My much better half's employers out of town have clay that tends towards the acidic due in part to nearby
native conifers. They also heat with
wood. They use their wood ash to bring their soil pH up, as D. Logan mentioned.
Wood ash appears to be only a third as effective as lime at liming the soil, so three times as much wood ash may be required to achieve the same effect. However, it is noted that commercially available wood ash is less nutritionally significant as that from woodstoves at home. In any case, determining the pH of individual batches can easily be done in a rough manner with any variety of litmus-based kit. That pH can be compared with the standard for lime in application calculations, and a precise measurement can be achieved at need.
It may take three times as much material to do the same job as lime, but if it's accumulated over time, and can be had for free, and potentially worth
carbon credits, or at least not cause carbon deficit by avoiding use of lime, there's enough going for it that it makes overwhelming sense to do, if your soil tends towards the acidic and you heat with wood, or if wood ash is a common industrial byproduct locally.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein