Objective To investigate the effects of phosphorus (P) deficiency and P fertilizer application on maize growth, P uptake, root traits, mycorrhizal colonization rate, and rhizosphere indexes in acid or calcareous soil.

Method Two different sources of acid soil (NX and WY) and two different sources of calcareous soil (SP and CP) were used in the pot experiment for maize with no P fertilization (low P, LP) or P fertilization (high P, HP) treatment. Maize plant dry weight, P weight, root traits (total root length, root surface area, root volume, average root diameter), mycorrhizal colonization rate, and rhizosphere indexes (rhizosphere pH, rhizosphere phosphatase activity, rhizosphere carboxylate content) were determined.

Result P deficiency seriously affected plant growth, and P application significantly increased plant dry weight and P weight of maize in acid or calcareous soil. P application significantly increased total root length, root surface area, root volume, and average root diameter, and reduced mycorrhizal colonization rate and rhizosphere carboxylate content of maize in both acid soil and CP calcareous soil. P application also significantly reduced rhizosphere acid phosphatase activity in NX acid soil and rhizosphere pH in CP calcareous soil. Principal component analysis showed that, under low P condition, maize root traits were positively correlated with plant dry weight and P weight, while rhizosphere carboxylate content and mycorrhizal colonization rate were negatively correlated with plant dry weight and P weight. Under high P condition, mycorrhizal colonization rate, alkaline phosphatase activity, rhizosphere pH, and average root diameter of maize were all positively correlated with plant dry weight and P weight.

Conclusion P fertilization can promote plant growth and P uptake of maize in different type of soil. The response of maize to P application is largely influenced by the background nutrient content in soil, and the soil with low P availability is more responsive to P fertilization. Maize mainly alters root traits to promote P uptake under low P condition.