Sulfate Loss in Runoff from Arkansas Discovery Farms Research Sites.

Nutrient management is an essential function of successful agricultural production. Field-applied nutrient loss via surface runoff poses challenges to Arkansas farmers and producers. While the majority of research regarding nutrient runoff loss has mainly dealt with nitrogen (N) and phosphorus (P), runoff loss of nutrients such as sulfur (as sulfate, SO₄^2-) are studied to a lesser extent. In May 2022, the Arkansas Discovery Farms Program (ADF) began research quantifying the concentrations and land area losses of sulfate-sulfur (SO₄-S) collected in edge-of-field runoff samples from 8 ADF locations. These ADF sites are composed of 6 row crop and 2 forage operations. Statistical analysis of preliminary data comparing collected edge-of-field runoff samples by ADF location showed that the row crop systems in Light and Dumas, Arkansas had significantly higher SO₄-S concentrations in edge-of-field runoff samples than all other ADF sites. In terms of SO₄-S losses by land area, Newport, Dumas, Light, and Elkins had significantly higher losses than the other ADF sites. The remaining ADF locations varied in their respective significant differences as well, underscoring the effect of each individual farm's approaches to crop and nutrient management. Statistical analysis of total runoff per acre showed Newport being significantly higher than all other ADF locations. The addition of non-growing season edge-of-field runoff data generated from annual soil sampling events and evaluations of field-applied SO₄-S fertilizer efficiency will provide a clearer view of SO₄-S runoff aspects and its activity in the soil under a variety of cropping systems. [ABSTRACT FROM AUTHOR]