Evaluation of Extraction Methods for Plant-Available Soil Cadmium to Wheat by Several Extraction Methods in Cadmium-Polluted Paddy Field

Abstract

To develop a new method for the extraction of plant‐available cadmium (Cd), the correlation between the Cd content of polluted soil extracted with several extractants and the Cd content of wheat plants (variety “A”; Triticum aestivum L.) was examined. Among the HCI concentrations of soil extractants tested, the content of 0.025 mol L−1 HCI (HCl0.025)‐extractable Cd of soil showed a significant correlation with the Cd content of wheat grain and Cd uptake by shoot. The correlation between the soil Cd content extracted with 1 mol L−1 NH4Cl and the Cd content of wheat grain was nearly the same as that in the case of HCI0.025. In contrast, other reagents such as MgCl2, diethylenetriaminepentaacetate (DTPA) and tetra‐sodium pyrophosphate (Na4P2O7) could not give a good correlation between the extractable Cd content of soil and the Cd content of wheat grain. Therefore, it was considered that HCl0.025‐extractable Cd is a suitable indicator of the content of plant‐available Cd of soil to wheat. This extraction method can be applied to weakly acid Grey Lowland soil. Using the equation for the relation between the content of HCl0.025‐extractable Cd of soil and the Cd content of grain of the wheat variety “A”, the Cd content of grain of other 11 wheat varieties was evaluated. The wheat variety “A” showed the lowest absorption of Cd. The Cd content of variety “B” grain was located on the regression line of that of variety “A”, suggesting that both varieties exhibited the lowest ability to absorb Cd among the varieties tested. Grain yields of both “A” and “B” varieties were reasonably high. On the other hand, other varieties showed a substantially high ability to absorb soil Cd compared with the varieties “A” and “B”. The new method proposed for the determination of the content of plantavailable Cd proved to be suitable for the evaluation of plant‐available Cd of soil and also for the screening of wheat varieties with a high or low Cd accumulation capacity in grain.

Suppressive effect of magnesium oxide materials on cadmium accumulation in winter wheat grain cultivated in a cadmium-contaminated paddy field under annual rice–wheat rotational cultivation

“…Concentrations of Cd in the soil sample extracted with 0.1 mol L −1 HCl, named 'Cd AE ' (AE: Acid-Extractable), or 0.025 mol L −1 HCl, 'Cd PA ' (PA: Plant-Available), were also analyzed. The Cd PA in soil was reported to be significantly correlated with Cd contents in grains of winter wheat [25]. The extraction procedures were described in the previous report [19].…”

Cadmium Phytoremediation Potential of Napiergrass Cultivated in Kyushu, Japan

“…Wruk Wona was subjected to field trials in Cd-contaminated paddy fields (gray lowland soil) in 2011 in Kyushu, Japan, where the previous research was carried out in 2010 [11]. The source of Cd contamination in the soil was fallout dust from a neighboring zinc-refining plant [13,14]. The soil in these fields consists of clay loam (clay content 25%, silt content 22%, and sand content 53%).…”

Performances of Water Management, Foliage Dressing, and Variation Screening in Controlling the Accumulation of As and Cd and Maintaining the Concentrations of Essential Elements in the Grains of Rice Plant

“…The filtrates were collected and stored until analysis. Inductively coupled plasma-mass spectrometry (iCAP Qc ICP-MS, Thermo Fisher, San Jose, CA, USA) was used to determine the available element concentrations in the rhizosphere soil and the element contents in the digested soil and plant samples (Ibaraki et al, 2010).…”