EFFECT OF AZOTOBACTER AND AZOSPIR1LLUM ON GROWTH AND YIELD OF RICE GROWN ON TIDAL SWAMP RICE FIELD IN SOUTH KALIMANTAN

Tidal swamp land is a potential area for rice cultivation. However, tidal swamp is fragile ecosystems, so that when this area is used for rice cultivation, it has to be done carefully. To reduce a risk of environmental pollution in the tidal swamp area due to rice cultivation, the area should be managed properly and wisely especially when using agrochemicals such as fertilizers and pesticides. In relation to this, the use ofbio-Jertilizer such as Azotobacter orland Azospirillum, an atmospheric nit.yogenfixifJg bacterium, might be an important thingfor this area. The objectives ofthis study were to evaluate the number of NFB (i.e. Azotobacter and Azospirillum spp.) found in tidalswamp rice fields of South Kalimantan, and their ability in fixing atmospheric nitrogen and supplying this fixed nitrogen to rice, and in increasing rice yields. There were three research stages performed in this study. The first, collecting, isolating and purifying the NFB on the selective media ofnitrogen free media. The second, a hydroponic experiment in the greenhouse using Yoshida nutrition solution (Yoshida et aI., 1976 in IRRl, 2003) as culture media and selected Azotobacter and Azospirillum. The third experiment was to study the efJect of selected Azotobacter isolates to increase growth and yield of IR64 and Margasari rice cultivars, and two Azotobacter isolates were combined with six inoculation methods for Siam Unus rice cultivar as treatments. The result showed that the number ofNFB strains found in rhizospere rice cultivars were varied widely. Then, Azotobacter and Azospirillum spp selectedfrom rice fields in the tidal lCmd of South Kalimantan when associated with IR64 and Siam Unus rice cultivars have ability in fixin