兰州碱性土壤与农产品中硒分布及形态研究

通过对兰州市主要农业区表层土壤总硒有效硒调查和部分农产品总硒有机硒测定,研究了兰州市碱性农田土壤与农产品中硒的积累特征和分布规律。结果表明,兰州市农田表层土壤pH 8.39±0.26,总硒含量为(0.179±0.066)mg/kg(n=473),处于全国中等水平。全市土壤总硒含量区域性差别较大,市辖区明显低于三县,榆中县居全市之首。土壤有效硒与总硒含量显著正相关,有效硒占比为4.63%～15.8%,平均8.27%。农产品中玫瑰(Rosa rugosa),部分西兰花(Brassicaoleracea var.italica)和芹菜(Apium graveolens)样品硒含量高于0.015 mg/kg,为该市天然富硒农产品。农产品中有机硒占总硒比例较高,均值为73.4%。从区域整体来看,土壤硒含量较高的县区农产品硒含量相对也较高,适合富有机硒优质农产品开发。

Spatial distribution and speciation of selenium in alkaline soils and agricultural products of Lanzhou

To know the spatial distribution of soil total Se and Se speciation in agricultural products,totally 473 Lanzhou soils and 122 agricultural products were sampled and analyzed.The results showed that the average total Se concentration of the topsoil in Lanzhou was(0.179±0.066) mg/kg(n=473),which ranked in middle level of China.Soil pH value was 8.39±0.26.Soil Se varied significantly among sampling sites,and the highest averaged soil Se was found in Yuzhong Area.The bioavailable Se of soils ranged from 4.63% to15.8%,averagely 8.27% of the total Se.A significantly positive correlation between bioavilable Se and toal Se in soils was observed.For the agricultural products,the total Se in rose(Rosa rugosa),Chinese wolfberry(Lycium barbarum),broccoli(Brassica oleracea var.italica) and celery(Apium graveolens) exceeded 0.015 mg/kg(a standard value for Se-enriched products in China).The organic Se covered averagely 73.4% of the total Se in these agricultural products.Generally,the areas with higher soil Se in Lanzhou could grow higher Se products.Because of alkaline properties of Lanzhou soil,it has a significant advantage in developing Se biofortification agricultural products.