Assessment of phytoavailability of Sr in an Andosol by addition of stable isotope

Abstract

Time-dependent changes of phytoavailability of Sr after adding it to the soil were studied for better prediction of radioactive Sr behavior in soilplant systems. Strontium-86 enriched stable isotope was added to a soil sample collected from a field of humus-rich Andosol. Plant uptake and extractability of Sr in the soil were assessed at given times after the addition during a 12-month period including repeated drying-rewetting. Proportion of the added Sr extracted by 1 M ammonium acetate solution from the soil was 45-58% throughout the period, which corresponded to that of long-time aged 90 Sr in the soil. Pot cultivations of orchardgrass (Dactylis glomerata) and red clover (Trifolium pratense) were carried out starting with uncropped soil for four weeks five times during the experiment. Clear time-dependent changes were not observed in uptake of the added Sr by the plants. Aging is unlikely to decrease Sr availability over time. The labile form of Sr determined with the isotopic dilution method was approximately 15% of total soil Sr, and more than the percentage of the extractable Sr in the soil. The results suggest that a part of the non-extractable forms of Sr in the soil would be available to the plant.

Assessment of the Copper Availability in the Arable Soils by Different Extractants

“…In the average DTPA extracted 10,87%, CaCl 2 0,31% and NH 4 NO 3 0,44% of the total soil Cu from the investigated soils. The amounts of extracted total Cu for all three single extractions are similar with typically reported for unpolluted soils [18,28,29]. shows the share of available Cu determined with all used extractants in the total Cu for the singular soil samples.…”

“…According to some studies [15,16], the DTPA-extractable metals are not plantavailable metals and therefore neutral salt solutions provide better relationship between soil-extractable metals and plant tissue accumulation. On the other side, numerous investigations showed that the selection of the best suitable extractant for the prediction of the plant uptake depends mainly on the environmental conditions [17,18].…”