The impact of different levels of nitrogen fertilizer on maize hybrids performance under two different environments

A field experiment was conducted at Agriculture Research Farm, College of agriculture, University of Sargodha and National Agricultural Research Centre, Islamabad to compare maize hybrids (H) and nitrogen (N) rates, growth, yield and yield components, using a split plot design with three replications in 2017 and 2018. The main plots were supplemented with one of the following levels of N (kg ha-1: 100 (N1), 175 (N2), N3 (250), N4 (325), and N5 (400) using three different hybrids (H), H1 (P-3939), H2 (30-T-60), and H3 (30-Y-87) in the sub-plots. Data were analyzed using the MIXED procedures of SAS. The statistical models included the individual effects of N and H, the interactions between N and H, and the random effect of the year. Orthogonal polynomial contrasts were constructed to determine the optimum level of N. The yield and yield components were improved at 325 kg N ha-1 with significant effects on maximum plant height, number of grains per cob, number of grains per m2 and grain yield. The results revealed that yield, total number of grains m-2, number of grains per cob, 1000 grains weight, number of grain rows per cob, cob girth, and cob length were maximized (P < 0.001) at the N4 level without having an interaction with the H of maize crop. It was concluded that the selection of best H for each location at 325 kg N ha-1 can be used to enhance the efficiency of maize yield in autumn season at both locations under irrigated conditions.