A RADIO-PEDOLOGIC VIEW OF Ca/Al RATIOS IN NATURALLY RADIOACTIVE SOILS
2000
Langley-Turnbaugh, S. J. | Evans, C. V.
Radium is a potential Ca analog that may interact with Ca and Al in forest ecosystems. Many hectares of forested land in New England occur on soils with naturally high levels of radionuclides-including radium-but little is known about interactions of Ca, Ra, and Al in forest systems. Our objectives were: (i) to compare soil profile distributions of Ra, Ra, Ca, Mg, and Al and (ii) to examine correlations between Ra, Ra, Ca, Mg, and Al. We sampled 13 Haplorthods to determine activities of Ra and Ra, pedogenic radium deficiency, pH, and NH4Cl-extractable Ca, Mg, and Al. Aluminum concentrations were an order of magnitude higher than concentrations of Ca and Mg and several orders of magnitude higher than estimated concentrations of Ra. Profile distributions indicated that Ra and Ra deficiencies-and Ca, Mg, and Al concentrations-were greatest in E horizons and decreased with depth. pH increased with depth. Values of Ca, Mg, and Ra were highly variable in A horizons, and pH values were highly variable in A and E horizons. Several significant (P < 0.05) correlations were identified between extractable cations and radionuclide activities and deficiencies. In A horizons, deficiencies of both Ra isotopes were closely correlated to Mg concentration. In E horizons, Ra deficiency was significantly and negatively correlated to Al concentration. In spodic (Bhs and Bs) horizons, both Ca and Al were significantly and negatively correlated to Ra activity. Although Al clearly dominates this acidic environment and controls the chemistry of the soil system, significant interactions occur between known plant nutrients and radionuclides. This study also suggests that Ra, in addition to Ca and Mg, is being cycled by plants.
Show more [+] Less [-]AGROVOC Keywords
Bibliographic information
This bibliographic record has been provided by National Agricultural Library