Monitoring water quality variation at the outlet of agricultural
basin is a basic way to understand diffuse N pollution discharging
to the water bodies. The influences of land use, agricultural
practice, and climate change on diffuse N yield have been observed
(Ouyang et al., 2010; Praskievicz and Chang, 2009). However,
regular monitoring cannot assess high temporal resolution loading
variance over a long term period or basin larger than one million
hectare (Mbonimpa et al., 2014). To better characterize the
temporal and spatial variations of diffuse N pollution of basin,
the physically based models with geographical information system
and remote sensing data have been employed in recent decades
(Birkinshaw and Ewen, 2000). The temporal-spatial pattern of
pollution loading can be simulated by models using different
approaches that can also determine critical source areas (Trevisan
et al., 2010).