Lime Requirement Methods for Cold-Region Soils1

Abstract

Virgin acid soils collected in Alaska between 58 and 66° N Lat. were equilibrated with increasing increments of CaCO3 to determine quantities of lime required to neutralize the acidity. Barley seedlings were grown to minimize accumulation of salts during the incubation period. Quantities required per 1.0 unit pH increase to pH 6.5 varied from 1.2 to 7.7 metric tons/ha. Calcium hydroxide provided the best predictive indicator of needed lime (r = 0.946), but due to the slowness of the test, other procedures were considered. In comparison with calcium carbonate and moist incubation, the Woodruff procedure, the Shoemaker, McLean, and Pratt (SMP) procedure, the BaCl2-triethanolamine procedure, and the base saturation procedure resulted in correlation coefficients of 0.867, 0.859, 0.841, and 0.806, respectively. The Woodruff and SMP predicted lime requirements were highly correlated, r = 0.993. The Woodruff procedure recommended greater lime quantities at a low lime requirement, and the SMP procedure recommended greater quantities at a high lime requirement. At high requirements, however, the SMP procedure as originally calibrated overestimated lime needs by a factor of 2 in these soils formed under cryic temperature regimes. Most of the virgin soils that were collected from southern and southeastern Alaska and that had agricultural potential had natural pH's below 5.5; those soils sampled in western Alaska, especially alluvial soils, had natural pH's above 6.5 and did not require lime additions.