Perubahan Kadar N Tersedia Dan Populasi Azotobacter Di Rizosfer Sorgum (Sorghum bicolor L.) Yang Ditanam Di Dua Ordo Tanah Dengan Inokulasi Azotobacter sp.

Abstract

Bioagumentation by used of nonsimbiotic N­₂ fixing Azotobacter  is a way to enhance soil N availability in sustainable Agricultural land.  A green house experiment has been done to verify effect of Azotobacter sp. inoculation in two soil order, Inceptisols and Entisols, on NH₄⁺danNO₃^- content , N uptake as well as Azotobacter population in rhizosphere soil of sorghum (Sorghum bicolor L.). Experiment was set up in Randomized Block Design with eight treatments and three replicates, sorghum was maintained in green house until maximum vegetative phase. Resuls showed that Azotobacter sp. AS4 was more enable to increase the availability of soil N rather than isolate AS3.  Bacterial  bioaugmentation with Azotobacter sp. AS4 on Inceptisols increased more NO₃^-, Azotobacter sp. population in soil rhizosphere and shoot height of sorghum genotype 2.24.