Denitrification in Shallow Groundwater Below Different Arable Land Systems in a High Nitrogen‐Loading Region
Denitrification in Shallow Groundwater Below Different Arable Land Systems in a High Nitrogen‐Loading Region
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DOI：
10.1002/2017jg004199
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发表时间：
2018-03
期刊：
影响因子：
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通讯作者：
Wei Zhou;Yuchun Ma;R. Well;Hua Wang;Xiaoyuan Yan
中科院分区：
文献类型：
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作者：
Wei Zhou;Yuchun Ma;R. Well;Hua Wang;Xiaoyuan Yan
为了评估地下水中硝酸盐（NO3− − N）的风险，有必要了解反硝化能力。通过2年的观测，研究了中国东部地区3种耕地系统地下水反硝化能力。通过测定地下水中氧化亚氮（N2O）和二氮（N2）的浓度和分布模式，评价了地下水的反硝化能力。结果表明，葡萄园（VY）、菜地（VF）和稻田（PF）地下水反硝化活性较高，分别消耗了76%、83%和65%的NO3− − N。高反硝化活性可能是由于地下水中强还原性条件，高溶解碳浓度，促进反硝化作用。在采样期间，我们观察到高的二氮（过量N2）积累在地下水中，超过了总活性氮（N）在深层。在VY和VF中观察到的大量过量N2表明，相当多的N以气态N2的形式储存在地下水中，在反硝化作用高的含水层中平衡N预算时不应忽视。
To evaluate the risk of nitrate (NO3−‐N) in groundwater, it is necessary to know the denitrification capacity. In this study, observations were carried out for 2 years to investigate the groundwater denitrification capacity below three arable land systems in eastern China. Denitrification capacity was assessed by measuring the concentration and distribution patterns of nitrous oxide (N2O) and dinitrogen (N2) in groundwater. The results revealed that groundwater denitrification activity was high and consumed 76%, 83%, and 65% of the NO3−‐N in the vineyard (VY), vegetable field (VF), and paddy field (PF), respectively. The high denitrification activity might be attributed to the strong reducing conditions, with high dissolved carbon concentrations in groundwater, which promotes denitrification. During the sampling period, we observed high dinitrogen (excess N2) accumulation in groundwater, which exceeded the total reactive nitrogen (N) in the deep layer. The large amount of excess N2 observed in VY and VF indicated that considerable N was stored as gaseous N2 in groundwater and should not be ignored when balancing N budgets in aquifers where denitrification is high.