Nitrogen Fixation Activity of Twenty Leguminous Tree Species in Eastern Nepal

  • Himmat K.C. Singh K.C. Eastern Regional Foerstry Directorate, Biratnagar; Morang
  • T.C Pokhriyal Plant Physiology, Forest Research Institute, Dehra Dun - 248806


Nitrogen fixing trees (NFTs) are being widely adopted for multipurpose uses because of their unique ability to fix atmospheric nitrogen which helps in restoration and maintenance of soil fertility. The forests in Eastern Nepal have been under continuous degradation and are in need of remedial measures to restore their productivity. A feasible solution to rejuvenate the sites is through the introduction of indigenous and locally suitable NFTs. Therefore, a study was conducted to observe nodulation and nitrogenase activity in twenty leguminous trees, with potential for use in such programmes. The study was primarily based on seedlings raised in the nursery at Biratnagar. Locally collected seeds were used in the nursery. A great variation in the production of nodules and nitrogenase activity of the species even within the same genus was recorded. Maximum (818.3) active nodules were observed in Albizia julibrissin and minimum (33.9) in Samanea saman, however, the highest (26206.0 n moles) total nitrogenase activity occured in Sesbania grandiflora and lowest (10.0) in Samanea saman. Similarly, maximum (202.2) inactive nodules were recorded in Sesbania grandiflora and minimum (4.1) in Acacia auriculifomzis. The variations recorded in the study are regarded to be influenced by climatic as well as physio-chemical factors.