I recently took some pictures of the neighbor putting lime on his field. The spreader truck that applies the lime is likely equiped with a GPS system that ties back to the soil test I described in my blog post "The Soil is Alive". Both these activities trace back to the teachings of the Soil and Water Conservation Districts that were birthed as a reaction to the Dust Bowl. A view of this history is documented in the PBS series "The Dust Bowl", produced by Ken Burns that aired recently. So much of modern agriculture reaches back to the Dust Bowl/depression generation which in affect said, "we want food to be abundant and cheap and sustainable so our kids don't have to go through this."
The process is kind of dusty, since the material (lime) arrives as a very fine powder. It is fine so that it will dissolve or interact with the soil in a timely fashion.
the lime arrives in semi-trucks, is dumped in piles in the field, then scooped up and loaded into the spreader truck by an industrial payloader. This loading takes only a couple minutes. My picture is taken as the very last scoop or two of a large pile is gathered and loaded. Lime is applied in tons per acre and a semi load will be about 24 tons. So a large field can require an impressive pile of lime.
Lime is used to control the molecular acidity of the soil. The acidity of a soil determines what plants will grow well. Soil acidity is a natural response to many environmental things. Rainfall, organic matter, drainage, macro-climate, etc. all impact the soil over time. Here are some helpful links written by experts that better explain the process. Cause and Effect of Soil Acidity and When and How to Apply Lime
This is just the tip of the iceberge of knowledge that I use daily in my stewardship of the land entrusted to me by God to protect, preserve, and sustain for the future.