摘要
为探讨地下水位不同尺度波动幅度中氮素运移规律,室内通过土柱Ⅰ、Ⅱ和Ⅲ模拟地下水位的不同尺度上下波动进行对比试验。试验中柱Ⅰ水位保持静止、柱Ⅱ波动幅度为15 cm、柱Ⅲ波动幅度为30 cm,在实验装置相同情况下,得出三柱各土层中DO、NO-3-N和NH+4-N浓度变化。结果表明:柱Ⅰ中DO、NO-3-N和NH+4-N变化较小,而柱Ⅱ、Ⅲ中DO、NO-3-N和NH+4-N均变化较显著,且柱Ⅲ的变化幅度要大于柱Ⅱ。对比水位静止的柱Ⅰ,当水位上升和下降后,柱Ⅱ、Ⅲ各土层中DO和NO-3-N浓度均减小和增大,增减趋势相同,但DO和NO-3-N的变化幅度均为柱Ⅲ>柱Ⅱ;NH+4-N浓度相应地增大和减小,增减趋势相同,但幅度柱Ⅲ>柱Ⅱ。柱Ⅱ、Ⅲ进行两次循环波动后,两土柱各土层中NH+4-N均减小,且减小幅度柱Ⅲ>柱Ⅱ;NO-3-N无明显规律。可知,水位波动对土层中硝酸盐运移影响显著,且水位波动尺度与该影响程度相关,故在地下水硝酸盐污染风险评价时,不可忽视水位波动对氮素运移的影响。
In order to investigate the law of nitrate movement with the variation of water table fluctuation, three soil columns were set to simulate the different levels of water table fluctuation, i.e. column I（control test）, column I （fluctuation of 15 cm） and column I （fluctuation of 30 cm） in a laboratory comparative trial. In the same status of experimental installation, the change of DO, NO3^- -N and NH4^＋ -N concentration were tested in these columns respectively. The results showed that the change of DO, NO3^- -N and NH2-N concentration in the column II and i were more significant than that in the column I and the amplitude of variation in column m was larger than that in column II. Comparison with the rest level of column I, DO and NO3^- -N concentration changed correspondingly in a same increase-decrease tendency in column II and III with the water level rise and fall, and the change range in column m is more significant than that in column II. This law was also observed in the case of NH4^＋ -N concentration change. After two circular fluctuations, the concentration of NH2-N in column II and III decreased and the scope of decrease in column III was greater than that in column II. However, the NO3^- -N concentration had no obvious rule. Therefore, fluctuation can significantly influence the movement of nitrogen in soil column, and the degree of influence is related to the variation of water table fluctuation. Thus, during the groundwater nitrate contamination risk assessment, the influence of water table fluctuation on nitrate movement should not be neglected.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2013年第12期2443-2450,共8页
Journal of Agro-Environment Science
基金
2013年环保公益性行业科研专项"地下水污染源强评价、分类与防控技术研究"(201309003)
关键词
水位波动
波动尺度
硝态氮
铵态氮
运移
water table fluctuation, fluctuation variation, nitrate nitrogen, ammonium nitrogen, movement
