Effect of phosphorus and zinc application on zinc transformation and phyto-availability of zinc fraction in rice soil

Abstract

Application of high dose of phosphorus (P) changes the soil chemical properties which may lead to redistribution of Zn fractions in soil. A field experiment was conducted to study the effect of added zinc (Zn) and P on Zn transformations in a New Alluvial soil (Aeric Haplaquept), together with dry matter yield and Zn uptake by rice plants. The treatments included four levels of P (0, 40, 60, and 80 kg ha⁻¹) and three levels of Zn (0, 5, and 10 kg ha⁻¹). Although P application increased the dry matter yield of rice, Zn concentration and uptake was decreased significantly at higher dose of P application. Application of P caused a decrease in all the fractions of soil Zn except amorphous and crystalline Fe-oxide bound zinc. The order of preponderance of different zinc fractions followed the order, water soluble plus exchangeable (WE-Zn) < carbonate bound (Car-Zn) < organically bound (Org-Zn) < manganese oxide (MnOx-Zn) < crystalline sesquioxide (CFeOx-Zn) < amorphous sesquioxide (AFeOx-Zn) < residual Zn (Res-Zn). Residual Zn was the most dominant form of Zn, contributing about 69.07% to total Zn. Correlation data indicated that those fractions are in a state of dynamic equilibrium among different fractions and governs the plant-available Zn in soil. Path coefficient analysis of different Zn-fractions with Zn-uptake in rice plant showed that among the all pools of Zn, Org-Zn fraction plays the most vital role in contributing to Zn uptake by plants.

Keywords:

• Path analysis
• phosphorus
• rice
• zinc fractions
• zinc uptake
• Zn transformation

Acknowledgments

The authors are grateful for the financial assistance of All India Co-ordinated Research Project on ‘Micro- and Secondary Nutrients and Pollutant Elements in Soils and Plants’ funded by the Indian Council of Agricultural Research, Govt. of India for carrying out this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).