Lime and Soil Acidity Effects on Alfalfa Growth in a Red-Yellow Podzolic Soil
1960
Moschler, W. W. | Jones, G. D. | Thomas, G. W.
Rates of ground dolomitic and calcitic limestone ranging from 0 through 16 tons per acre were applied to Tatum silt loam at the time of seeding alfalfa in the spring of 1956. Lime has proved to be indispensable to yield and longevity. Total yields for three cutting years ranged from 0.25 to 8.0 tons per acre and stand survival at the end of the third cutting year varied from 0 to 95%. A true “critical level” of calcium or magnesium in neither soil nor plant was found. Rather, increases in the rate of lime applied were accompanied by gradual increases in soil pH, exchangeable bases, and percentage base saturation. In contrast, the application of relatively small amounts of lime reduced the exchangeable aluminum content of the soil sharply, and these reductions were closely correlated with increased alfalfa yields. Yields were in better agreement with base-exchange saturation calculated from exchangeable metal cations than that calculated from metal cations plus exchangeable hydrogen. A slight and consistent increase in yield from dolomitic stone over calcitic stone was not significant. Depth of root penetration appeared not to be a factor contributing to the benefits from liming. Decrease in exchangeable aluminum in the soil and improved nitrogen metabolism are postulated as the chief favorable factors under the conditions of this experiment.
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