Soil, being an important constituent of crop production, serves as a major source of plant nutrients availability as well as metabolic processes which are indispensible for plant growth, development and survival. The integration of humic acid and inorganic fertilizers may help to fight the deficiency of essential nutrients and improve the soil fertility for better crop yield. Bearing in mind the above objectives, the current study was carried out at the Agricultural Research Station, Swabi for two consecutive years of 2014 and 2015. The experiment was carried out in randomized complete block (RCB) design using split-split plot arrangement and three replications. Four maize genotypes (3025, 55w65, Jalal and Iqbal), four N levels (0, 120, 180 and 240 kg N ha-1) and four treatments of humic acid (0, 0.6, 1.2 and 1.6 kg HA ha-1) were included in it. Regarding maize genotypes, late emergence, maximum days to 50% tasseling, 50% silking, anthesis to silking interval (ASI), days to physiological maturity, seed fill duration (SFD), leaves plant-1, leaf dry weight plant-1 at silking, leaf area plant-1 at silking, leaf area index (LAI) at silking, absolute growth rate (AGR) and crop growth rate (CGR) at silking, plant biomass, plant height, yield and yield components, harvest index (HI), agronomic-nitrogen use efficiency (NUE-AE), partial factor productivity-nitrogen use efficiency (NUE-PFP) and net income (NI) were recorded for hybrid 55w65, while higher AGR as well as CGR at maturity and productive plants m-2 were calculated for hybrid 3025. However, maximum specific leaf area (SLA) plant-1, leaf area ratio (LAR) plant-1, net assimilation rate (NAR) (30-75 DAS), soil attributes (organic matter, P and N) at maize harvest and grain protein were observed for Iqbal variety. As far as humic acid (HA) treatments are concerned, maximum days to physiological maturity, SFD, leaves plant-1, leaf dry weight plant-1 at silking, leaf area plant-1, LAI, AGR, CGR at silking, plant biomass, plant height, AGR, CGR at maturity, productive plants m-2, yield and yield components were recorded at 1.8 kg HA ha-1. Furthermore, humic acid at 1.8 kg ha-1 provided higher grain yield, biological yield, harvest index, NUE-AE, NUE-PFP, NAR (30-75 DAS), soil attributes at maize harvest, grain protein and net income, while it resulted in lower SLA and LAR plant-1 at silking. Similarly, 1.8 kg HA ha-1 had earlier 50% tasseling and 50% silking, whereas higher SLA and LAR plant-1 were recorded for control plots of humic xv acid (0 kg HA ha-1). While considering the impact of nitrogen levels, delayed physiological maturity, SFD, higher number of leaves plant-1, leaf dry weight plant-1, leaf area plant-1, LAI, AGR, CGR at silking, plant biomass, plant height, AGR, CGR at maturity, productive plants m-2, yield and yield components, harvest index, NAR (30-75 DAS), soil attributes at maize harvest, grain protein and net income were observed at 240 kg ha-1 N, while it resulted in lower SLA and LAR plant-1 at silking. Similarly, 240 kg ha-1 N application induced earliness in days to 50% tasseling, 50% silking and shortened the ASI. Likewise, higher SLA and LAR plant-1 at silking were calculated at 0 kg ha-1 N. Moreover, higher NUE-AE was achieved at 180 kg ha-1 N while NUE-PFP was higher under 120 kg N ha-1. The integration of humic acid with nitrogen increased the number of days taken by the maize genotypes to attain their physiological maturity, SFD, the number of leaves plant-1, leaf dry weight plant-1, leaf area plant-1, leaf area index, AGR, CGR at silking, plant biomass, plant height, AGR, CGR at maturity, productive plants m-2, yield and yield components, harvest index, NAR (30-75 DAS), soil attributes at maize harvest, grain protein and net income. Moreover, the number of days to emergence, 50% tasseling, 50% silking and ASI were also reduced when the inorganic fertilizer of N was supplemented by humic acid in maize genotypes, with subsequent improvement in their NUE-AE, NUE-PFP. However, the SLA and LAR of maize genotypes exhibited a downward trend with the application of humic acid + N. Thus it is finally concluded that 240 kg N ha-1 + 1.8 kg HA ha-1 along with hybrid maize 55w65 may be used for obtaining higher grain yield and improving soil organic matter status under the agro-climatic conditions of Swabi region on sustainable basis.