Growth and magnesium uptake of tall fescue clones with varying root diameters

Abstract A cool season perennial grass with a root system capable of penetrating hardpans and which can accumulate adequate Mg to prevent deficiencies in forage is needed in the Coastal Plain region. A greenhouse experiment was conducted to determine the effects of magnesium (Mg) concentration in nutrient solution and root diameter on Mg uptake and growth of tall fescue (Festuca arundinacea Schreb.). Propagules of two fescue clones with large root diameter (LDR >1 mm), two clones with small root diameter (SDR <0.8 mm), and a single clone from ‘Kentucky 31’ (Ky‐31) were transferred into 12‐liter tanks containing Mg concentrations of 3, 21, 42, 125, 250, and 500 μM as MgSO4 and grown for 39 or 70 days. Leaf Mg concentration was increased linearly with Mg solution concentration in LDR clones for a 39‐day growth period (Harvest 1), but increased according to a cubic equation in the SDR clones and the Ky‐31. Predicted leaf Mg concentration as a function of solution Mg followed a cubic equation for a 70‐day gro...