Determination of the effects of different nitrogen levels applied by fertigation on yield and yield parameters of corn plant (Zea mays L. indentata)

In this study, it was aimed to determine the effect of nitrogen applied at different levels by fertigation method on yield and yield parameters of corn plant. The research was carried out in Şanlıurfa second crop conditions in 2018 and 2019 with 4 replications according to the randomized blocks experimental design. Ten nitrogen doses (0, 4, 8, 12, 16, 20, 24, 28, 32 and 36 kg N da-1) were used in the study. DKC 6664 corn variety was used as plant material in the experiment. Depending on the daily evaporation values and water needs of plant during the development stages of the plant, drip irrigation was applied at intervals of 4-6 days. Irrigation water is given as 1.25 of Class A Pan evaporation. Nitrogen doses were applied with drip irrigation by dividing throughout the vegetation period. The difference between the nitrogen doses in terms of the investigated properties was found to be statistically significant (P≤0.01). According to the average results of two years; an increase was observed in parallel with increasing nitrogen doses at the some properties such as tassel flowering period, plant height, number of leaves per plant, stem diameter, ear length, ear diameter, number of kernels per ear, grain weight per ear, thousand kernel weight, harvest index, leaf area per plant, dry matter yield, grain yield and biomass yield. The highest grain yield (1594 kg N da-1) and biomass yield value (6266 kg da-1) were obtained from 28 kg N da-1 nitrogen dose. While nitrogen use efficiency was higher at low nitrogen doses, nitrogen use efficiency decreased as nitrogen doses increased. According to the results of plant analysis; parallel to increasing nitrogen doses, Mg, Na, Mn, protein and starch values increased, Cu and B values decreased. In grain analysis, as the nitrogen dose increased, protein and fat ratios augmented. In silage analysis, Ca, Cu and protein ratios increased with the increase of nitrogen doses, while NDF and crude cellulose ratios decreased. Considering the results of the regression and economic analysis, it was determined that the highest grain yield and biomass yield of the corn plant was obtained from the 28 kg N da-1 nitrogen dose applied by dividing with drip irrigation.