Field and laboratory studies were conducted to determine whether lime or alternative liming methods could ameliorate subsoil acidity in strongly acidic soils from an almond orchard near Arbuckle, CA. Lime applied to the soil surface increased pH values to 7.4 in the 15-cm depth, but little change in pH values was found deeper in the soil. Lime mixed with the soil resulted in higher pH values (6.9-7.6) in the mixed zone and below the zone of application. As pH values increased in CaCO₃ treatments, Ca became significantly higher, and Al levels decreased. Changes in soil calcium and pH levels were directly correlated, while changes in extractable soil aluminum were inversely related to changes pH values. In the field plots amended with lime, Ca and Al levels were inversely related.

Calcium acetate was an effective liming agent in laboratory batch and column studies. Potassium citrate applications were also found to be effective in increasing soil pH values. Calcium acetate was not as effective in the field as in the laboratory. Nonetheless, Ca- acetate was more effective than lime. Acetate must be metabolized before the material can act as a liming agent. Metabolism of acetate proceeded with a substantial lag period of 10-30 days in laboratory batch studies. This slow metabolism may be one reason why the field studies were less effective. In the laboratory, acetate was found in the effluent from soil columns, indicating that acetate was mobile in the soil. Acetates could have been leached out of the measurement zone before they were metabolized. Calcium acetate and potassium citrate show promise as alternative liming agents; however, techniques for applying the material most efficiently need to be worked out. Smaller, more frequent applications may be most effective. Considerable quantities of liming material are needed to correct subsoil acidity and improve soil quality.