Sustaining zinc bioavailability in wheat grown on phosphorus amended calcisol

The deficiency of zinc (Zn) and phosphorus (P) occurs widely in alkaline calcareous soils, and the antagonism between these two elements is also a major cause of low Zn uptake in wheat, leading to low productivity and quality. The present study investigated the different methods of Zn application for wheat cultivars [i.e. Faisalabad-2008 (Fsd-08) and Zincol] grown on P amended calcisol. Data regarding yield component, estimated Zn bioavailability and phytate content in grain were recorded. Compared to zero P control, application of phosphoric acid (PA) and di-ammonium phosphate (DAP) to wheat cultivar Fsd-08 increased biological yield by 49.1 and 76.4%, grain yield by 45.5 and 43.1%, and grain-P by 79.2% and 25.6%, respectively. The Zn-treatment (irrespective of mode of its application) produced higher grain Zn content, however, application of PA and DAP decreased grain Zn concentration by 26.5 and 30.5%, respectively relative to zero P treatments. Almost similar trend was observed in Zincol cultivar in terms of increase in yield parameters and grain-P and Zn content of wheat. The phosphate application also affected phytate to Zn molar ratio (PZR) which was usually found lower in Zincol (range: 12-35) while higher in Fsd-08 (range: 12-43). Overall, PA application was found to have higher beneficial effects in terms of increasing yield parameters and grain-Zn in wheat cultivars. In crux, the current investigation suggests that Zn application; especially foliar sprays sustained higher grain content while Zincol cultivar in particular accumulated higher grain-Zn grown on calcareous soils applied with phosphate fertilizers.