Phosphorus requirements and nitrogen accumulation by three mungbean (Vigna radiata (L) Welzek) cultivars

Abstract

A promising approach for overcoming poor crop yields in phosphorus (P)-deficient soils is to exploit the genetic variation among plants to grow under low P conditions. We examined the P requirements of three mungbean cultivars, T-77, MI-5 and E-72, using four P rates, 0, 30, 60 and 90 mg P kg -1 soil (designated P0, P1, P2 and P3, respectively). Nodulation was highest in T-77, and unlike the other cultivars, nodule numbers were not increased by P application. Similarly, growth of T-77 was the highest, and was not influenced by P rates. In contrast shoot yields of MI-5 and E-72 at P0 were only 76 and 65%, respectively, of the maximum obtained under P application. Nodule dry weight and the amount of N fixed (Ndfa) in each cultivar was enhanced by P application, with T-77 generally giving the lowest response, and accumulating the highest Ndfa. The data suggest a higher P requirement for N 2 fixation (especially for T-77) than for growth. All plants increased their P uptake as P rates increased, with T-77 accumulating the highest amount of P at each P level. Differences in the physiological P use efficiency, PPUE (g shoot mg -1 P) among genotypes were generally not significant, neither were there any consistent trends as P rates changed. The ability to absorb P therefore appeared to be more important than PPUE in enhancing growth. We conclude from our data that it is possible by selection to obtain plants capable of good growth and high N 2 fixation in soils of low P; cultivar T-77 is a good example.

Field effect of P fertilization on N2 fixation rate of Ulex europaeus

“…2; see also e.g. [14] or [21]), which strengthen the likeliness of such a conclusion. Of course, P fertilization could nevertheless increase total N 2 fixation by increasing gorse biomass, but our results concerning P effect on gorse individual growth are not very conclusive under 120 kg P 2 O 5 .ha −1 .…”

Relationship between phosphorus status and nitrogen fixation by common beans (Phaseolus vulgaris L.) under drip irrigation

“…They agree with previous results obtained for the common bean (Vadez and Drevon 2001) and for the soybean (Gunawardena et al 1996) and Acacia mangium (Vadez et al 1997). The PUE concept, initially defined by Siddiqi and Glass (1981) and discussed by Gourley et al (1993), has gained scientific interest (Israel and Rufty 1988).…”

Comparison of phosphorus deficiency effects on the growth parameters of mashbean, mungbean, and soybean

“…Adu- Gyamfi et al (1989) reported that soybean was less tolerant to low P conditions when compared to pigeon pea. In a field study, however, Gunawardena et al (1992) suggested that on the average mungbeans may be more P-demanding than soybean.…”

“…Such variations may result in the contrasting response of host plant growth and nitrogenase activity to low P (Robson et al 1981;Jakobsen 1985;Israel 1987). It has been reported that since biological nitrogen fixation is reduced in crop species under low P conditions, consequently the general growth of the plants is adversely affected (Israel 1987;Gunawardena et al 1992).…”