黑龙江省土壤硒分布及其影响因素研究

黑龙江省处于全国缺硒带的始端,为研究黑龙江省土壤全硒(Se)的含量、分布及其与土壤性质的关系,在全省采集400余个农业土壤0~20 cm耕层样品及主要类型土壤剖面样品(共21个剖面各发生层次土样71个),分析了土壤全硒含量、分布规律及其影响因素。结果表明,黑龙江省土壤全硒含量变幅为0.008~0.660 mg kg~(-1),平均值为0.147 mg kg~(-1),总体上处于缺硒及潜在缺硒土壤范畴,几乎不存在高硒土壤与硒毒土壤。不同类型土壤中以盐碱土含硒量最低(0.097 mg kg~(-1)),而泥炭土最高(0.273 mg kg~(-1));硒在土壤剖面中主要呈现表聚型分布,也有少数呈现双峰型和心土聚集型分布;不同区域以大兴安岭地区为最低(0.115 mg kg~(-1)),小兴安岭山地最高(0.198 mg kg~(-1));不同行政市以大兴安岭地区最低(0.115 mg kg~(-1)),黑河市为最高(0.228 mg kg~(-1))。回归分析表明:土壤全硒含量与土壤有机碳(SOC)、黏粒含量具有极显著正相关关系,与pH呈极显著负相关。研究区表土层土壤SOC、黏粒含量与pH是影响土壤硒含量的主要因素,此外土壤母质也是影响硒分布的重要因素;而土壤SOC含量对硒在土壤剖面中的分布与富集起到了至关重要的作用。

Distribution of Selenium and its Influencing Factors in Soils of Heilongjiang Province, China

Objective]Heilongjiang Province is the largest grain-producing province of China, and sits at the starting point of the Selenium(Se)-deficient belt of the country. In the light of the physical conditions and soil distribution in various regions of the province,agricultural soil samples,representative of the regions were collected for analysis of Se distribution and exploration of effects of soil physic-chemical properties on it,with a view to providing some providing scientific bases for the survey of environment background and the study of epi-geochemistry of soil selenium as well as human health.[Method]More than 400 soil samples from the topsoil layers(0~20 cm)of farmlands all over the province and 21 soil profiles of the major types of soils samples(21 of the province,together with 71 soil samples from genetic horizons of the profiles)were gathered and analyzed for content and distribution of soil Se and their relationships with soil properties,such as pH,SOC(Soil organic carbon)and PSD(Particle size distribution).[Result]Results show that the content of total selenium ranges from 0.008 to 0.660 mg kg-1 with a mean value of 0.147 mg kg-1,which means that on the whole the soils are in the category of Se deficiency or potential Se deficiency,with little in the category of high Se or excessive Se(Se-poisoning). Among the types of soils existing in the province,saline-alkali soil is the lowest in Se content(0.097 mg kg-1),while Peat soil the highest(0.273 mg kg-1);In most soil profiles Se accumulates mainly in the surface soil,and declines with soil depth,and in a few of them,Se distribution displays two peaks or one peak in the subsoil layer, too. Among the regions of the province,Daxinganling is the lowest in Se content(0.115 mg kg-1),while Xiaoxinganling the highest(0.198 mg kg-1). Among the administrative regions,Daxing’anling is the lowest (0.115 mg kg-1),while Heihe city the highest(0.228 mg kg-1). Correlation and regression analysis shows that soil Se content is significantly and positively related to soil total organic carbon(SOC)and soil clay content,but negatively to soil pH.[Conclusion]So,SOC content,clay content and soil pH are the main factors affecting selenium content of the topsoils in the studied area. Besides,soil parent material is also an important factor affecting the distribution of selenium in the soil. Whatever,SOC content plays a crucial role in the distribution and accumulation of Se in the profiles.