Effects of hydrochloric acid and lime amendments on soil pH and extractable calcium and magnesium in a sandy soil

Shuman, L.M.; Boswell, F.C.; Ohki, K.; Parker, M.B.; Wilson, D.O.

Communications in Soil Science and Plant Analysis 14(6): 481-496


High water table sandy soils present special problems when establishing soil pH variables under field conditions. In order to examine the response of a coarse-textured soil to lime and HCl acid treatments, data are reported for soil pH and extractable Ca and Mg for a field experiment where Mn treatments on soybeans was the primary objective. Three treatments included HCl, control and lime. Acid (742 l/ha 3 N HCl) was added only at the beginning of the experiment but dolomitic lime treatments were added each year (2240, 2740 and 2900 kg/ha). The lime and acid were applied to the soil surface and incorporated to a depth of 10-13 cm. Soil samples were taken every 2-3 mo. at 3 depths (0-15, 15-30 and 30-45 cm) and analyzed for pH and extractable Ca and Mg. Acid treatment decreased the pH by 0.2 units below the untreated soil at the 0-30 cm depth and the effect lasted the entire 3 yr of the study. Ca values were lowered only slightly by the acid treatment. Lime additions caused steady increases in soil Ca. Mg values increased several months after each of the 1st and 2nd lime applications. Lime raised the subsoil (30-45 cm) pH after 4-6 mo. Seasonal variations in pH were very wide with the untreated soil pH varying from 6.1-6.8. The high pH level of 7.0 was not maintained for an entire season until the 3rd yr of the experiment. Soil pH as well as extractable Ca and Mg showed fluctuations that were the result of seasonal variations and soil moisture content at the time of sampling. Soil pH variables on a sandy soil should be established at least a year in advance of starting an experiment and must be closely monitored in order to maintain the desired pH levels.