N level in order to maximize the grain yield per fad when maize was preceded by berseem compared with after wheat. The grain yield response to N level was diminishing where 50.8 kg N/ fad were needed to maximize the grain yield to 3.03 ton/ fad compared with 105.7 kg N/ fad needed to maximize the grain yield to only 2.89 ton/ fad when maize was preceded by berseem and wheat, respectively.