Nitrogen fixation potential of some Leguminous trees

The nitrogen fixation potential of three important species of western-Himalayas viz., Acacia catechu, Albizia chinensis and Alnus nitida grown in nursery revealed highest number of nodules per plant in Alnus nitida (800) followed by Albizia chinensis (75) and Acacia catechu (61). However, the nodulation found to be delayed in Alnus nitida. The shapes of their nodules were spheroidal imbedded with small beads, palmate type and more or less cylindrical, respectively. The nodulation was found to be increased with the increase in age of the plants from 3 months to 18 months. However, good size of nodules with regard to age of plants was observed at the age of 9 months. Though most of the nodules were concentrated on laterals yet the earliest nodulation was observed on tap root. The highest nitrogen content was recorded in roots and shoots of Alnus nitida followed by Albizia chinensis and Acacia catechu. Contrary to this, maximum nitrogen content was recorded in nodules of Acacia catechu and minimum in Alnus nitida. Alnus nitida (14.10 kg ha-1yr-1) fixed the highest quantity of nitrogen followed by Albizia chinensis (8.84 kg ha-1yr-1) and Acacia catechu (7.41 kg ha-1yr-1).