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

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 andabiotic 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 K₂SO₄. 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.