Enriching cationic micro-nutrients concentration in basmati rice through potassium fertilization

Abstract

Field trials were conducted over two years at ICAR–Indian Agricultural Research Institute, New Delhi, to examine the effect of different rate, time, source and method of potassium fertilization on the uptake of Fe, Cu, and Zn by basmati rice under aerobic rice system. The study found that, with the exception of K fertilizer source, application timing, method, and rate significantly affected the uptake and translocation of Fe, Cu, and Zn in rice, with all three nutrients showing higher concentrations in straw than in grain across all treatments. The grain nutrient concentration improved with K application rates up to 60 kg K₂O/ha, beyond which the effect was insignificant. Split application of K fertilizer in two doses of 30 kg K₂O/ha each resulted in 7.1%, 2.3%, and 1.7% (pooled data) increase in grain Zn, Fe, and Cu concentrations, respectively, compared to basal application of 60 kg K₂O/ha. The foliar sprays of K (2.5%) during active tillering and panicle initiation, along with basal (45 kg K₂O/ha), had a statistically equivalent effect to that of two split applications of K. The harvest index (ratio between the amounts of nutrient stored in the grain to the total nutrient uptake by the plant) for Zn (21–26%), Fe (10–13%), and Cu (17–21%) indicates that only one-fourth, one-tenth, and one-fifth of the absorbed nutrients are transported to the grain, respectively. Thus, best K fertilization in aerobic rice increases uptake of Zn, Fe, and Cu from soil, enhances remobilization from straw to grain thereby improves grain nutritional quality.

Keywords:

• Basmati rice
• copper
• iron
• micro-nutrient
• potassium
• zinc

Acknowledgements

The first author duly acknowledge the financial support and express the gratitude to the Division of Agronomy, ICAR–Indian Agricultural Research Institute, New Delhi, India, for providing the facilities during the course of investigation.

Availability of data and material

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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Consent for publication

The necessary permission for publication is obtained from PME cell, IARI, New Delhi.

Ethics approval

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Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was financially supported by ICAR–Indian Agricultural Research Institute, New Delhi, India.