Improving phosphorus uptake and wheat productivity by phosphoric acid application in alkaline calcareous soils

BACKGROUND Low phosphorus (P) efficiency from existing granular fertilisers necessitates searching for efficient alternatives to improve wheat productivity in calcareous soil. RESULTS Multi‐location trials have shown that phosphoric acid ( PA ) produced 16% higher wheat grain over commercial P fertilisers, i.e. diammonium phosphate ( DAP ) and triple superphosphate ( TSP ). Methods of P application significantly influenced grain yield and the efficiency of methods was observed in the order: PA placement below seed > PA , DAP or TSP fertigation > DAP or TSP broadcast. The sub‐surface application of PA produced highest grain yields (mean of all rates), i.e. 4669, 4158 and 3910 kg ha −1 in Bagh, Bhalwal and Shahpur soil series, respectively. Phosphoric acid at 66 kg P 2 O 5 ha −1 was found more effective in increasing gain yield over that of control. Trend in grain P uptake was found similar to that observed for grain yield. Maximum P uptake by grain was recorded at the highest P rate and the lowest at zero P. The significant increase in P uptake with P rates was generally related to the increase in yield rather than its concentration in grain. Phosphorus agronomic efficiency ( PAE ) and phosphorus recovery efficiency ( PRE ) were found higher at lower P rate (44 kg P 2 O 5 ha −1 ) and decreased with P application. However, PA applied by the either method resulted in higher PAE and PRE compared to DAP and TSP . CONCLUSION Phosphoric acid is suggested as an efficient alternative to commercial granular P fertilisers for wheat production in alkaline calcareous soils. © 2015 Society of Chemical Industry