赣南地区设施菜地土壤全硒含量分布特征

为探究江西省赣州设施菜地土壤全硒（Se）的含量及其分布特征，于2021年对赣南地区设施蔬菜大棚采集0～20 cm耕层土壤样235件，测定了土壤采样点的经纬度、海拔及土壤中全硒含量和理化性质。结果表明，赣南地区设施菜地土壤全硒质量分数平均为0.31 mg/kg，变化范围为0.03～1.25 mg/kg，全硒含量分布频率符合正态分布。研究区域设施菜地富硒土壤资源较为丰富，85.1%的样点数土壤全硒含量处于足硒及以上水平（>0.175 mg/kg），其中有22.1%的样点数土壤属于富硒水平标准（>0.400～3.000 mg/kg），而富硒土壤主要集中在赣南地区的正西部及东北部等部分区域；7.2%和7.7%的样点数土壤全硒质量分数分别达硒不足（>0.125～0.175 mg/kg）和潜在硒不足水平（≤0.125 mg/kg），二者主要集中在赣南地区西南角部分区域，不存在硒中毒区域。海拔每增加1 m，设施土壤全硒质量分数降低5.35×10-4 mg/kg；纬度每增加1°和pH值每增加一个单位，土壤全硒质量分数分别增加0.090和0.049 mg/kg。综上，赣南地区设施菜地土壤硒资源具有较大利用潜力，并可依据研究区域全硒含量分布特征开展具有针对性的设施富硒蔬菜发展策略。

Distribution characteristics of the total selenium content in greenhouse vegetable soil in southern Jiangxi Province of China

Selenium (Se) is one of the essential trace elements in the process of human nutrient metabolism. The Se deficiency can cause various health risks or disorders of the human body. Fortunately, there are abundant Se-rich soil resources in Ganzhou City of Jiangxi Province, China. It is a high demand to make the Se-rich agricultural products more popular in the markets. A production system of greenhouse vegetables has been one of the most intensive agro-ecosystems in recent years. The facility vegetable industry can be expected to serve as the second-largest pillar industry after Gannan navel oranges, as the facility steel frame greenhouses increased rapidly. However, the Se enrichment in the facility soil is still unclear in southern Jiangxi. It is very necessary to fully utilize the Se soil resources of facilities for the decision-making on the land use management. This study aims to explore the total Se content of greenhouse vegetable soil and the distribution characteristics in Ganzhou City, Jiangxi Province, China. 235 soil samples were collected from the 0-20 cm cultivated layer in the greenhouse vegetable bases in 2021. A geographic information system (GIS) was used to measure the latitude, longitude, and altitude of the soil sampling points. The total Se content was also measured to determine the physicochemical properties in the soil samples. The results showed that the average content of total Se was 0.31 mg/kg in the greenhouse vegetable field in the study area, where the variation range was 0.03 to 1.25 mg/kg. The distribution frequency of soil Se content was followed by the normal distribution. There were the relatively abundant Se-rich soil resources of the greenhouse vegetable plots. Specifically, the total Se content in 85.1% of the soil samples was at or above the level of sufficient Se (>0.175 mg/kg), of which 22.1% of the sample soils belonged to the Se-rich level standard (>0.400-3.000 mg/kg). The Se-enriched soil plots were mainly concentrated in the western and northeastern parts of southern Jiangxi. Only 7.2 % and 7.7 % of the total Se content in the soil samples were at the levels of Se deficiency (>0.125-0.175 mg/kg) and potential Se deficiency (≤0.125 mg/kg), respectively. Furthermore, the Se deficiency plots were distributed in the southwest corner of southern Jiangxi. There was no Se poisoning area. The correlation analysis showed that the total Se content of greenhouse vegetable soil was very significantly negatively correlated with the altitude (P<0.01). The total Se content decreased by 5.35×10-4 mg/kg, as the altitude increased by 1 m. By contrast, the soil total Se content was significantly positively correlated with the latitude and soil pH value. Moreover, the soil's total Se content increased by 0.090 and 0.049 mg/kg, respectively, as the latitude and pH increased by 1° and one unit, respectively. In conclusion, the soil Se resources of greenhouse vegetable fields can be widely expected to serve as the great potential for the promising prospect in southern Jiangxi. A recommendation can be proposed to effectively implement the targeted development strategy of greenhouse Se-enriched vegetables, according to the spatial distribution characteristics of soil total Se content in the study area. The finding can provide a strong reference to promote the high quality and green development of the greenhouse vegetable Se-rich industry in southern Jiangxi Province.