TY - JOUR ID - iiasa13768 UR - https://pure.iiasa.ac.at/id/eprint/13768/ IS - Part B A1 - Tian, S. A1 - Youssef, M.A. A1 - Richards, R.P. A1 - Liu, J. A1 - Baker, D.B. A1 - Liu, Y. N2 - Land use/land cover is a critical factor affecting temporal dynamics of nitrate export from watersheds. Based on a long-term(>30 years) water quality monitoring program in the Western Lake Erie area, United States, this study compared seasonal variation of nitrate export from an agricultural watershed and an urbanized watershed. A seasonality index was adapted to quantitatively characterize seasonal variation of nitrate export from the two watersheds. Results showed that monthly nitrate concentrations from the two watersheds exhibited different seasonal variation. Seasonality index of monthly nitrate loading for the agricultural watershed is approximately 3 times of that from the urbanized watershed and the difference is statistically significant (p<0.0001). Meanwhile, calculated historical seasonality indexes of monthly nitrate loading for both watersheds exhibited significant (p<0.05) decreasing trends according to the non-seasonal Mann-Kendall test. The identified differences in seasonal nitrate export from the two watersheds were mainly attributed to their distinct nitrogen sources, physical and biogeochemical settings. The declining seasonality index of monthly nitrate loading from the agricultural watershed could be partially caused by historical climate change in the study region, especially increased temperature during winter. Urbanization could be one key factor contributing to the declining seasonality index of monthly nitrate loading from the urbanized watershed. Information derived from this study have practical implications for developing proper management practices to mitigate nitrate pollution in Midwestern United States. VL - 541 TI - Different seasonality of nitrate export from an agricultural watershed and an urbanized watershed in Midwestern USA AV - none EP - 1384 Y1 - 2016/08/26/ PB - Elsevier JF - Journal of Hydrology KW - Land use; land cover; climate change; nitrate export; agricultural lands; urbanization SN - 1879-2707 SP - 1375 ER -