A field experiment entitled “Effect of biochar and humic acid on fertilizer use and yield of maize (Zea mays L.) in Alfisols of Southern Telangana region of Andhra Pradesh” was conducted during kharif, 2013-14 at College Farm, College of Agriculture, Rajendranagar, Hyderabad, Andhra Pradesh. The soil of the experimental site was sandy loam with a pH of 7.72, electrical conductivity 0.217 dS m-1; low in organic carbon (0.49%) and available N (138.6 kg ha-1), high in phosphorus (31.28 kg ha-1) and potassium (629 kg ha-1) and sufficient in available sulphur (28 ppm). The experiment was laid out in Randomized Block Design with three factors; factor-I (100% and 75% NPK), factor- II (Biochar @ 0, 5 and 7.5 t ha-1) and factor-III (Humic acid @ 0 and 30 kg ha-1) with three replications taking maize (DHM-117) as test crop. The observations on dry matter production were taken at 30, 60 and harvest. Soil samples at initial, 30 and 60 DAS, at harvest were analysed for pH, EC, CEC, OC, available N, P, K, S and enzyme activity (dehydrogenase, acid and alkaline phosphatase). Bulk density and water holding capacity for initial soil was estimated. Characterization of humic acid and biochar was done for various properties. Economics including gross, net return and B: C ratio was calculated. Biochar was moderately alkaline in nature having CEC of 49 c mol (p+) kg-1. E4/E6 ratio and CEC of humic acid was 4.86 and 86 c mol (p+) kg-1 respectively. The fertiliser, biochar and humic acid levels and their interactions was found to be significant in increasing the dry matter production. The highest dry matter production of 452 and 1672 kg ha-1 and 91.43 q ha-1 was observed in the treatment receiving 100 % NPK along with biochar @ 7.5 t ha-1 and humic acid 30 kg ha-1 at 30, 60 DAS and harvest stages respectively. Application of recommended dose of NPK, biochar at 7.5 t ha-1and humic acid at 30 kg ha-1 were significant in increasing seed yield. Though in the absence of biochar, 75% NPK put forth significantly lower yield than 100% NPK, integration with biochar at the highest level of 7.5 t ha-1 and humic acid at 30 kg ha-1, the yields from the two levels of fertilisers were at a par. Individual application of biochar and 100% NPK significantly increase the N content of maize stover. Among Interactions, N content significantly increase with treatment receiving biochar @ 5 t ha-1 along with humic acid. While at 60 DAS, N content was non significant for maize stover, whereas at harvest and for seed higher N content was observed in 100% NPK along with biochar @ 7.5 t ha-1 and humic acid 30 kg ha-1 followed by treatment receiving 75% NPK along with biochar @ 5 t ha-1 and humic acid 30 kg ha-1. Interaction among factors were non significant in respect of P content at 30 DAS, whereas at 60 DAS and for seed, higher P content was observed with 100% NPK along with biochar @ 7.5 t ha-1 and humic acid 30 kg ha-1 but at harvest highest P content was observed with 75% NPK along with biochar @ 7.5 t ha-1 and humic acid 30 kg ha-1. The K content at 30 DAS was not influenced by the factors either alone or in combination. Highest K content at 60 DAS and in seed was observed with 100% NPK along with biochar @ 5 t ha-1 and humic acid 30 kg ha-1, at harvest, K content of stover was higher with 100% NPK with humic acid 30 kg ha-1. At 30 and 60 DAS, higher S content was realised with 75% NPK along with humic acid. Whereas, seed and stover had higher S content when 100% NPK was applied along with biochar @ 7.5 t ha-1 and humic acid at 30 kg ha-1. Dehydrogenase activity at 30 DAS was significantly higher with 75% NPK in combination with humic acid. While, at 60 DAS and harvest, significantly higher activity was noticed with biochar @ 5 t ha-1 along with 100 % NPK and 75% NPK respectively with the corresponding activities of 20.72 and 5.594 μg TPF g-1 soil day-1 . Combined application of 75% NPK, 7.5 t ha-1 of biochar and 30 kg ha-1 of humic acid could result in a significantly higher acid phosphatase which was on par with recommended NPK along with biochar @ 7.5 t ha-1at all the stages of assay. Alkaline phosphatase activity highest at 30 and 60 DAS with 100 % NPK along with biochar @ 7.5 t ha-1, while at harvest stage higher activity was shown by 75% NPK alone. Biochar application showed a non significant increase in soil pH. Significantly higher EC was shown when 100% NPK was integrated with biochar @ 7.5 t ha-1. Soil CEC was significantly higher when 100% NPK was applied in combination with biochar @ 7.5 t ha-1 and humic acid. Such increase at later stages was not significant. Biochar elucidated a significant increase in organic carbon from 0.51 to 0.62 per cent at 30 DAS when applied at 7.5 t ha-1. Mean available N content (kg ha-1) significantly increased from 180.8 to 202.6 at 60 DAS and from 141.3 to 167.7 kg ha-1 at harvest with 7.5 t ha-1 of biochar. The resultant available P was significantly higher when integration was exercised with biochar @ 7.5 t ha-1 and humic acid with recommended level of NPK, the value being 66.5 kg ha-1. The higher available K content at 60 DAS (776 kg ha-1) and harvest stage (533 kg ha-1) was obtained with 75% NPK alone. Higher available S content was recorded at 30, 60 and harvest stages with combined application of the three factors. Highest B: C ratio (3.84) was obtained in treatment receiving 75 percent NPK with biochar @ 7.5 t ha-1. The benefits from biochar can be fully explored when applied along with RDF. At reduced level of NPK, biochar exerted positive and significant only upto 5 t ha-1, while at the highest level of 7.5 t ha-1, the integration with humic acid improve the soil properties, plant nutrients and crop yields.