Runoff Water Quality from Corn Production: A Summary of Results from the Arkansas Discovery Program.

The overall goal of the Arkansas Discovery Farms program is to assess the need for and effectiveness of on-farm conservation practices, document nutrient and sediment loss reductions, soil health and water conservation in support of nutrient management planning and sound environmental farm stewardship. Using state-of-the-art, edge-of-field runoff monitoring on several commercial, row crop farms in Eastern Arkansas, 268 water samples were collected from 15 different fields during 2013 to 2019 representing 20 site years. Median values across all sites and years for nitrate + nitrite-N (NO3 -), total nitrogen (TN), soluble reactive phosphorus (SRP), and total phosphorus (TP) were 0.45, 1.57, 0.13, and 0.53 parts per million (ppm), respectively. These results indicate relatively low concentrations that are similar to median values from streams in agricultural watersheds across the country. This implies that corn producers that cooperated in this study closely and consistently matched fertilizer needs to crop needs, so that there were only small amounts of fertilizer nutrients (P and N) available to be transported via runoff from the field following application. Overall, Discovery Farm studies have indicated that less than 5% of N and P applied as fertilizer leaves the field in surface runoff. [ABSTRACT FROM AUTHOR]

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