Soil Reactions at Various Depths as Influenced by Time Since Application and Amounts of Limestone

Abstract

AbstractLimestone at 2, 4, 8, and 16 tons on the surface of grassland in 1930, increased the pH to depths of 6, 12, 15, and 24 inches, respectively, by 1939. By 1953, the pH had increased to depths of 8, 10, 24, and 30 inches, respectively. The soil was a fine sandy loam, with 50% clay plus silt and had not been tilled since about 1895.The results 2 years after adding the limestone show that even the unusually high rates of limestone had not affected the pH values of the soil nearly as deeply as had much less limestone after longer lapses of time.The surface inch of soil had increased in acidity again 5 years after liming in the 1‐, 2‐, and 4‐ton plots, and 9 years after liming in the 8‐ and 16‐ton plots.The lime requirement and exchangeable base determinations corroborate the pH data.The results clearly show that it is possible to decrease the acidity of soils to depths far below where liming materials are actually placed. For a given soil and climate, rates and final depths of such penetrative effects depend on the amount of lime applied and on the lapse of time.