河南农业科学 ›› 2021, Vol. 50 ›› Issue (7): 57-65.DOI: 10.15933/j.cnki.1004-3268.2021.07.008

• 农业资源与环境 • 上一篇    下一篇

Zn 污染对石灰性水稻土Fe 氧化和还原的影响

范浩隆1,王旭刚1,2,孙丽蓉1,赵旭1,郭大勇1,石兆勇1,3   

  1. (1. 河南科技大学农学院,河南洛阳471000;2. 洛阳市植物营养与环境生态重点实验室,河南洛阳471000;3. 洛阳市共生微生物与绿色发展重点实验室,河南洛阳471000)
  • 收稿日期:2021-01-01 出版日期:2021-07-15 发布日期:2021-07-15
  • 通讯作者: 王旭刚(1978-),男,河南南阳人,副教授,博士,主要从事土壤化学研究。E-mail:nywxg@126.com
  • 作者简介:范浩隆(1996-),男,河南洛阳人,在读硕士研究生,研究方向:土壤化学。E-mail:fhl9696@163.com
  • 基金资助:
    国家自然科学基金项目(U1504402,41601309)

Effects of Zn Contamination on Fe Oxidation and Reduction in Calcareous Paddy Soil

FAN Haolong1,WANG Xugang1,2,SUN Lirong1,ZHAO Xu1,GUO Dayong1,SHI Zhaoyong1,3   

  1. (1. Agricultural College,Henan University of Science and Technology,Luoyang 471000,China;2. Luoyang Key Laboratory of Plant Nutrition and Environmental Ecology,Luoyang 471000,China;3. Luoyang Key Laboratory of Symbiotic Microbes and Green Development,Luoyang 471000,China)
  • Received:2021-01-01 Published:2021-07-15 Online:2021-07-15

摘要: 为明确重金属Zn对土壤中铁氧化还原过程的影响,利用外源加入ZnSO4•7H2O溶液的方法模拟黄河中游水稻土Zn污染,通过室内土壤淹水厌氧培养试验研究培养过程Fe(Ⅱ)的动态变化,分析铁的氧化还原状况;借助修正的欧共体标准物质局提出的三步提取法(BCR分级法)测试光、暗培养前后Zn的存在形态,探讨可还原态Zn的形态转化;借助总有机碳分析仪和气相色谱分别测试培养前后水溶性碳含量的变化和培养结束后的CO2和CH4,分析Zn污染土壤的碳素矿化情况。结果表明,Zn污染后Fe(Ⅲ)还原过程的还原容量降低,且降幅随污染程度而增加。光照时土壤中存在Fe(Ⅱ)氧化过程且该过程受Zn污染程度影响。Zn污染后不仅Fe(Ⅱ)氧化量由2.96 mg/g降低至0.91~1.71 mg/g,降幅随污染程度而增加,而且Fe(Ⅱ)氧化速率、Fe(Ⅱ)氧化率均随污染程度加深显著降低。30 d培养结束后污染土壤中Zn可被二乙基三胺五乙酸(DTPA)提取量显著降低且与光照条件有关,避光和光照培养后分别有98.09%、85.21%的外源加入Zn不能被DTPA所提取。综上所述,Zn污染抑制土壤中铁还原和亚铁氧化过程,抑制幅度随污染程度加深而增加;外源加入的Zn在避光铁还原过程可由弱酸提取态Zn向可还原态Zn转化。

关键词: 水稻土, Zn污染, 亚铁氧化, 厌氧还原, 重金属, 二乙基三胺五乙酸(DTPA), 碳素转化

Abstract: In order to clarify the effect of heavy metal Zn on iron redox process in soil,calcareous paddy soil sampled from the middle reaches of the Yellow River was contaminated with the addition of ZnSO4•7H2O solution,anaerobic slurry incubation was conducted in the experiment to study the dynamic change of Fe(Ⅱ)in the process of incubation,and the redox status of iron was analyzed. The modified BCR protocol was employed to measure Zn morphology in soils before and after incubation under illuminated and dark conditions to discuss phase transformation of reducible Zn. Water soluble organic and inorganic carbon in soils,CO2 and CH4 in the headspace were evaluated using total organic carbon analyzer and gas chromatography respectively to clarify carbon mineralization in soil contaminated with Zn. The results showed that reduction capacity of Fe(Ⅲ)in soils decreased by Zn contamination,and the decreasedamplitude enlarged with elevation of Zn pollution level. Ferrous oxidation appeared in soil incubated under illumination,and was hindered by Zn contamination. Fe(Ⅱ)oxidation amount declined from2.96 mg/g to 0.91—1.71 mg/g,and the decrease enlarged with elevation of contamination level. Velocity of Fe(Ⅱ)oxidation and percentage of Fe(Ⅱ)oxidized both decreased significantly with increase of Zn pollution. Diethylenetriaminepentaacetic acid extractable Zn in contaminated soil decreased after 30 d of incubation,and the extractability was related to incubation conditions. 98.09% and 85.21% of externally added Zn in soils incubated under dark and illuminated conditions could not be extracted by diethylenetriaminepentaacetic acid respectively. In conclusion,both iron reduction and ferrous oxidation in calcareous paddy soils were impeded by zinc contamination,and the inhibition was promoted with elevated Zn pollution level. Externally added Zn in soils incubated darkly would transform from weak acid
extractable Zn to reducible Zn.

Key words: Paddy soil, Zn pollution, Ferrous oxidation, Anaerobic reduction, Heavy metal, Diethylenetriaminepentaacetic acid(DTPA), Carbon transformation

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