NITROGEN FIXATION AND NITROGEN-FIXING MICROORGANISMS FROM THE RHIZOSPHERE OF DIPLACHNE FUSCA LINN. (BEAUV.)

Abstract

The soil cores of a salt tolerant grass Diplachne fusca Linn. Beauv. Commonly grown in the saline-sodic area of Pakistan showed high nitrogenase activity. High input values of N, up to 127 kg/ha/100 days were obtained by extrapolating the acetylene reduction values. Anabaena variabilis was isolated from the soil, and isolated algae showed values of nitrogenase activity and ¹⁵N incorporation comparable to those of A. cylindrica. Enrichment assays resulted in recovery of several N₂-fixing bacteria. Some characteristics of the most efficient isolate were studied, which suggests that the isolate belongs to genus Azospirillum. However, confirmative identification with the collaboration of the German Collection of Microorganisms, Gottingen, is in progress.