粤北山区连州市土壤硒含量分布特征及影响因素研究

以粤北山区连州市为研究区，采集了3009个耕地表层土壤（0~20 cm）样品，利用GS+软件构建的半方差变异函数模型、ArcGIS中的克里金插值法以及SPSS相关性分析等方法，分析了研究区耕地表层土壤硒含量的空间分布特征、硒元素的形态特征及影响因素.结果表明，土壤硒含量的均值为0.432 mg·kg^-1，变化范围为0.048~4.650 mg·kg^-1，耕地土壤整体处于富硒和足硒的水平，富硒土壤较为丰富.在空间分布上，富硒土壤主要连片分布在连州市的南部和东北部，中西部地区则呈斑状分布.土壤中硒的赋存形式主要以残渣态和强有机结合态为主，二者占全量的60.5%；土壤硒全量与残渣态硒、强有机结合态和腐殖酸结合态硒有显著的相关性.土壤pH和TOC对土壤硒含量具有重要的影响作用，而成土母质是影响连州市耕地表层土壤硒含量分布状况的决定性因素.

Selenium distribution in soils of Lianzhou city, mountain area of northern Guangdong Province and its influencing factors

3009 surface soil (0~20 cm) samples of farmlands were collected from Lianzhou, mountain area of northern Guangdong province, China. The selenium (Se) spatial distribution, morphology and influencing factors were analyzed by semivariogram model constructed by GS+, Kriging interpolation method in ArcGIS and correlation analysis by SPSS. The results showed that the average selenium content was 0.432 mg·kg^-1, ranging from 0.048 mg·kg^-1 to 4.650 mg·kg^-1. The farmlands in Lianzhou region, as a whole, are rich in selenium. According to the spatial distribution map, selenium-rich soil is mainly distributed in the south and northeast of Lianzhou city, while is scattered in the central and western regions. The main occurrence forms of selenium in soil are residual and strong organic bound forms, accounting for 60.5% of the total amount. Soil pH and TOC have an important effect on the selenium content, and parent soil is the decisive factor affecting the selenium distribution in the surface soil of Lianzhou city.