Effect of soil nitrate on the growth and nodulation of winter crop legumes

Abstract

The relative effect of increasing external nitrate supply on the nodulation of 3 winter crop legumes was examined in a controlled environment experiment. Lupin (Lupinus angustifolius cvv. Chittick, Wandoo), chickpea (Cicer arietinum cvv. Tyson, Amethyst) and field pea (Pisum sativum cvv. Maitland, Dundale) were grown at 2 nitrate (NO-3) concentrations of 2 and 8 mmol/L for 40 days.Shoot and root growth were not affected by NO-3 concentration. Increased NO-3 concentration significantly (P<0.05) reduced nodule number and nodule weight in all species. The inhibition of nodulation by increased NO-3 was greatest in peas, followed by chickpeas, and least in lupins.