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应用梯度扩散薄膜技术评价天然富硒土壤中硒的生物有效性 被引量:1
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作者 吴超 孙彬彬 +3 位作者 陈海杰 成晓梦 贺灵 曾道明 《岩矿测试》 CSCD 北大核心 2022年第1期66-79,共14页
有效硒是评价土壤中硒对植物供给能力的重要指标,中国目前尚无测定土壤有效硒的统一方法。化学提取法、土壤溶液法常用于测定土壤有效硒含量,但存在缺乏普遍适用提取剂类型、目标态提取不完全和对非目标态溶解等问题。梯度扩散薄膜(DGT... 有效硒是评价土壤中硒对植物供给能力的重要指标,中国目前尚无测定土壤有效硒的统一方法。化学提取法、土壤溶液法常用于测定土壤有效硒含量,但存在缺乏普遍适用提取剂类型、目标态提取不完全和对非目标态溶解等问题。梯度扩散薄膜(DGT)技术是一种基于解离、扩散动力学的有效态测定方法,已有学者将其应用于土壤有效硒的测定并取得良好效果,但是否适用于天然富硒土壤中硒生物有效性评价尚不明确。为探明梯度扩散薄膜技术评价天然富硒土壤中硒生物有效性的可行性,本文以浙江省上墅乡和汾口镇分布的天然富硒土壤为研究对象,实验应用化学提取法、土壤溶液法和DGT技术[包括Fe-oxide(水铁矿型)DGT、Zr-oxide(水合氢氧化锆型)DGT]评价土壤中硒的生物有效性。结果表明:①Fe-oxide DGT测得的有效硒平均含量为0.17±0.076μg/L,Zr-oxide DGT测得的有效硒平均含量为0.20±0.13μg/L。两种类型DGT测得有效硒含量差异不大,但由于Zr-oxide DGT对Se^(4+)具有专性吸附特征,导致Zr-oxide DGT无法有效反映植物体内硒含量水平。对于检测土壤硒生物有效量,Fe-oxide DGT要优于Zr-oxide DGT;②植物体内硒含量C_(plant-Se)与三种方法测定的有效硒含量均呈显著正相关,但C_(plant-Se)与Fe-oxide DGT测定的有效硒含量相关系数(r=0.705)大于其他两种方法;③基于DGT技术计算得出的R值(土壤颗粒向土壤溶液补充硒的能力)和K_(d)值(土壤固相与液相之间的分配系数)表明上墅研究区相较于汾口研究区土壤中硒具有更强的迁移性,但其土壤固相向土壤溶液补充硒离子的速率小于汾口研究区。综上认为,对于评价天然富硒土壤中硒生物有效性而言,DGT方法优于化学提取法和土壤溶液法,在测试性能和反映土壤动力学过程信息方面更具优势。 展开更多
关键词 化学提取 DGT技术 土壤溶液法 生物有效性 天然富硒土壤
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Study on Water-Soluble Organic Reducing Substances. I. Determination of Organic Reducing Substances by Differential Pulse Voltammetry
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作者 WUYOU-XIAN DINGCHANG-PU 《Pedosphere》 SCIE CAS CSCD 1991年第2期157-167,共11页
A new method was proposed for study of organic reducing substances in soils. According to the theoretical relationship between the voltammetric behaviors and reduction-oxidation reaction of reducing substances, the wo... A new method was proposed for study of organic reducing substances in soils. According to the theoretical relationship between the voltammetric behaviors and reduction-oxidation reaction of reducing substances, the working conditions of differential pulse voltammetry (d.p. v.) for determining the organic reducing substances produced during the processes of the anaerobic decomposition of plant materials were established with a glass carbon electrode as working electrode, 1 M Ag-AgCl electrode with large area as reference electrode, 0.2 M NH4AC as supporting electrolyte and pH buffer solution, pulse amplitude (AE) of 25 mV, scan rate at 2 mV·S-1and scan potential ranging from -0.5 to +1.2 voltage(vs. M Ag-AgCl). The peak current proportional to the concentration of reducing substances, and the characteristic peak potential of each organic reducing substance were regarded as the quantitative and qualitative base, respectively. These results obtained under the conditions mentioned above directly reflect both the reducing intensity and capacity of the organic reducing system in soils. 展开更多
关键词 differential pulse voltammetry organic reducing substances peak current peak potential
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