Requirements and Tolerance to Elements by Alfalfa1

Abstract

AbstractAlfalfa (Medicago sativa L., ‘DuPuits’, F.C. 40247) is a cultivar of the Flemish type selected on a clay‐loam soil in northern France. It matures early and grows rapidly after each cutting, but little is known about its nutrient requirements. The objective of this study was to determine the nutrient requirements or tolerance of DuPuits alfalfa for specific elements. It was subjected to Fe, Zn, and Cu stresses, and to Mn and Al toxiclties by growing it on seven soils known to produce these deficiency or toxicity symptoms in other crops. DuPuits alfalfa developed severe Zn deficiency symptoms on most alkaline soils, Al toxicity symptoms on acid Bladen soil, and Mn toxicity symptoms on acid Richland soil. When lime was added to the two acid soils, the plants developed Cu deficiency symptoms on Bladen (pH 5.3) and deficiency symptoms on Richland (pH 7.0). The deficiency symptoms were corrected by adding Cu and B to these soils, respectively. DuPuits alfalfa absorbed and transported Fe from the alkaline soils and it never developed Fe deficiency symptoms.