In the world, many studies have focused on the natural radioactivity in agricultural soils and food crops and the transfers of radionuclides between two components. However, the influence of long-term agricultural practices on the activity concentrations of radionuclides in the soils remains unclear. On the other hand, the soil-to-plant transfer factors of radionuclides for a specific plant type are different between the regions of the world. In this study, activity concentrations of natural radionuclides in 16 rice and corresponding soil samples in the Mekong Delta region of Vietnam were measured by a gamma spectrometer with a high purity germanium detector. The accumulation rates of radionuclides were predicted by using a model based on the balance between input and output rates of radionuclides in the topsoil. Based on the analysis of radionuclides in soil and rice samples, the average values of TF estimated for ⁴⁰ K, ²²⁶Ra, ²³²Th, and ²³⁸U were 4.2 ± 0.5 × 10⁻², 3.2 ± 0.6 × 10⁻², 4.6 ± 1.1 × 10⁻³, and 1.9 ± 0.4 × 10⁻², respectively. For long-term assessment, the annual rates 39 ± 2 Bq kg⁻¹ year⁻¹, 26.8 ± 2 mBq kg⁻¹ year⁻¹, − 418 ± 34 mBq kg⁻¹ year⁻¹, and − 358 ± 30 mBq kg⁻¹ year⁻¹ were estimated for ⁴⁰ K, ²²⁶Ra, ²³²Th, and ²³⁸U, respectively. From the results of this study, it is evident that irrigation system is the main factor that caused accumulations of radionuclides in the soil. Water leaching and rice uptake were two processes that were responsible for the rejection of radionuclides from the soil. The accumulation rates of radionuclides are therefore controlled by changing the cultivation conditions.

在世界范围内，许多研究集中在农业土壤和粮食作物中的天然放射性以及放射性核素在两种成分之间的转移。然而，长期农业实践对土壤中放射性核素活度浓度的影响仍不清楚。另一方面，特定植物类型的放射性核素从土壤到植物的转移因子在世界各区域之间是不同的。在这项研究中，使用配备高纯度锗探测器的伽马光谱仪测量了越南湄公河三角洲地区 16 种水稻和相应土壤样品中天然放射性核素的活度浓度。放射性核素的积累率是通过使用基于表土中放射性核素输入和输出率之间平衡的模型来预测的。⁴⁰  K、²²⁶ Ra、²³² Th和²³⁸ U分别为4.2±0.5×10 ^-2、3.2±0.6×10 ^-2、4.6±1.1×10 ^-3和1.9±0.4×10 ^-2。对于长期评估，年率 39 ± 2 Bq kg ^-1 年^-1、26.8 ± 2 mBq kg ^-1 年^-1、- 418 ± 34 mBq kg ^-1 年^-1和 - 358 ± 30 mBq kg ⁻¹ 年⁻¹估计为⁴⁰  K、²²⁶ Ra、²³² Th 和²³⁸U，分别。从这项研究的结果可以看出，灌溉系统是导致土壤中放射性核素积累的主要因素。水浸出和水稻吸收是导致土壤中放射性核素被排斥的两个过程。因此，通过改变培养条件来控制放射性核素的积累率。