Update:
Over the recent past, there has been increased interest across natural resource agencies, agriculture producers, and the scientific community to examine the efficacy of soil and water conservation practices as they relate to nutrient loss (particularly nitrogen and phosphorus), soil erosion, soil health, and stream ecological integrity.
Historically, prescribed soil and water conservation practices have focused on slowing the movement of soil and nutrients after they have become entrained and moving off-site. There is growing interest in technologies that keep soil and nutrients in place where they can best be utilized by crops and enhance soil health. One such practice is the use of fall cover crops that are planted during those portions of the year when conventional crops (corn and soybeans mostly) are not in production.
The two watersheds selected for this study are both tributaries of the Eel River in northern Indiana. They include the upper portions of Beargrass Creek (treatment watershed) and the upper portion of Pawpaw Creek (reference watershed) in Wabash County. The streams within each watershed are monitored with time-integrated discrete ISCO 6712 water samplers during the months of May and June. During all other months (July-April), the first rain event that increases stream discharge will be analyzed unless it is too below freezing.
The results section of this report consists of tables and graphs (see uploaded PDF report) that represent data summaries from 2014-2018. The interpretation of this data proves to be more of a challenge at this temporal and spatial scale, but new patterns and trends have started to emerge. Five years of data is less than a radar blip in nature time, but it is a start and provides a solid scientific approach to illuminate responses to new and innovative management approaches at a 12 digit-HUC and a basin dominated by row crop agriculture and over 400,000 hogs. Over the period of our partnership we have observed a very wet year with over 50 inches of rain in 2017 and 2018 with only about 33 inches of rain. We documented a steady decline in the median concentration of Nitrate-Nitrite, but this is a bit deceiving because these declines are more associated the chemistry of Nitrate-Nitrite in high flow conditions.
We continue to see large movement of sediment and phosphorus across all years. Phosphorus and sediment are chemically tied together and closely associated with rain events. We saw phosphorus loads exceeding target value of 0.076 mg/L more than 90% of the time.
View uploaded report
final results will be posted