نتایج جستجو برای: point nitrogen pollution and soil erosion
تعداد نتایج: 16946384 فیلتر نتایج به سال:
Understanding spatial and temporal variations in river water quality and quantitatively evaluating the trend of changes are important in order to study and efficiently manage water resources. In this study, an analysis of Water Pollution Index (WPI), Daniel Trend Test, Cluster Analysis and Discriminant Analysis are applied as an integrated approach to quantitatively explore the spatial and temp...
Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake ar...
Background & Aims of the Study: In this research, Long-Term Hydrologic Impact Assessment model is selected for simulation of runoff and NPS pollution. The aim of this study is modeling of non-point source pollution by L-THIA model in Zayandehrood watershed in 2015. Materials & Methods: In this study, analytical survey and investigation of references in the context of libr...
Non-point source (NPS) pollution has been increasingly serious in China since the 1990s. The increases of agricultural NPS pollution in China is evaluated for the period 2000-2008 by surveying the literature on water and soil pollution from fertilizers and pesticides, and assessing the surplus nitrogen balance within provinces. The main causes for NPS pollution were excessive inputs of nitrogen...
Improper land use is one major cause of non-point source pollution. Integrated modeling would support the evaluation and optimization of land use for the non-point source pollution control. In this study, the CLUE-S (the Conversion of Land Use and its Effect at Small regional extent) and SWAT (Soil and Water Assessment Tool) models were coupled to simulate pollution loads under different land u...
This study examines the effects of land use and slope angle on runoff, soil loss and nitrogen loss from hillslopes of the Loess Plateau in China. Farmland, wasteland and four forest treatments (sea buckthornþ poplar, immature sea buckthorn, mature sea buckthorn, and immature Chinese pine) were the types of land use that were compared. The results showed that July was the critical period for run...
Soil erosion has been recognized as one of the major threats to our environment and water quality worldwide, especially in China. To mitigate nonpoint source water quality problems caused by soil erosion, best management practices (BMPs) and/or conservation programs have been adopted. Watershed models, such as the Annualized Agricultural Non-Point Source Pollutant Loading model (AnnAGNPS), have...
Soil organic carbon (SOC) is a principal component in soil quality assessment. Knowledge of SOC and total nitrogen (TN) stocks are important keys to understand the role of SOC in the global carbon cycle and, as a result, in the mitigation of global greenhouse effects. SOC and TN stocks are functions of the SOC concentration and the bulk density of the soil that are prone to changes, influe...
Soil erosion is the main pathway of nutrients to fresh water in highly erodible regions. In this study, a dynamic erosion-type nonpoint source (NPS) pollution model was proposed to investigate spatiotemporal characteristics of adsorbed NPS total nitrogen (TN) load before and after returning farmland. Results indicate that: 1) the erosion-type NPS TN load showed a significant decreasing trend si...
Soil erosion has become a serious problem in recent decades due to unhalted trends of unsustainable land use practices. Assessment of soil erosion is a prominent tool in planning and conservation of soil and water resource ecosystems. The Universal Soil Loss Equation (USLE) was applied to Nyabarongo River Catchment that drains about 8413.75 km² (33%) of the total Rwanda coverage and a small par...
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