  Reducing the size of the hypoxic zone in the Gulf of Mexico has proven to be
a challenging task. A variety of mitigation options have been proposed, each
likely to produce markedly different patterns of mitigation with widely varying
consequences for the economy. The general consensus is that no single measure
alone is sufficient to achieve the EPA Task Force goal for reducing the Gulf
hypoxic zone and it appears that a combination of management practices must be
employed. However, absent a highly resolved, multi-scale framework for
assessing these policy combinations, it has been unclear what pattern of
mitigation is likely to emerge from different policies and what the
consequences would be for local, regional and national land use, food prices
and farm returns. We address this research gap by utilizing a novel multi-scale
framework for evaluating alternative N loss management policies in the
Mississippi River basin. This combines fine-scale agro-ecosystem responses with
an economic model capturing domestic and international market and price
linkages. We find that wetland restoration combined with improved N use
efficiency, along with a leaching tax could reduce the Mississippi River N load
by 30-53\% while only modestly increasing corn prices. This study underscores
the value of fine-resolution analysis and the potential of combined economic
and ecological instruments in tackling nonpoint source nitrate pollution.
