【摘要】 用模拟土柱的方法对黄淮海平原主要土壤类型中硝态氮垂直运移的影响因素进行了研究。结果表明:在水分饱和条件下,硝态氮的垂直运移过程主要受土壤粘粒含量的影响,随着粘粒含量的增加硝态氮出流的时间推迟,硝态氮的穿透曲线的峰值变低、峰面分布变宽;在非饱和条件下硝态氮的穿透曲线变得不规则,有明显的拖尾现象,硝态氮运移的时间增长,穿透曲线变得平缓;示踪剂的流速对硝态氮运移有较大的影响,流速大的穿透曲线峰值高于流速小的穿透曲线峰值,且出流的时间和达到平衡的时间提前;不同价态阳离子由于带的电荷量不同,对硝态氮运移略有影响,表现为与硝态氮结合的高价阳离子产生的穿透曲线的峰值略高于低价阳离子;不同浓度的硝态氮示踪剂对硝态氮运移也有影响,在重力势和溶质势的共同作用下,浓度越高出流速度越快,穿透曲线峰值也高,完成出流的时间也迅速。更多还原

【Abstract】 The influence factor of nitrate vertical transport with simulated soil column in main soil groups of HuangHuaiHai plain was studied. The results were as follows: the process of nitrate vertical transport in saturated condition was affected by clay content. As the clay content increased, the outflow of nitrate was retard; the peak value and area of the breakthrough curve decreased and became wide respectively. Under unsaturated condition, the breakthrough curve was not regulation and had obviously nonsymmetrical. The duration of the transport was affected greatly by the fluxes of tracer. The peak value of breakthrough curve in large flux was higher than that of breakthrough curve in small flux. The time of outflow and reaching balance was advance. The different valence of cation had slightly influence on the nitrate transport. The peak value of the breakthrough curve of the high valence cation combined with nitrate was higher than that of the low value cation. The nitrate tracer in different concentration also affected to the nitrate transport. As the together function of gravitational potential and solute potential, the higher nitrate concentration was, the quicker speed of outflow was. The peak value of the breakthrough curve was also high and the time of outflow was short. 更多还原