The experiment focused on widely used maize hybrid variety, Gorilla, to dissect the productivity responding to nitrogen management. The conducted research was accomplished in randomized complete block design (RCBD) with three replications at the research farm of University of Swabi, Khyber Pakhtunkhwa, Pakistan, in summer of 2017/18. Nitrogen (N) factor was applied to each plot with four different treatments, i.e. urea (100%, CK), urea (50%) + farm yard manure (FYM) (50%), urea (50%) + poultry manure (PM), urea (50%) + compost (50%), respectively.

The seeds were sown in ridges with distance of 75 cm between rows and 20 cm between plants with 22 shoots each row. Phosphorous was applied as a source of DAP (Diammonium Phosphate) as 90 kg∙ha⁻¹ as a basal dose. Before sowing, maize hybrid seeds were treated with disinfectant Confidor WG 70 (Water Dispersible Granules) to avoid soil borne pest and disease. The urea was used as fertilizer for nitrogen source. The pot doses of nitrogen were applied 1/3 in seedling stage, 2/3 at elongating stage. All other agronomic methods were used common and similar for all treatments.

Data for plant height (cm) was collected two weeks after pollination. While datasets for ear length (cm), ear weight (g), kernels per year, total kernel weight (kg per ha), kernel yield (kg∙ha⁻¹), and biomass yield (kg∙ha⁻¹) were collected after naturally drying of all harvested ears and stalks. Harvest index (HI) was calculated via kernel yield divided by biomass yield.

Datasets of eight traits were input into Microsoft-Excel (version 365), and the means were calculated. Multiple comparisons of the means for each trait at different N levels were carried out by the software Statistix 8.1.

Data concerning plant height are presented in Table 1. Significant difference was present in treatments as compared to control (Value). Among the treatments there was a significant difference found i.e. plants treated with urea + PM showed higher plant height 231.46 cm followed by Urea + compost, urea + FYM i.e. 225.75 cm and 211.06 cm, respectively. For maize hybrid, application of N

*Capital letters refer to the significant level of 0.05, and those means followed by the same capital letter refer to non-significance (P > 0.05), while those followed by different to significant difference (P < 0.05). The same as the following tables.

with some other manures, i.e. PM, compost, even FYM, tends to promote higher plant height rather than N alone (Table 1). Similar trends were also documented by the other reports [13] [14] [15] .

Significant differences were observed among the four treatments for both two ear-related traits, i.e. ear length and ear weight (Table 1). Higher ears length was recorded under both treatments of urea 12.10 cm and urea + FYM 12.17 cm, while shorter at both urea + PM (10.71 cm) and urea + compost 10.42 cm (Table1). Similar trends were also noted by previous studies [16] .

Differed from ear length, ear weight responded oppositely to fertilizer treatments (Table 1). Relatively higher ear weight was achieved at both treatments of urea + PM 165.19 g and urea + compost 163.02 g. These results indicated that the combined application of urea + PM and urea + compost tended to produce shorter but heaver ears in maize, in accordance with the reports of Ali et al. [11] .

Data regarding number of kernels ear⁻¹ are presented in Table 2. The maximum kernels ear⁻¹ were recorded in the plot where urea + PM (435) applied followed by the urea + compost (424) than urea + FYM (375) and urea alone (360) (Table 2). PM and compost combined with urea caused significant positive effects to increase the number of kernels for maize ears (Table 2). Our results are in line with [13] [17] .

Similar to the number of kernels ear⁻¹, the total kernel weight ear⁻¹ was highly recorded at urea + PM followed by the urea + compost, then urea + FYM and urea alone (Table 2). The highest value was 350.75 g, followed by 347.29 g, than 321.29 g and 308.71 g respectively. Similar trends were also documented by Ali and colleagues [11] .

Kernel yield data are showed in (Table 2). Kernel yield was significantly affected by nitrogen as compared to other treatment (P < 0.05). The kernel yield was recorded maximum in the treatment of Urea + Poultry. In general, application of manure increased grain yield as matched to the control. Among all the treatments the highest kernel yield was recorded under the treatment of Urea +

PM, followed by Urea + FYM, turned to Urea + Compost and lowest at control that is (2095.7 kg∙ha⁻¹), (2061.2 kg∙ha⁻¹), (1958.1 kg∙ha⁻¹) and (1873.1 kg∙ha⁻¹) respectively. The significant promotion of manures and compost to the performances of kernel weight per ear and kernel yield were also documented previously in maize production [13] [17] .

Data regarding biomass yield were shown in Table 3. High biomass yield was recorded in those plots of urea + FYM, followed by urea + compost, urea and then urea + PM. The highest value was 4015.3 kg∙ha⁻¹, followed by 3769.0 kg∙ha⁻¹, 3748.6 kg∙ha⁻¹ and 3709.5 kg∙ha⁻¹, respectively. However, except the treatment of urea + FYM, the other treatments including urea, urea + PM, and urea + compost produced similar biomass yield, with non-significant differences (Table 3). Similarly, a few researchers also documented the positive effects to HI by integrating application of inorganic and organic nitrogen to maize hybrids [11] [18] .

Harvest index (HI) data is present in Table 3. The maximum harvest index was recorded in the plot where urea + PM was applied then followed by urea + FMY, then urea + compost and turned to urea alone. The highest HI was noted at urea + PM, while minimum lower was observed in control (urea alone). The highest value is 37.31%, followed by 36.44%, 35.96% and 30.06%, respectively (Table 3). Our results are in line with [11] [18] .