The effect of sulfur and sulfuric acid upon the development of soil acidity at different depths
1936
Fraps, G.S. | Fudge, J.F.
Different quantities of sulfuric acid and sulfur were added to the surface 5 inches of a Lufkin fine sandy loam in 18-inch tiles, and the pH values of samples of the soils from different depths were determined at intervals over a 5-year period. Maximum acidity of the surface soil developed within 10 weeks and that of the next 2 or 3 inches within 4 months after treatment. Acidity of all treated soils then slowly decreased. Penetration of acidity in excess of 2 or 3 inches occurred only in series in which the surface soil became so acid that no plant growth could occur. The presence of free sulfuric acid and soluble salts in the soil solution was evident from the pH values secured. Increases in exchangeable hydrogen at the end of 5 years were equivalent to an average of about 60% of the acid added. The remainder of the acid must have reacted with non-exchange compounds in the soil, including bases made available by weathering. Single applications of acid to the surface soil is not a practical method for acidifying the subsoil for the control of plant diseases.
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