Zinc nutrition of wheat in response to application of phosphorus to a calcareous soil and an acid soil

Background and aims Although phosphorus (P) application is known to affect the zinc (Zn) nutrition of crops, the underlying mechanisms and effects of soil type are unclear. Methods A greenhouse pot experiment was conducted with wheat, two soils (calcareous and acid), and nine P fertilizer rates (0, 50, 100, 200, 400, 1000, 2000, 3000, and 5000 mg P 2 O 5 kg −1 soil). Results The effects of P application on the Zn content of shoots and roots in wheat and on the levels of available Zn in soil differed on the two soils. The wheat dry weight on both soils was highest with 2000 mg P 2 O 5 kg −1 . Total Zn accumulation was reduced above 2000 mg P 2 O 5 kg −1 on the acid soil and above 100 mg P 2 O 5 kg −1 on the calcareous soil. Available soil Zn declined when the Bray-P concentration reached about 34 mg kg −1 in the acid soil and when the Olsen-P concentration exceeded 200 mg kg −1 in the calcareous soil. Shoot Zn concentrations were negatively related to available soil P on the two soils. Conclusion The negative effects of increasing P application rates on Zn accumulation by wheat differed between the two soils. The effects showed no close relationship to available soil Zn.