Shoot and Root Responses of Mung Bean (Vigna radiata L.) to Phosphorus Fertilizer Placement with Different Potassium Sources

ABSTRACT

Mung bean (Vigna radiata L.) is a major pulse crop in many parts of the world, but its yields are generally lower than other pulse crops due to biotic and abiotic stresses, including nutrition. An experiment was conducted to examine the effects of localized application of phosphorus (P) (³²P labeled P fertilizer) and different sources of potassium (K) (KNO₃, KCl, K₂SO₄ and KH₂PO₄) on shoot and root growth of mung bean, nutrient uptake and applied P and K recovery on a sandy loam Yellow Chromosol soil with low P and K status. Among the K sources highest shoot and root yield was obtained with K₂SO_4. Similarly, total plant P and the percentage of total P content obtained from the fertilizer (Pdff) was highest in this treatment. P application resulted in an increase in root length/soil mass, root mass density both inside and outside the band and in the percentage of roots in the fertilizer band. Each of the above parameters was numerically highest in the P+K₂SO₄ surface applied treatment. Root growth in the banded P resulted in better mung bean growth and nutrient uptake which was associated with stimulated root growth in the band and/or through increased uptake of P per unit root length. Co-application of K with P did not stimulate P uptake. Since co-application of P and K did not result in a synergistic response to either nutrient separation of these nutrients can be practiced.

KEYWORDS:

• ³²P isotope
• localized nutrient supply
• nutrient uptake
• P and K recovery
• root response

Acknowledgements

The granting of an Australia Award Scholarship from AusAid to the senior author to undertake this study is acknowledged. The assistance of Michael Faint for support during the crop growing and harvesting activities, and maintenance of the glasshouse is acknowledged as is the technical support of Leanne Lisle and Jan Carruthers.

Disclosure statement

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

Data availability statement

Data is available from the corresponding author.

Additional information

Funding

Australian Agency for International Development