EFFECTS OF LIME ON EXTRACTABLE ALUMINUM AND OTHER SOIL PROPERTIES AND ON BARLEY AND ALFALFA GROWN IN POT TESTS

Abstract

Liming of six acid soil samples in an incubation experiment with rates to raise the soil pH to 6.0 or above eliminated Al soluble in 0.01 M CaCl 2 , reduced soluble Mn and Zn, increased NO 3 -N markedly, and at the highest pH increased the amounts of NaHCO 3 -soluble P in some of the soils. In corresponding pot experiments, liming increased the yield of alfalfa and in three of the soils the yield of barley also. Liming reduced the concentrations of the metals in the plants and at the highest pH tended to increase the P content of the plants. Liming to a pH of about 5.3 eliminated or greatly reduced soluble Al and the soils were base saturated as measured by the replacement of Al, Ca, and Mg by a neutral salt. There was some evidence that liming to reduce soluble Al and possibly Mn was beneficial for plant growth. Gypsum increased the concentrations of Al, Mn, and Zn in 0.01 M CaCl 2 extracts of the soils whereas phosphate reduced them. The changes in the Mn content of the plants following these treatments were in agreement with the amounts of Mn in the CaCl 2 extracts.