Post-harvest lime applications are the best, according to Tim Stelter, Federated agronomist at the Osceola location. "As soon as you get the crop off, before you till it, apply lime," he said, adding that "you'll get a better spread pattern because [the field] is nice and smooth."
Fall lime applications are better on the equipment and on the people who do the applications (because fall isn't as busy). Spring road restrictions also inhibit timely lime applications.
Fall lime applications are better for the soil because the lime has time to react in the soil - which is especially important for fields going to beans next year. Alfalfa needs even more time, Stelter noted, so Fall 2017 lime application will be great for Fall 2018 alfalfa seeding.
Of course, Stelter said, "Get soil samples done [before applying lime]." (See article below.)
Lime also needs to be applied while temperatures are above 50 to enable the chemical reaction that makes lime beneficial. "Years of fertilizer can take its toll and the pH decreases (which ties up nutrients)," said Stelter, "so you need to add lime to get pH to the right levels (6.8 is neutral; alfalfa needs a minimum of 6.5, corn is ok at 6.5, and anything much below 6 causes trouble with soybeans)." See chart.
Talk to your Federated Agronomist for more information on fall lime application.