Chen Cheng-Long, Gao Ming, Mu Zhi-Jian, Ni Jiu-Pai, Qi Le
College of Resources and Environment, Southwest University, Chongqing 400715, China.
Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, China.
Huan Jing Ke Xue. 2017 Aug 8;38(8):3254-3263. doi: 10.13227/j.hjkx.201701137.
Long-term field monitoring data was analyzed regarding the characteristics of nitrogen and phosphorus in the soil and shallow groundwater of different land use types in a typical small watershed of the Three Gorges Reservoir area. Furthermore, the relationships among soil nitrogen and phosphorus contents, concentrations of nitrogen and phosphorus in shallow groundwater, and slope surface runoff were analyzed. The results showed that the average contents of TN and NO-N in terrace soil were significantly higher than those in sloping upland soil (< 0.05), for which the average content of paddy terrace was highest (1.49 g·kg). The average contents of TP in the soil of sloping upland and mulberry-sloping upland were significantly higher than those in the soil of other land types. The average content of NO-N in the soil of dryland terrace was highest of all land use types and its discrete degree was also largest. The slope land use type had greater impact on the concentrations of TN and NO-N in shallow groundwater, but it had little influence on TP concentration. In addition, the shallow groundwater TN concentration and NO-N concentration had significant positive correlation, and the average contribution rate of NO-N to TN in five wells ranged from 67.82% to 78.51%. The monthly average concentration of TN and NO-N in shallow groundwater changed little, only showing a significant upward trend after the fertilization stage of the two crops in spring and autumn. The average contents of TN and NO-N in the slope soil were significantly correlated with the TN and NO-N concentrations in the shallow groundwater, but there was no significant correlation between the TN and NO-N concentrations in the surface runoff. When the slope surface runoff TP concentration was>0.1 mg·L, the average content of TP had a significant linear correlation with it. There was a significant power function relationship between the concentrations of TN and NO-N in the surface runoff and concentrations of TN and NO-N in the shallow groundwater, with higher correlation of NO-N concentrations between surface runoff and shallow groundwater.
分析了三峡库区典型小流域不同土地利用类型土壤及浅层地下水中氮、磷特征的长期野外监测数据。此外，分析了土壤氮磷含量、浅层地下水氮磷浓度与坡面径流之间的关系。结果表明，梯田土壤中总氮（TN）和硝态氮（NO₃-N）的平均含量显著高于坡耕地土壤（P<0.05），其中水田梯田平均含量最高（1.49 g·kg）。坡耕地和桑坡地土壤中总磷（TP）的平均含量显著高于其他土地类型土壤。旱地梯田土壤中NO₃-N的平均含量在所有土地利用类型中最高，且离散程度也最大。坡地土地利用类型对浅层地下水中TN和NO₃-N的浓度影响较大，但对TP浓度影响较小。此外，浅层地下水TN浓度与NO₃-N浓度呈显著正相关，五口井中NO₃-N对TN的平均贡献率在67.82%至78.51%之间。浅层地下水TN和NO₃-N的月平均浓度变化较小，仅在春秋两季两种作物施肥期后呈显著上升趋势。坡地土壤中TN和NO₃-N的平均含量与浅层地下水中TN和NO₃-N的浓度显著相关，但地表径流中TN和NO₃-N的浓度之间无显著相关性。当坡面径流TP浓度>0.1 mg·L时，TP的平均含量与之呈显著线性相关。地表径流中TN和NO₃-N的浓度与浅层地下水中TN和NO₃-N的浓度之间存在显著的幂函数关系，地表径流与浅层地下水之间NO₃-N浓度的相关性较高。
