Influence of crop growth on ionic equilibria, selectivity and diffusion of cations in soil
Titel:
Influence of crop growth on ionic equilibria, selectivity and diffusion of cations in soil
Auteur:
Baligar, V. C.
Verschenen in:
Communications in soil science and plant analysis
Paginering:
Jaargang 16 (1985) nr. 2 pagina's 163-178
Jaar:
1985-02
Inhoud:
Plant species vary in their ability to absorb many major and minor nutrients and thus continually change ionic equilibria in soils. Experiments were conducted under controlled conditions to investigate the influence of corn, onion and wheat growth on the ionic equilibria, selectivity coefficient and diffusion coefficient of K, Ca and Mg in soil. Corn had the greatest shoot and root growth and root density while onions had the least. Addition of ? to soil enhanced corn growth and ? uptake, however no such relations could be seen with onions. Increasing the plant population of wheat per unit soil volume increased the root density and amount of K, Ca and Mg removed from the soil. With increasing age, all three crops reduced ? concentrations in the soil solution as well as on the exchange sites. With increasing age of corn and onion there was a depletion of Ca and Mg in soil solution but the concentration of these ions on the exchange phase was increased. The diffusion coefficients (De) of K, Ca and Mg were dependent upon the level of respective nutrient in the soil solution. The order of cation selectivity (k) in these soils was Ca > Mg > K. However, the magnitude of the selectivity coefficients, kK/Ca, kK/Mg and kCa/Mg varied among the crop species. Such variations are attributed to the differences in ion uptake properties of plant species under consideration.
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