处理污水中氮素在农灌黄土层中迁移转化规律研究
Study on the Transfer and Transformation Laws of Nitrogen within the Treated-Sewage Used for Irrigation in the Loess Layer

污水资源化是解决干旱半干旱地区农业用水紧缺的有效途径。本文通过现场土柱模拟试验，研究了经过处理并达到农田灌溉标准的城市生活污水用于农田灌溉，污水中剩余氮素在土壤中的迁移转化规律。结果发现，每次灌溉结束后，土壤中NH3-N浓度迅速下降，其中表土层下降最快，到灌溉后的第10天基本消失；土壤中硝态氮浓度在表土层、心土层和下包气带中达到峰值的时间分别约为灌溉后的第18、12和9天，且从表土层、心土层到下包气带层土壤中硝态氮含量峰值逐渐增大。另外，由于董志塬土层深厚、土壤偏碱性和且灌溉季节土温较高，处理污水用于农田灌溉不会造成地下水氮素污染。
Resource utilization of sewage is an effective way to solve the agricultural water shortage in the arid and semi-arid regions. Through on-site soil-column simulation experiments, the urban domestic treated-sewage that has reached the farmland irrigation standard is used for farmland irrigation, and the migration laws, as well as transformation laws of the remaining nitrogen of the sewage in the soil, are studied. It was found that after each irrigation, the concentration of NH3-N in the soil decreased rapidly, among which contained in the top soil layer declined the fastest, and it basically disappeared on the 10th day after irrigation. The concentration of nitrate-nitrogen reached the peak in the top soil layer, the core soil layer and the lower vadose zone layer was on the 18th, 12th, and 9th day after irrigation, respectively; and the peak values of nitrate-nitrogen content in the soil from the top soil layer, the core soil layer to the lower aeration zone layer gradually increased. In addi-tion, due to the deep soil layer in Dongzhiyuan, the alkaline soil and the higher soil temperature during the irrigation seasons, the use of treated-sewage for farmland irrigation will not cause groundwater nitrogen pollution.