Effect of Nitrogen Source and Rates on Grain Yield, Morphological and Physiological Traits of some Maize Hybrids

Abstract

A field experiment was carried out in old newly reclaimed calcareous soils at Nubaria Agricultural Research Station, during 2015 and 2016 summer seasons. The aim of the investigation was to study the effect of nitrogen fertilizer sources (solid and gaseous) under different nitrogen rates (80, 100, 120 and 140 kg N fed-1) on yield, yield components, NPK concentrations and N use efficiency for some maize hybrids (SC 131, SC 168 and SC 176). Experimental design was strip-split plot design with four replications where nitrogen sources distribute in the vertical- plots while, nitrogen rates assigned to the horizontal- plots within N sources. Hybrids were randomly distributed in the sub - plots. Injection ammonia gas gave the lower significant averages value of number days from planting to 50% tasseling (DTT) and number of days from planting to 50% silking (DTS), but increased significantly in plant height (PHT), leaf area index (LAI), chlorophyll content (CHL), No. of ears per plot (EAR), grain yield (GY) and ear length (EL) in the two successive seasons as compared to those obtained with ammonium nitrate (AN) form. Results revealed that the application of AA was associated with significantly higher in kernel per row (KPR) and weight of 100-grains (KWT) than AN. No significant difference between the nitrogen sources was found in ear diameter (CD) in both seasons. Increasing N rates from 80 to 140 kg fed-1 caused a significant increase in DTT, DTS and EAR traits in 2016 only. However, increasing N rate significantly effect on PHT, LAI, CHL, GY, EL, KPR and KWT traits. Significant differences were found among maize single crosses for all tested growth characters and grain yield. Single cross 176 was the earliest hybrid while SC 168 was the latest concerning DTT and DTS in both seasons. Single cross 131 gave the highest value in GY, while SC 176 was the lowest value. Anhydrous ammonia (AA) had higher GY productive under all NR than AN with linear positive significant increase during the growing season of 2015. The highest grain yield was 36.9 ard fed-1 under 140 kg N fed-1 of AA while the lowest value was 24.0 ard fed-1 for AN at 80 kg N fed-1. Single cross 131 had the highest significant value in grain yield under AA, while SC 176 was the lowest value under AN fertilizer. Concentration of grain nitrogen (Nconc), phosphorus (Pconc), potassium (Kconc), their uptake (NPKuptake) and nitrogen use efficiency (NUE) were affected positively by the sources of N fertilizers applied in the two successive seasons. Ammonia gas (AA) enhanced all nutritional parameters comparing with AN. Three way interactions of the tested NS, NR and maize HB agreed with all previous results of main. In general SC 131 followed by SC 168 respond efficiently more than SC 176 to AA comparing with AN under all four N rates up to 140 kg N fed-1. Regression coefficient between grain yield  and the nineteen variables showed that there was a highly significant relation between grain yield and ten of the independent variables including (N uptake, N concentration, K uptake, K concentration, ear length, NUE, chlorophyll content, ear, no. of days to sillking, leaf area index). It was included that injection of AA to maize crop remarkably positively affect maize growth and N, P and K, compared with AN in calcareous soils.