Author(s): Zhiguo He; Haoxuan Weng; Miaohua Mao; Qihua Ran
Linked Author(s): Zhiguo He
Keywords: Pollutant transport; Rainfall-runoff; Erosion; Sediment transport; Sorption; Desorption; Nitrogen
Abstract: Pollutant from surface applied agricultural chemicals and pesticides is one of the major sources of contamination in water bodies. The transport of pollutant within a watershed is highly influenced by the rainfall-runoff and the associated upland erosion and sediment transport processes since most of pollutant can be dissolved in water and also attached to the soil particles. In this study, laboratory experiments using a soil flume adjustable to different slopes with a rainfall simulator were carried out to investigate the impacts of upland erosion and sediment transport on pollutant loads and transport. The soil used in the experiment was the silty sand collected from China’s Loess Plateau. Ammonium bicarbonate was applied on the soil surface before the rainfall and considered as a pollutant source. Runoff discharge, soil loss, and ammonia-nitrogen and nitrate-nitrogen concentrations in both runoff and sediment were then measured. The results show that the peak of the ammonia-nitrogen concentration in runoff appears at the initial stage of the overland flow generation, and then its value decreases quickly and approaches to the steady state. The ammonia-nitrogen transported by the soil loss also makes contributions to the total nitrogen loss. Its amount mainly depends on the transport rate of soil. The results also show that the dissolved ammonia-nitrogen is dominant in overland flow due to the strong aqueous solution of Ammonium bicarbonate during the first storm right after its application.
Year: 2013