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The fate of field-applied nutrients warrants careful consideration regarding agricultural production. Fertilizer-derived nutrients can be subjected to substantial losses through surface runoff events in certain climactic conditions. Although research of nitrogen (N) and phosphorus (P) in surface runoff has been highly documented, the studies of secondary nutrients such as sulfur (as sulfate, SO42-) surface runoff have not been as extensive. In May 2022, the Arkansas Discovery Farms Program (ADF) initiated a study measuring sulfate-sulfur (SO4-S) concentrations and land area losses collected in edge-of-field runoff samples from 8 ADF research sites. The ADF locations are generally categorized as 6 row crop and 2 forage production systems. Mean SO4-S concentrations in runoff ranged from 2.1 milligrams per liter (mg/L) in Stuttgart (rice and soybeans) to 18.9 mg/L in Dumas (cotton), while sulfate losses ranged from 0.1 pounds per acre (lb/ac) at Wedington and Stuttgart to 1.7 lb/ac in Light. Dumas, Light, and Elkins farms had significantly greater SO4-S concentrations in edge-of-field runoff samples than Delaplaine, Newport, Stuttgart, and Wedington. Interpreting SO4-S losses by mass losses per unit area (concentration*runoff volume/land area), Light had significantly greater losses than Newport, Delaplaine, Stuttgart, and Wedington. In addition, variations in significant differences were observed for the other ADF sites in terms of SO4-S concentrations and land area runoff losses. These observations highlight diverse production and nutrient management strategies among the 8 ADF research locations. Statistical analysis of total runoff per acre showed Newport being significantly higher than Cherry Valley, Dumas, Elkins, and Wedington. Complementary soil sampling events and calculations of SO4-S losses will supplement awareness of SO4-S runoff and soil-based dynamics. [ABSTRACT FROM AUTHOR]

Environmental concerns regarding manure management in dairy production are typically confined to nutrients such as nitrogen (N) and phosphorus (P), while potassium (K) is a nutrient less likely to be considered. The Haak dairy farm employs a paddock arrangement with rotational grazing, seasonal crop production, and the milking of approximately 160 cows. Fields dedicated to grazing receive applications of dairy manure. This manure comes from the milking center, where it is then mixed with sawdust and deposited in an open-air containment area awaiting field application. The purpose of this study was to evaluate soil-test potassium (STK) levels from designated sites across the dairy's fields by grid-soil sampling in 2017, 2018, and 2020. A total of 100 soil samples were collected each year, 50 at the 0--4 in. depth and 50 at the 4--8 in. depth along 10 sampling transects. Grid-soil sampling techniques remained identical for all 3 years. Analysis of STK indicated that there was a significant rise in STK at the 0--4 in. sampling depth from 2017 to 2018 and 2020, while STK for 2018 and 2020 was not significantly different. Analysis of the 4--8 in. samples exhibited significant STK increases among the three experimental years. The significant increase in STK between 2018 and 2020 was recognized as the result of intensification in grazing and manure accumulation due to an expansion of dairy cattle from 2017 to 2018 (80 to 160 head). [ABSTRACT FROM AUTHOR]

Achieving agronomic production goals for pasture-raised beef requires knowledge of the soil fertility status (i.e., N, P, and K) for optimal forage growth. Recent interest has emphasized using soil health assessments as a way for land managers and conservation agencies to measure the functional capacity of managed soil resources to sustain crop production. The Haney Soil Health Test is one method that has garnered much attention since being developed in 2006. However, data comparing the H3A (Haney, Haney, Hossner, and Arnold) extractant used in the Haney Soil Health Test to conventional soil test methods is limited. The main objective of this study was to evaluate the correlation between soil test phosphorus (P) and potassium (K) extracted using the H3A and Mehlich-3 (M3) extractants. Biennial soil samples were collected from a rotational-grazing pasture from 2013 to 2021 and analyzed using both M3 and H3A extractants. Mehlich-3 and H3A extractable P (r = 0.86) and K (r = 0.94) were strongly and positively correlated. Mehlich 3 extracted 4.4 times more P and 3.7 times more K than H3A. The results indicate that more work is needed to determine how soil health indicators included in the Haney Soil Health Test, such as soil respiration and water-extractable N and P, might help inform management decisions while safeguarding Arkansas producers' profits and production goals. [ABSTRACT FROM AUTHOR]

Manure management is critical for animal farming operations, particularly dairy production. The Haak dairy farm utilizes a paddock system that includes rotational grazing, the growing of crops such as rye (Secale cereal L.) and wheat (Triticum aestivum L.), and milks up to 160 cows. Grazing areas at the farm are periodically treated with dairy manure. The manure originates from the dairy’s milking parlor, where it is then combined with sawdust and stored in an open-air facility prior to field application. The objective of this research was to assess soil-test phosphorus (STP) levels from selected locations throughout the dairy farm by grid-soil sampling in 2017, 2018, and 2020. A total of 100 soil samples were collected each year, 50 at the 0- to 4-in. depth and 50 at the 4- to 8-in. depth along 10 sampling transects. The grid-soil points and sampling transects remained the same for all 3 years. Analysis of STP showed that there was a significant STP increase for the 0-to 4-in. sampling depth from 2017 to 2018 and 2020, while 2018 and 2020 values were not significantly different. Analysis of the 4- to 8-in. samples showed a significant increase in STP among the three sampling years. The trend of increasing STP in 2018 and 2020 was attributed to an increase in grazing and manure deposition due to a doubling of the number of dairy cattle between 2017 and 2018 (80 to 160 head). [ABSTRACT FROM AUTHOR]

Soluble K (SK) loss in surface runoff water is associated with no known environmental consequences. Few studies have evaluated and reported SK in runoff from agricultural fields. This report summarizes the findings from a fieldscale investigation of 3 farms in Northwest Arkansas from 2019 to 2021. Storm runoff and grid soil samples were collected from 7 fields used for either poultry, row-crop, or forage production to characterize annual SK losses and spatial distribution of soil-test K. Since 2019, cumulative annual SK in runoff ranged from 0.1 lb K2O/ac for a pasture to 94.6 lb K2O/ac from a broiler house production area. Results showed that for a mixed-grass warm-season hayfield (Morrow-3) and a field cropped to corn (Zea mays L.) and soybean (Glycine max Merr.; Moore-1), the amount of SK recovered in runoff was equivalent to 8.1% and 13.7%, respectively, of the K applied in poultry litter to each field during the study period. While for a rotationally grazed pasture (Morrow-2), recoverable SK in runoff accounted for about 1.3% of the K that was applied as litter. The findings of this study show that K loss in runoff can be significant and should be considered in field K budgets. [ABSTRACT FROM AUTHOR]

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, SO42-) 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]