Nickel (Ni) is an essential micronutrient for plants although it is considered toxic when present in excess in the soil. This study investigated the transfer of Ni from the soil to rice in terraced paddy fields affected by serpentinite, which contains an anomalously higher Ni content compared with other geological materials. Soils, soil solutions, and rice plants were collected at several different growing stages from three adjacent terraced paddy fields subject to the same water and fertilizer management. Temporal changes in their elemental compositions revealed that a higher concentration of Ni was dissolved in the soil solution during flooded conditions, probably due to the co-solubilization with Mn oxides under low redox potential conditions. However, rice accumulated Ni at a higher rate during the drainage period than in the flooding period. Although the Ni concentration in the soil solution was lowest in the drainage period, the relative concentration to Fe (i.e., Ni/Fe ratio) was much higher than that in flooded conditions. These relationships suggest that a potential measure to counter the transfer of Ni from the soil to rice in serpentine-affected paddy fields is to increase Fe phytoavailability during the drainage period.
Sediment that has deposited after the flood generated by the 2019 typhoon (referred to as Flood Sediment, FS) was collected along two rivers in eastern Fukushima Prefecture, Japan to determine the total and exchangeable radiocesium ( 137 Cs), and acid-extractable potassium (K) contents. Then, these FS parameters were compared with those of decontaminated soils (DS) in nearby agricultural fields to discuss the potential transfer risk of 137 Cs from rivers to nearby remediated soils. While FS had about four times higher total 137 Cs content, it showed a three-times lower exchangeable 137 Cs content than DS. Furthermore, acid-extractable K referred to as non-exchangeable K (Nex-K) content was high enough to restrict 137 Cs transfer from soil to crops for both FS and DS. From these comparisons, we concluded that deposition of FS onto DS may not increase the transfer of 137 Cs from soil to crops.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.