废水灌溉对芦苇地土壤水文特征的影响

为研究造纸废水灌溉对黄河三角洲内陆盐碱芦苇地土壤水文特征的影响，通过设置芦苇地不同废水灌溉次数下的随机区组试验，采用田间测量土壤入渗过程和实验室内测定水文物理参数相结合的方法，分析造纸废水灌溉前后土壤pH值、含盐率及土壤水文物理参数的变化。结果表明：1）废水灌溉后，土壤pH均值降低6.0%；废水灌溉1～2次，土壤含盐率降低11.7%，废水灌溉3～4次后，增壤含盐率增加12.6%。2）废水灌溉后土壤体积质量均值减小6.5%，总孔隙度均值增大18.1%；随着废水灌溉次数的增多，土壤体积质量和总孔隙度分别有减小和增大的趋势。3）Horton模型比较适合描述废水灌溉后芦苇群落的土壤入渗过程，废水灌溉降低了初渗率，但随着废水灌溉次数的增多，稳渗率增加明显。4）废水灌溉增强了土壤贮蓄水分的能力，废水灌溉3次吸持贮水量达到最高（90.15 mm），灌水4次滞留贮水量达到最高（4.51 mm）。与未灌溉相比，废水灌溉具有明显的压碱抑盐、改良土壤水文物理性状、提高土壤入渗和贮水能力的作用，但不同灌溉次数处理间差异性显著。该研究为黄河三角洲内陆盐碱地区芦苇群落在造纸废水灌溉下的适宜灌溉次数和灌溉水量的确定提供了科学依据，有利于造纸废水资源的合理化开发利用。

Effect of wastewater irrigation on soil hydrological properties in reed marsh

To study the effect of papermaking wastewater irrigation on soil hydrological properties in saline reed field, different wastewater irrigation frequencies were employed in the saline reed field of Yellow River Delta. Soil infiltration course and hydrological properties were determined in field and laboratory. After wastewater irrigation, the change of the soil pH value, soil salt content and soil hydrologic-physical properties were observed. The results were showed that: 1) After wastewater irrigation, the mean reduction of soil pH value was 6.0%. In 1 irrigation time and 2 irrigation times treatments, soil salt content decreased by 11.7%, and soil salt content increased by 12.6% in 3-4 irrigation times treatments. 2) After irrigation, the mean reduction of soil bulk density was 6.5%, and the mean increment of soil total porosity was 18.1%. With the irrigation frequency increasing, soil density was decreased and soil total porosity was increased. 3) Soil infiltration course of reed field irrigated by wastewater fitted Horton infiltration model well. After wastewater irrigation, the first infiltration rate decreased, but the stable infiltration rate promoted with the wastewater irrigation frequency increasing. 4) Soil water-holding capacity was increased by wastewater irrigation. The maximum water-holding capacity in capillary was 90.15 mm in the treatment of irrigation 3 irrigations, and the maximum water-holding capacity in non-capillary was 4.15 mm in treatment of 4 irrigations. The papermaking wastewater irrigation had obvious benefits to reduce soil salinity, improve soil hydrologic-physical properties and enhance soil infiltration and water-holding capacity. However, there was the significant different in soil properties between treatments. These results provide the scientific basis for determining suitable irrigation frequency and the irrigation volume of papermaking wastewater in saline reed field of Yellow River Delta, which is of great significance to the exploitation and utilization of papermaking wastewater resources.