Boron requirement and deficiency symptoms of fenugreek (Trigonella foenum–graecum) as shown in a water culture experiment with inoculation of Rhizobium

Abstract

SummaryThis experiment was made to determine the possible reason for deficiency symptoms seen on fenugreek (Trigonella foenum-graecum) in field trials during the dry summer of 1976. Using rockwool cubes for root support, it was shown that symptoms seen in the field plants resulted from boron deficiency.The symptoms of boron deficiency in fenugreek are described and illustrated. The main symptoms were failure offloweringor fertilization, decreased apical growth, small crisped leaves in a terminal rosette and a gradual yellowing of the lower leaves. In combination with low nitrogen, the boron-deficient plants had yellow, succulent leaves at a very early stage. High calcium and high nitrogen increased the demand for boron.Inoculation with Rhizobium meliloti of plants with a low nitrogen supply was performed with success. The bacteria formed healthy, pink nodules on the roots inside the rockwool cubes.The lowest content of boron in whole plants showing boron deficiency symptoms (no pods formed) was 13 μg/g and in this respect fenugreek is very similar to lucerne (Medicago sativa), a plant known to have a high boron requirement. Fenugreek has a high tolerance of excess boron.