Nature World: Changes in agriculture affect river flow rates in both rainy and dry times, according to two University of Iowa researchers. While it may seem obvious that river flow rates in the Midwest can change depending on how heavy or light rainfall is, what's not so clear is how changes in land use can impact these river flows. "We wanted to know what the relative impacts of precipitation and agricultural practices played in shaping the discharge record that we see today," lead author Gabriele Villarini...