Fixation reactions in calcareous soil reduce the concentration of soluble phosphorus (P) and affect crop growth. The study was aimed at finding out the reason that how pre-mixing of different P fertilizer sources [i.e. Diammonium phosphate (DAP), Phosphoric acid (PA)] with farmyard manure (FYM at 400 mg kg-1 soil) affect their availability in soil and thereby productivity of wheat crop. Various rates (at 0, 18, 36 and 54 mg P kg-1) of the fertilizers were tested alone (designated as PA & DAP) and along with the manure (PA+FYM & DAP+FYM). The amended soil was incubated for seven weeks (at 25±1 oC & 70% water holding capacity) and thereafter 32P dilution kinetics were measured using Freundlich kinetic model to describe gross amount of diffusible P ions present at soil solid (Pr). The experimental treatments induced change in Pr (ΔPr) values wherein the highest P application as PA+FYM produced maximum ΔPr (59%, over control), followed by DAP+FYM treatment (52%, over control). In greenhouse, highest P rate as PA+FYM produced maximum P use efficiency (24%), greatest P uptake (201.2 mg pot-1) and highest grain yield (44.1 g pot-1) of wheat. The results clearly suggest premixing phosphate fertilizer with FYM as a viable technique to increase P supply from soil and enhance productivity of wheat grown in alkaline calcareous soil. Mixing of phosphate fertilizer with FYM in calcareous soil was also evaluated to optimize P availability for improving productivity of wheat (Triticum aestivum). In second study, PA and DAP were applied to soil at 36 mg P kg–1, either alone or after mixing with double amount of FYM (i.e. 1:2 ratio on w/w basis). After 45-day incubation, P concentration in soil solution (Cp) and that of exchangeable P ions (E-value) present at solid-solution interface were determined to evaluate the impact on total plant-available pool. The FYM-amended fertilizers, i.e. PA+FYM and DAP+FYM showed highest values for Cp (3.2 and 2.7 mg P L–1, respectively) and E-value (114 and 97 mg kg–1 soil, respectively). Similarly, FYM-amended fertilizers produced higher P utilization and wheat yield as compared to their sole application. The PA+FYM (followed by DAP+FYM) exhibited maximum proportion of P derived from applied fertilizer (Pdff = 51.5 %) and greatest P actually taken up by wheat seedlings (L-value = 72.1 mg kg-1 biomass). Consequently, PA+FYM treatment produced highest grain yield (40.7 g pot–1), P uptake (162 mg pot–1) and P use efficiency (24.6%), which were generally at par with DAP+FYM treatment. The regression analysis revealed strong and positive correlation of L-value with grain yield (r =0 .86), biological yield (r = 0.84) and P use efficiency (r = 0.87) in wheat crop. In third study, two-years (2015-16 & 2016-17) field trials have shown that application of phosphoric acid (PA) at 54 kg P ha-1 along with farm-yard manure (FYM) produced maximum wheat grain (5159 kg ha-1) which was 23% higher over its sole application. Phosphorus uptake was increased with the increase in P rates (18, 36, 54 kg P ha-1) which was usually associated to higher grain yield than P concentration in grain. The manure amended inorganic P fertilizers were found more effective in P uptake and grain yield than their sole application. In greenhouse, a similar trend as occurred in field condition was observed for P recovery and biomass production. The manure amended PA (followed by diammonium phosphate) exhibited maximum P derived from applied fertilizer (Pdff = 40.03%) by a 45-day old wheat plant, as determined by 32P labelling technique. Efficiency of P fertilizers [i.e. P agronomic efficiency (PAE) and P recovery efficiency (PRE)] were found lowest at highest P rate (54 kg P ha-1). However, co-amended phosphate fertilizers showed higher PRE and PAE as compared to their sole application. Therefore, manure amended phosphate fertilizers application seems appropriate to attain higher P availability from soil, improve efficiency of inorganic fertilizers and enhance wheat productivity grown in alkaline calcareous soils