灌水频率对地下水埋深较浅土壤中溴和硝态氮迁移的影响

Effects of Irrigation Frequency on Movement of Bromide and Nitrate in Soil with Shallow Groundwater Table

采用人工土柱试验方法,研究了3种灌水频率下灌施到地下水埋深较浅土壤中的溴(Br-)和硝态氮(NO3--N)的迁移规律。结果表明,Br-和NO3-的迁移规律表现出良好的一致性,在相同灌水量下,随灌水频率的降低(除土表5cm土层),Br-、NO3-浓度峰均变胖、变缓,峰值降低,且Br-和NO3-峰向下迁移加快;灌水频率越高,土表Br-、NO3-含量降低越快,淋洗越彻底。随灌水总量的增加,各灌水频率土壤中Br-、NO3-浓度峰变胖、变缓,峰值降低。

Unreasonable irrigation is one of main reasons resulting in losses of large amounts of nitrate by leaching and groundwater pollution. The transportation of Br-and that were applied to soil column with shallow groundwater table under three irrigation frequency treatments was studied. The results showed that the movements of Br-and had a good consistency, and their concentrations were in line nearly with normal distribution. The distribution peak forms all became wider and more fatty, peak values reduced, and faster downward movement of their fronts, under the same amount of irrigated water on the soil column, when irrigation frequency was lowered (except for 5cm layer in soil surface). The higher the irrigation frequency, the decrease of both Br-and contents was faster, associating with more completely leaching. Br-and concentration peak forms all became wider and more fatty, and peak values reduced for all treatment when total irrigation quantity increased.