IDENTIFYING HIGH RISK AREAS OF N LEACHING IN THE SALT LAKE VALLEY, UTAH, USA

摘要

nitrate (NO3-N) leaching,may pose a hazard to groundwater quality.This research utilized a Geographic Information System (GIS) approach to estimate NO3-N leaching mass from urban turf areas based on a one-dimensional N leaching model and to classify the NO3-N leaching risk in the Salt Lake Valley,Utah,USA,based on soil texture.The methodology integrated a calibrated and verified Hydrus-1D N model,soil textures and urban turf areas to predict NO3-N leaching to groundwater.Thirty United States Geological Survey (USGS) residential wells were installed and sampled in 1999 for NO3- N concentration.A relationship between estimated NO3-N leaching from urban landscapes and groundwater NO3-N concentration was developed to determine the effect of soil texture and landscaped area on NO3-N leaching from urban landscapes.The GIS approach was used to estimate the NO3- N leaching risk to groundwater under efficient irrigation and fertilization scenarios and over-irrigation and overfertilization scenarios.The results showed that soil texture played a role in NO3-N leaching from urban landscapes to groundwater,and shallow groundwater was more susceptible to surface contamination compared to deep groundwater.The GIS technique identified areas where improved irrigation and fertilization management could reduce landscape NO3-N leaching significantly,resulting in fewer NO3-N leaching risk areas in the Salt Lake Valley,Utah,USA.