摘要
利用连续浸提技术研究了江苏省低Se地区 3种土壤 (旱作土和太湖地区水稻土 )的Se含量及其形态分布。结果表明 ,3种土壤Se含量均偏低 ,尤其是长江沉积物发育的砂土属于贫Se土壤。对土壤Se形态分析表明有机物 硫化物结合及元素态Se是这些土壤中Se的主要存在形态 ,其次是残渣态 ,二者之和约占土壤总Se含量的 70 %～ 80 %。 5种形态中 ,除盐酸可提态Se趋向于向犁底层富集外 ,其他几种形态均为耕作层接近或高于犁底层。可溶态Se含量受其他形态Se影响较小 ,受土壤 pH值的影响较大 ;可交换态Se则相反 ,与除可溶态Se外的其他形态和土壤全Se含量均有显著正相关关系 ,但与土壤 pH值和土壤有机质无关。 5种有效Se浸提剂中 ,0 5mol/LNaHCO3 浸提的Se与植株含Se量有极显著正相关关系 。
Three types of soils in central Jiangsu Province was studied using seuential extraction techniques .The results showed that Se concentration of the tested soils is relatively low and the soils derived from sediments of Yangtze River fall in category of that for low-Se soils. Se extracted by 5%K 2S 2O 8-1:1HNO 3 is the predominated Se fraction in these soils, followed by residue Se, making a total contribution of 70%～80% of soil Se. Generally, Se is richer in the topsoil than in the plowpan except for Se exractaed by 2.5mol/L HCl. Water soluble Se concentration is shown to be affected by soil pH, while exchangeable Se is strongly positively related to other fractions except for to water soluble Se. Among the five extractants, only Se extracted by 0.5 mol/L NaHCO 3 is in close relation to shoot Se content. Thus 0.5 mol/L NaHCO 3 can be used as indicator of bio-available Se in these low-Se soils.The sum of Se extracted by 0.25 mol/L KCl and 0.7 mol/L KH 2PO 4 can also be used as indicator of bio-available Se in these low-Se soils.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2002年第3期355-359,共5页
Journal of Plant Nutrition and Fertilizers
基金
科技部 973项目 (G19990 1180 8 3)
江苏省科委项目 (BE 99315 )资助
关键词
江苏
低硒土壤
生物有效性
硒形态分级
low- Se soils
selenium fractionation
Se bio-availability
