Organic manure is considered a good source of all essential nutrients and organic matter. It has a number of benefits in comparison with inorganic fertilizers due to its organic nature. These benefits include improved soil structure, enhanced water holding capacity, more pore spaces for aeration for better growth of the plants. Field trials were conducted in randomized complete block design with three replications at Agronomy Research Farm, the University of Agriculture Peshawar during summer 2017 and 2018. The experiment was consisted of two factors i.e. organic nitrogen sources (poultry manure (PM), farmyard manure (FYM) and legume residue (LR) and their ratios i.e. 100:0:0, 0:100:0, 0:0:100, 50:50:0, 0:50:50 and 50:0:50 in the form of non-compost, compost and biochar. A control and inorganic nitrogen (N) fertilizer treatments were also included in the experiment. Results of the data exhibited that PM delayed tasseling, silking and maturity in comparison with FYM and LR. Likewise, PM increased plant height (220 cm), leaf area (343 cm²), leaf area index (2.94), grains ear^-1 (493), thousand grain weight (322 g), biological yield (15102 kg ha^-1), and grain yield (5370 kg ha^-1) as compared to FYM and LR. In similar way, FYM also increased plant height (219 cm) and harvest index (36.7%). Among organic N ratios, the 100:0:0 (non-compost:compost:biochar) delayed tasseling, silking and maturity. Likewise, the ratio of 0:50:50 (non-compost:compost:biochar) enhanced plant height (229 cm), number of leaves plant^-1 (13.3), leaf area (364 cm²), leaf area index (3.38), ears m^-2 (7.2), grains ear^-1(509), thousand grain weight (333 g), biological yield (15328 kg ha^-1), and grain yield (5607 kg ha^-1). It is concluded that application of PM and organic nitrogen ratio of 0:50: 50 (non-compost: compost: biochar) improved yield and yield traits of maize.

Keywords: Biochar, grain yield, maize crop, organic amendments