Nonpointsource nitrogen and phosphorus loadings

Authors: Bo Zhu Zhenhua Wang Tao Wang Zhixin Dong

Publish Date: 2012/01/25

Volume: 9, Issue: 1, Pages: 10-15

PDF Link

Abstract

Nonpointsource pollution has become a major threat to the water quality of the Three Gorges Reservoir TGR however nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring A representative small watershed in the central part of the TGR area was selected to monitor the loss of nitrogen N and phosphorous P continuously along with the runoff from 2007 through 2009 to understand the exact sources and loadings Results show that the nonpointsource nitrogen and phosphorus comes mainly from the storm runoff from residential areas citrus orchards and sloping croplands which contributes up to 76 of the loadings in this watershed Thus a crucial measure for controlling nonpointsource pollution is to intercept storm runoff from the three sources Paddy fields provide a sink for nonpointsource N and P by intercepting the runoff and sediment along with their different forms of nitrogen and phosphorus The N and P removal efficiency by paddy fields from residential areas is within the range of 56 to 98 Paddy fields are an important landuse option for reducing the nonpointsource loading of N and P in the TGR area

Keywords: