Rooting System of Soybeans. II. Physiological Effectiveness as Nutrient Absorption Surfaces¹

Abstract

‘Aoda’ and ‘Harosoy 63’ soybeans [Glycine max (L.) Merr.], representing extremes in gross root morphology, were used in field and growth chamber experiments to study the influence of physiological characteristics of soybean roots on the absorption of nutrients. The efficiency of K uptake per unit root surface was found to be dependent on the variety and the solution concentration of K. The rate of K uptake per unit root surface, or K absorption potential, for Aoda roots was almost double that of Harosoy 63 roots at high levels of K but was nearly equal at low levels. The effect of K concentration on absorption potentials in nutrient solution was independent of concurrent variation of other nutrientions or total growth rate of the plants.

Variability of soybean germplasm in relation to phosphorus uptake and use efficiency

“…Differences in grain yield among soybean cultivars for phosphorus (P), potassium (K) and Nefficiencies were also reported by Raper & Barber (1970);De Mooy et al (1973); Sabbe & Delong (1998) ;Sarawgi & Tripathi (1998); Hanumanthappa et al (1998;1999) and Ogburia et al (1999), in field experiments. Spehar (1995a, b;1999) studied genetic differences in the accumulation of nutrients in leaves and seeds of tropical soybean cultivars from diallel crosses with the cultivars IAC-9, IAC-2, UFV-1, IAC-5, IAC-8, Vx5-281, IAC-7, Biloxi and Cristalina under high and low Al-stress.…”

Mineral Nutrition

“…The yield potential is an intrinsic factor and depends on plant germplasm characters that can be modified by selection and breeding (Furlani et al, 2002). Differences in grain yield among soybean cultivars under field conditions for P-, K-and N-efficiencies , were also reported by Raper andBarber (1970), De Mooy et al (1973), Sabbe & Delong (1998), Sarawgi & Tripathi (1998), Hanumanthappa et al (1998; and Ogburia et al (1999). Plant efficiency for phosphorus uptake and utilization may contribute to improve crop yield potential in situations of low P availability.…”

Occurrence and Correction of Manganese Deficiency in Plants

“…Rooting density is particularly important in well drained soils as movement of Mn, which occurs principally by diffusion, is slow under these conditions (45). Plants also vary in their ability to absorb Mn and translocate it to their shoots (82,120). However, Graham (40) concluded from a review of the literature that variations in functional requirement for Mn were insufficient to explain the large genotypic differences that have been observed.…”