Effect Of Azotobacter Research Articles

Characterization ofAzotobacter spp. and effect of Azotobacter and Azospirillum as inoculant on the yield and N-uptake of wheat crop

Out of ten isolates ofAzospirillum spp. isolated from the root and rhizosphere of wheat plant, seven belonged toA. brasilense and three belonged toA. lipoferum. All eight isolates ofAzotobacter spp. belonged toAzotobacter chroococcum. Two strains, one fromA. lipoferum and another fromA. chroococcum having high nitrogen fixing capacity with negative test for denitrification were used as inoculant to supplement the nitrogen need of wheat crop. Significant increases in the yield of wheat grain and uptake of nitrogen by the crop over the control were found in pot tests when the seeds were inoculated either withAzospirillum spp. orAzotobacter spp. or the combination of both the inoculants.

Effect ofAzotobacter chroococcum on the hatching of egg masses and eggs ofMeloidogyne incognita

Investigations were carried out to study the effect ofAzotobacter chroococcum VP-5 on the hatching of egg masses and eggs ofMeloidogyne incognita in vitro. Eggs were more susceptible and required lesser time for antagonistic action of Azotobacter than egg masses.

Effect of Azotobacter and GA 3 on mycoflora of green and dry leaves of soybean

Summary The effect of different concentrations of GA 3 and Azotobacter spraying at various stages of development of the plants on mycoflora, associated with green and dry leaves of soybean, was studied. It has been found that the total fungal population was reduced by both, however, GA3 showed greater effect when compared to Azotobacter . The growth of some fungi was stimulated or suppressed, whereas others were unaffected. GA 3 and Azotobacter affected the growth of 12 fungal species out of 52 species in similar pattern on dry and green leaves. However, forty species showed the response to both treatments in varying fashions. The effect of GA 3 and Azotobacter differed on fungal populations of green and dry leaves, although data recorded from treated dry leaves was insignificant.

Effect ofAzotobacter chroococcum andAzospirillum brasilense inoculation under graded levels of nitrogen on growth and yield of wheat

A field experiment was conducted to study the effect ofAzotobacter chroococcum andAzospirillum brasilense inoculation under graded levels of fertilizeer nitrogen (0, 30, 60, 90, 120 kg/ha) on wheat (Triticum durum Desf. var. HD2189). The results revealed that both the inolculants sigificnatly increased the growth parametersviz. tilles, dry-matter accumulation, grain yield and protein content of wheat gains. Fertilizer—N @ 90 kg/ha with both inoculations was found to be the most responsive, however 120 kg/ha with Azospirillum inoculation recorded maximum number of tillers (3.5/plant), dry-matter accumulation (13.5 g/plant), grain yield (41.9 g/ha) and protein content in grains (13.3%). Maximum percent increase in grain yeidl with Azospirillum (25.8%) and Azotobacteer (19.2%) over uninoculated control was observed at 90 kg N/ha level. Azospirillum inoculation, Azotobacter inoculation and uninoculated control significnatly differed between each other.

Effect of Azotobacter on germination of spores of different fungi

Summary Azotobacter cultures which were studied for their fungistatic action towards different plant pathogenic fungi in iquid medium were used to assess their effect on spore germination of Alternaria (5 cultures), Curvularia (5 cultures) Corynespora (1 culture), Fusarium (3 cultures) and Helminthosporium (4 cultures). The germination percentage was recorded at the end of 6 hours at 30 °C.

Effect of Azotobacter in Summer Irrigated Cotton

Field experiments were conducted during summer 1975 and 1976, to study the efficacy of Azotobacter on summor irrigated cotton (Var. MCU: 8). The study revealed that application of Azotobacter cither to seed or soil was superior to no treatment. Treating cotton seeds with Azotobacter and broadcasting and mixing the culture in the soil before sowing at 75 per cent recommended dose of N was the most beneficial treatment, since the requirement of nitrogen to cotton, crop was reduced by 25 per cent with increased seed cotton yield.

Effect of Association of Azotobacter with Nitrogenous Fertilizer on Yield of Paddy

The effect of Azotobacter with different levels of nitrogenous fertilizer viz., 50 62.5, 75, 87.5 and 100 kg N/hs through urea on the yield of paddy was studied. The seeds, seedlings and soil were inoculated with efficient strain of Azotobacter. The results of the experiment were statistically significant. The response of Azotobacter was also found significant. In each case the application of Azotobacter with different levels of nitrogen fertilizer gave more yield than control. The Azotobacter alone gave higher yield over 50 kg N/ha applied as urea. In general, the yield of paddy was found to be increased to the extent of 28 per cent when nitrogen was applied with Azotobacter. The data indicated that seed inoculation with Azotobacter would reduce fertilizer nitrogen requirement to certain extent.

Effect of Azotobacter on Rice Crop

Azotobacter treatment to seed seedling and soil helped good initial plant growth and better tillering of paddy. When applied in combination with 75 per cent of the re- commended dose of fertilizer nitrogen, the Azotobater could compensate 25 per cent of fertilizer N and bring out the same yield of paddy crop as that of cent per cent fertilizer N without Azotobacter treatment, thereby reducing the cost of cultivation. Azotobacter treatment with cent per cent of the recommended dose of fertilizer N resulted in the increase of grain yield slightly. Azotobacter treatment to paddy during January-May season brought out the beneficial effects convincingly than during the August-December season.

Stimulatory effects of Azotobacter chroococcum exudates in culture and soil on its nitrogen fixation.

The effect of the exudates of Azotobacter chroococcum in nitrogen-free liquid medium and in sterile soil, on its ability to fix nitrogen was studied. Cell-free culture filtrates and water extract of sterile soil inoculated with Azotobacter were fractionated into ether soluble and insoluble aliquots, concentrated and chromatographically separated into ten consecutive zones. These were eluted and tested for their effect on nitrogen fixation by Azotobacter. UV-fluorescence, and chemical tests for indoles, reducing substances, amino acids, and hydroxyl groups were made. Detection of gibberellins and water soluble vitamins was attempted. A biological test for activity of indolic compounds was carried out. The results showed that Azotobacter produces biologically active indolic compounds in culture and soil, acting as a significant stimulation for the process of nitrogen fixation. Not all the zones of the chromatogram which were stimulatory for nitrogen fixation were the same for coleoptile growth and vice versa. Amino acids in some cases were associated with non-significant stimulation of nitrogen fixation. An indication was obtained suggesting the possible stimulation of nitrogen fixation by gibberellins produced in culture and soil by Azotobacter. Suggestion was given for studying the effect of individual gib berellic compounds on the nitrogen fixation process, with a view to their interaction with amino acids and indolic compounds.

Effect of Azotobacter on fixed nitrogen

The rate of uptake of nitrite and nitrate by A. vinelandii has been measured; at the same time, the rate of formation and disappearance of ammonia (in the case of nitrite) and of both nitrite and ammonia (in the case of nitrate) have been determined. The results indicate that when nitrite is supplied ammonia is formed at almost the same rate as the nitrite disappears; similarly, the rate of appearance of nitrite, and subsequently of ammonia, coincides closely with the rate at which the nitrate disappears from the medium. The results are discussed in relation to the metabolism of the bacteria.