By Ryan McGeeney
For more that 100 years, Arkansas Agricultural Experiment Station and the Cooperative Extension Service have brought the dual aspects of the “research and extension” concept together for the benefit of Arkansas producers, making science-based, unbiased recommendations for the selection of crop seed, fertilizer, pesticides and more.
Today, one of the University of Arkansas System Division of Agriculture’s primary tasks is to continually refine those recommendations by putting them to the test in real-world situations across the state.
Brad Runsick, agricultural agent with the Fulton County Cooperative Extension Service, is one of many county agents throughout Arkansas currently demonstrating and testing some of those recommendations, day in, day out. He is now about one year into a three-year demonstration trial designed to test the Division of Agriculture’s recommendations for the use of agricultural lime to neutralize acidity and raise the pH level in soil.
“The use of limestone is one of our best tools in Arkansas agriculture to get the soil to where we need it to be for specific crops,” Runsick said. “Soil pH is a big factor in soil fertility, and is a determining factor when it comes to production yields. Lime neutralizes the acidity in soil and raises the pH level.”
On a private farm in Fulton County, Runsick marked off 45 plots, each measuring about five feet by 25 feet, Runsick began putting the Division of Agriculture’s lime application rate recommendations to the test in January 2016. After taking an initial sample of soil from each plot for analysis, Runsick applied differing rates of both agricultural limestone and pelletized lime, a product often marketed as a lower-cost alternative to raw agricultural lime, to the plots.
“We’re monitoring the effect of the lime application on the soil pHover three years, resampling it at different points in time,” Runsick said.
Runsick said that part of this particular demonstration was to test rates of pelletized lime that are often recommended by dealers against the higher rates of agricultural lime typically recommended by the Division of Agriculture.
“There are claims that a producer can use very low rates of pelletized lime in order to achieve the same effect as our recommended rates of agricultural lime,” Runsick said. “If we say you need, for example, two tons of ag lime to fix your soil pH, there may be some who claim that you can use 400-500 lbs. of pelletized lime to achieve the same effect. I don’t think the data from past research or this project agrees with that.
“This project examines those application rates. The plots that receive ag lime are getting one, two, three and four tons per acre. The plots getting pelletized lime are receiving it at rates that are often being recommended and sold to producers by dealers — 100, 500, 1000 lbs. per acre,” he said. The cost per acre of each of these rates has also been noted.
“We’re not trying to take a position on any particular product,” Runsick said. “Not all lime is created the same. Even the quality, and therefore neutralizing value, of ag lime varies greatly across the state.
“It’s just important for producers to know what the neutralizing value is, how it relates to their soil test recommendations and whether or not an application is cost effective,” he said. “We just want producers to look at these kinds of demonstration results and use them as they will.”
Runsick’s demonstration is just one of many going on throughout the state at any given time. He said that although it’s hard to quantify the impact of any given demonstration study, the fact that the Division of Agriculture’s recommendations are generally reinforced through the efforts helps bolster producer confidence, and ultimately helps them farm in a more cost-effective manner, a key to success in one of the nation’s most agriculturally-dominated state economies.
“Improving oil fertility isn’t a one-time thing you do, and it’s done — it’s more of a gradual, progressive process,” Runsick said. “And this project is the same way. It’s going to take a while for things to materialize and the end result to be seen.
“Local farmers like to see local results,” he said. “People want to see things that work in their county, and under their conditions.”