We use surface edge-of-field monitoring to better understand the timing and magnitude of runoff events and identify practices that reduce surface soil and nutrient losses. Surface runoff happens when rain or melting snow cannot soak into the soil. This may occur if the soil is frozen or already saturated with water. In this case, the water that cannot soak into the soil will flow downhill over the surface of the field. The edge-of-field sampling station intercepts this surface runoff. The station continuously monitors runoff volume and periodically collects water samples for analysis of soil, phosphorus, and nitrogen content. The station also has weather and soil sensors, which help us understand the conditions that prompted runoff.
Most past and current Discovery Farms surface sites monitor annual, row crop fields. These sites represent a variety of tillage, manure management, and cover crop practices. The most common crop rotations are dairy forage and cash grain. Over the years, some sites monitored perennial pastures used for grazing dairy or beef cattle, and others that represented natural or urban land cover.
