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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 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. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to examine the effect of co-application of phosphorus (P) and/or potassium (K) fertilizer to a soil layer on Mung bean (Vigna radiata R. Wilczek) grown in a Yellow Chromosol soil. We hypothesized that adding K to a P- enriched soil layer would increase recovery of K due to increased root proliferation. Layers enriched with P, K or a combination of P and K were placed at either 5 or 20 cm depth in 50 cm deep pots, and a uniform PK application treatment included for comparison. Mung bean was grown for 45 days and key growth and nutrient uptake attributes were assessed. Phosphorus application increased shoot and root dry matter yield and shoot yield was 40% higher in the shallow P treatment and 77% higher in the shallow PK than in the uniform PK treatment. Shallow co-application of P and K increased shoot P and K content compared with shallow P alone. Apparent P fertilizer recovery (%PAFR) followed the same pattern, and there was an 8 to 12-fold increase in %KAFR. There was no evidence of an increase in either the proportion or mass density of roots in the enriched soil layers in any treatment. P and K fertilizer use efficiency was maximized by co-application in an enriched soil layer. When multiple nutrient deficiencies occur co-application of nutrients in a soil layer accessible to roots maximizes fertilizer use efficiency. [ABSTRACT FROM AUTHOR]

Context: Previous research using soil has shown that mung bean (Vigna radiata L.) exhibits minimal root length response to elevated soil solution P concentrations, so does P uptake rate compensate? Aim: We hypothesized that when a mung bean plant growing in a nutrient solution low in P accesses a short-term adequate P supply it would increase P uptake through root plasticity. Methods: Mung bean seedlings were grown for 33 d in nutrient solutions with P concentrations of ranging from 1.6 to 6.6 mg L−1 and then transferred to an 8.2 mg L−1 P, 32P labeled solution and plants harvested 4 and 9 d after transfer. Key results: Plant growth and P uptake were increased by increasing short-term P supply. P uptake from the transfer solution doubled in the low P plants between 4 and 9 d, while in the high P plants there was a 2.5-fold increase. After 9 d in the transfer solution, 26.0% of the P in the low P plants was derived from the transfer solution compared to 18.3% in the high P plants. Between 4 and 9 d, total root length doubled in the low P plants and there was no significant increase in the high P plants. Conclusion: The results indicated that an increase in fine root length was the primary mechanism responsible for the increased P uptake upon transfer to a high P solution. Implications: In low P soils banding of P will result in increased root and shoot growth in mung beans. [ABSTRACT FROM AUTHOR]

Nutritional responses of tap-rooted legume species in glasshouse studies are often confounded by soil volume. This glasshouse pot experiment was conducted to determine root distribution and phosphorus (P) nutritional requirements of mungbean (Vigna radiata L.) as influenced by available soil volume in a sandy loam soil. In the experiment, mungbean was grown under increasing soil volume with pot depths up to 150 cm. Root biomass increased with soil volume. Root mass density in the upper 25 cm was highest in 50 cm deep pots, accounting for ∼3, 2 and 1.2 times that of 100 and 50 cm and 25 cm pots, respectively. Shoot P content was closely associated soil volume (r2 = 0.99). Phosphorus uptake in shoot per unit root mass in 50 cm pots was ∼1.6 times that of 150 cm deep pots. It is recommended that mungbeans should be grown in pots at least 50 cm deep to obtain realistic growth and nutrient uptake data. [ABSTRACT FROM AUTHOR]