Plants have diverse strategies to cope with phosphorus (P) deficiency.To better understand how maize responds to P deficiency,a field experiment with two P levels,0 and 100 kg P2O5 ha-1 (P0 and P100,respectively),was carried out as a part of a long-term Pfertilizer field trial.Plant and soil analyses showed that P-deficient maize reduced its growth rate,increased P use efficiency,and formed more thin roots with the diameter less than 0.6 mm at jointing and silking stages,compared to the plants treated with P100.Further,there were no differences in major inorganic P fractions (Ca2-P,Ca8-P,A1-P,Fe-P,occluded P and Ca10-P) between the rhizospheric and bulk soils at each harvest,even when soil Olsen-P was only 1.38 mg kg-1.These results suggested that maize responded to P deficiency by reducing the internal P demand for growth and increasing P acquisition ability by favorable root morphological alteration at low carbon cost.