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以潜育水耕人为土为供试土壤,以不同的处理方式和培养时间下产生的紫云英水溶性有机物(DOM)为添加物(包括新鲜紫云英DOM、淹水腐解7 d和14 d紫云英DOM、好气腐解7 d和14 d紫云英DOM;800 mg C·L-1),研究了5种DOM作为有机碳源促进淹水土壤中五氯酚(PCP)还原转化与Fe(Ⅱ)累积的关系。结果表明,紫云英DOM在淹水6.5 d后均可显著促进PCP的还原(P<0.05),淹水2 d后显著促进了乙酸钠提取态Fe(Ⅱ)[Fe(Ⅱ)NaOAc]和乙酸钠+盐酸连续提取态Fe(Ⅱ)[Fe(Ⅱ)NaOAc+HCl]的累积(P0.05);多数情况下还可促进乙酸钠提取态Fe(Ⅲ)[Fe(Ⅲ)NaOAc]的累积;多元线性回归分析发现,PCP还原主要受Fe(Ⅱ)NaOAc+HCl影响其逐步回归模型为:PCP(mg·kg-1)=22.95-0.047Fe(Ⅱ)NaOAc+HC(lmg·kg-1)(R2=0.615,P<0.01)。因此,DOM促进了淹水土壤中PCP还原与铁还原,Fe(Ⅱ)累积是导致PCP还原转化的主要化学机制。
The soil was immersed in hydroponic man-made soil and treated with different treatments and DOM as supplements (including DOM of fresh veins, flooding and decomposing for 7 d and 14 DOM for DOM, 7D for DOM and 14 DOM for DOM; 800 mg C · L-1), five kinds of DOM as organic carbon sources were used to promote PCP reduction in flooded soils Relationship between transformation and accumulation of Fe (Ⅱ). The results showed that DOM of Astragalus mongolica significantly promoted the reduction of PCP after submerged for 6.5 days (P <0.05). After 2 days of flooding, DOM of Fe (Ⅱ) [Fe (Ⅱ) NaOAc] and The accumulation of Fe (Ⅱ) [Fe (Ⅱ) NaOAc + HCl] in continuous extraction of sodium acetate + hydrochloric acid (P <0.05) also promoted the accumulation of Fe (Ⅲ) [Fe Cumulative linear regression analysis showed that the PCP reduction was mainly affected by Fe (Ⅱ) NaOAc + HCl. The stepwise regression model was PCP (mg · kg -1) = 22.95-0.047Fe (Ⅱ) NaOAc + HC (lmg · kg- 1) (R2 = 0.615, P <0.01). Therefore, DOM promoted the reduction of PCP and iron in flooded soil, and the accumulation of Fe (Ⅱ) was the main chemical mechanism leading to the reduction and transformation of PCP.