I like to keep my pH over 6.5, so yes, you could use a little lime on your 5.x pH's.

This website has a LOT of god liming information: https://aglime.org

These were found there....

"What About High-pH Soils?

Some farmers, especially in the northern Corn Belt, have to deal with high soil pH, typically from 7.2 to 8.1. “High pH can result from over application of poultry layer manure or limestone,” says Farm Journal Field Agronomist Ken Ferrie. “But typically, it is just a characteristic of certain soil types.”

In those calcareous soils, if you dig below the 4″ to 5″ tillage zone, you will usually find shells or pieces of shells. That indicates aquatic creatures once lived in the area when it was a swamp or lakebed.

Soil organisms don’t like high pH any better than low pH. But, in high-pH soils, rather than becoming toxic, nutrients, such as iron and aluminum, become deficient, causing iron and aluminum chlorosis. Phosphorus is another nutrient that becomes deficient.

If you get high pH results from over liming, simply quit liming for awhile. But, there isn’t much you can do to change a calcareous soil, Ferrie says. “Your best bet is to plant varieties bred to resist iron chlorosis,” he says. “Be careful about applying urea on the surface; it could be lost to volatilization. Band your phosphorus to keep it from becoming tied up. And, manage your herbicides because there may be carryover.”"

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pH and Yiekl potential01192019 (full).jpg (83KB - 64 downloads)