Assessment of urea coated with pomegranate fruit powder as N slow-release fertilizer in maize

ABSTRACT

It has been hypothesized that plant polyphenol plus lignin, cellulose, and hemicelluloses can immobilize/remineralize inorganic fertilizers, such as urea, better than polyphenol alone. To test this hypothesis, urea was coated with pomegranate (Punica granatum L.) fruit powder (containing polyphenol+lignin+cellulose) at rates of 0%, 30%, 70%, and 100% (w/w) of fertilizer urea. Fertilizer nitrogen was applied at 100 and 200 mg kg⁻¹ soil in a clay loam soil. This natural coating material, particularly at the rate of 100% (w/w), improved the distribution of mineral nitrogen (N) and available phosphorus (P) in soil during both early and advanced growth stages of maize and significantly increased total crop N and P uptake at both rates of fertilizer nitrogen compared to urea alone. The results suggest that urea coated with the powder of pomegranate fruit could potentially be an N slow-release fertilizer for use in better synchronizing crop N demand with soil N supply.

KEYWORDS:

• Polyphenol
• N immobilization
• N mineralization
• slow release urea

Acknowledgments

Special thanks go to Professor Torsten Mueller for his valuable supervision in the 6-month scholarship at Hohenheim University, which allowed the author to present this project to IFS. We greatly appreciate Dr. G. Amoabediny, Dr. M. Hosseini, and Mr. Shirvani (University of Tehran) for their support. We would also like to thank Akbar Sabahi for preparation the pomegranate peel.

Funding

This research was supported by the International Foundation for Science, Stockholm, Sweden, through a grant to Hossein Sabahi.