Notre Dame Department of Biological Sciences
At Notre Dame, a team of professors, students, and scientists are working directly with farmers to study and implement agricultural practices to keep nutrients on fields, where farmers need them. Professor Jennifer Tank is a stream ecologist who is studying the movement of nutrient runoff from Indiana’s farmland into the local streams, rivers, and ultimately the Great Lakes and Gulf of Mexico. In fact, the nutrients these watersheds are carrying are at least partially responsible for the “Dead Zone” or hypoxic zone in the Gulf of Mexico where algal blooms have created low oxygen environments that can kill fish and other types of marine life.
The Tank laboratory is committed to using stream and water chemistry analysis of agricultural drainage streams to test two potential solutions to this runoff problem: cover crops and two-stage ditches. Both solutions to nutrient pollution are potentially both environmentally effective end economically beneficial for the farmers.
Cover crops like ryegrass can be planted after cash crop harvest to improve soil health by reducing soil erosion, decreasing soil compaction, increasing soil organic matter, and suppressing weed growth. Increased uptake by cover crops of residual soil nitrogen and phosphorus during the winter and spring, when fields are normally bare, can reduce nutrient concentrations in the soil and potentially reduces leaching to streams.
Two-stage ditches are another conservation technique that the tank lab studies. These ditches are an in-stream practice that transforms conventionally-managed, trapezoidal ditches into stable systems by constructing “mini floodplains” within the stream. These floodplains improve bank stability while reducing sediment and nutrient export. Two-stage ditches work by slowing down the water in the streams and allowing particles to be deposited in the stream sediment that would otherwise have been washed downstream.
In order to study both the two stage ditch and winter cover crops, the Tank Laboratory in Notre Dame has created a demonstration watershed in order to “saturate” a watershed with conservation techniques. This demonstration watershed, which has about 60% of the cropland using winter cover crops and irrigated by a two-stage ditch, is sampled twice a week by undergraduate and graduate students. A large-scale, environmentally relevant experiment like this could give scientists and the agricultural sector vital information about effective conservation practices to reduce nutrient loss and keep nutrients on field, where farmers need them.
Working in the Tank Laboratory allowed me to experience working with graduate students, and will really help me decide what to do after I graduate from Colby. I learned that I love both field and laboratory work, and that I may want to pursue a career or degree in the future that embraces one or both of those parts of science. I also learned a lot about the importance of producers (farmers) in conservation, and that communicating conservation and science to the people who are working directly in the fields is absolutely vital.