Effects Of Simulated Nitrogen Deposition On Carbon, Nitrogen And Base Cations Leaching Of Two Soils In Three Gorges Reservoir Area

Atmospheric nitrogen deposition had greatly increased because of human activities, emissioning a large number of nitrogen compounds to atmospheric in recent decades. Nitrogen deposition could lead to soil acidification, forest degradation, water eutrophication, biodiversity loss and other serious environmental problems. This phenomenon had caught the attention of the public and the scientists, becoming one of the spotlight researchs in the ecological field.Along with the socio-economic, industrial and agricultural development, China had become the third biggest area of nitrogen deposition, following Europe and the United States. And atmospheric nitrogen deposition would continue to increase. The environmental problems of Three Gorges area had been concerned since it's construction. Large amount of researches focused on soil erosion, farmland non-point pollution, agricultural emissions of greenhouse gas, such as watershed nitrogen load. The nitrogen through atmospheric deposition into the soil or water ecosystem had not been paid attention, so the articles about the impacts of nitrogen deposition on Three Gorges soil properties had seen rarely. In this study, a soil column internal leaching experiment was conducted to investigate the effects of simulated nitrogen deposition on base cations containing K, Na, Ca, Mg and NO3-, NH4+, DOC leaching from two typical soils in Three Gorges Area. Results showed that:1. The effects of nitrogen deposition on nutrient leaching as NH4NO3.a. The Mg2+, K+ leaching loss of the Purple and Ca2+, Mg2+, K+ leaching loss of the Yellow-brown soil increased significantly because of nitrogen deposition, but the Ca2+, Na+leaching loss of the Purple and Na+leaching loss of the Yellow-brown soil had no obvious diversification.b. The NH4+ leaching concentration of the Yellow-brown soil and the NO3 leaching concentration of the PP, YP, YC increased because of nitrogen deposition, but the NH4+leaching concentration of the Purple and the NO3- leaching concentration of the PC had no obvious diversification. Apparent equilibrium value of NH4+was less than zero, while that of NO3- and inorganic nitrogen were more than zero.c. The DOC cumulative leaching loss of PP, YC increased first and then decreased with nitrogen deposition increasing, and that of YP decreased.2. The effects of nitrogen deposition on nutrient leaching as KNO3.a. The Mg2+leaching loss of the Purple and Ca2+, Mg2+, Na+, K+leaching loss of the Yellow-brown soil increased significantly because of nitrogen deposition, but the Ca2+, Na+, K+leaching loss of the Purple had no obvious diversification.b. The NH4+ leaching concentration of two soils and the NO3- leaching concentration of the PP, YC increased because of nitrogen deposition, but the NO3-leaching concentration of the PC, YP had no significant diversification. Apparent equilibrium value of NH4+ was less than zero, while that of NO3- and inorganic nitrogen were more than zero.c. The DOC cumulative leaching loss of YP was largest in tested soils.