Monday, November 13, 2006 - 2:15 PM

Liming Stockpiled Tall Fescue Changed Macro- and Micronutrient Concentrations.

Elizabeth Hamilton, Dale Blevins, and Randall Miles. University of Missouri, 1-87 Agriculture Bldg, 1-31 Agriculture Bldg, Columbia, MO 65211, United States of America

Many soils in Missouri are inherently acidic and possess little available phosphorus (P).  Fertilization with P increased concentrations of calcium (Ca), magnesium (Mg), potassium (K), and P in the leaves of stockpiled tall fescue, Festuca arundinacae, (McClain and Blevins, unpublished data), the major forage in Missouri.  However, little is known about the effects of lime, an amendment that adds Ca or both Ca and Mg while increasing soil pH, on the macronutrient and micronutrient composition of stockpiled tall fescue.  A site was chosen at the Universtiy of Missouri Southwest Center on a Gerald silt loam, a fine, mixed, active, mesic Aeric Fragiaqualf.  Calcitic and dolomitic limestone was applied at 0, 1/2x, 1x and 2x the recommended soil test rate by the Woodruff Buffer method.  Tall fescue leaves were harvested several times annually, dried, ground, digested, and nutrient concentrations were analyzed by ICP-OES. 
Leaf macronutrient concentrations were effected differently by lime applications; P concentrations were relatively unaltered by lime, but K concentrations decreased in limed plots while leaf Ca increased.  Additionally, leaf Mg concentrations decreased in calcitic treatments but increased with the application of dolomitic lime.  As a result of the changes in leaf K, Mg, and Ca, the tetany ratio (meq K/ meq Ca + meq Mg) of limed plots decreased.  Leaf micronutrient concentrations were also altered.  Leaf manganese (Mn) and molybdenum (Mo) concentrations decreased and leaf boron (B) increased within three months of lime applications.  Lime had little influence on leaf aluminum (Al), iron (Fe), and copper (Cu) concentrations.  Lime’s effects on the macro- and micronutrient concentration of stockpiled tall fescue leaves may improve the health of cattle grazing stockpiled tall fescue pastures.