Year 11 | 13 December 2019 | email@example.com
Researchers have identified a link between the diversity of crops grown in farmlands and the pollution they create in lakes and rivers.
Nitrogen from agricultural fertilizers leaches through soils to groundwater and runs off into rivers and lakes, increasing aquatic dissolved nitrate. Too much nitrate in the water can lead to prolific growth of aquatic algae, which can use up most of a water body's oxygen when they die and are decomposed, creating "dead zones" that cannot support life.
Whitney Broussard of the University of Louisiana at Lafayette and R. Eugene Turner of Louisiana State University at Baton Rouge compiled data from the past 100 years on watersheds varying in size from the Illinois Cache River basin (400 square miles) to the Mississippi River Basin (more than a million square miles). The researchers compared this watershed data with land-use practices since the early 1900s.
In areas where farming is scarce or absent, however, the authors found no perceptible change in dissolved nitrogen concentrations since the early 1900s. Broussard thinks this indicates that the impacts might be reversible if policy changes included incentives for farmers to rotate more crops, decrease their field size, increase the edges of fields and sizes of buffering zones, and incorporate more native perennial grasses into farms and in between fields.
by S. C.
16 february 2009, Food & Fun > Nature