Summary
The dynamics of five inoculated strains of heterocystous blue-green algae (BGA) and indigenous algae were studied for 1 month in 1-m2 microplots of five soils previously air-dried or oven-dried. The same soils were then dried and resubmerged for another 2 months to study the effect of controlling algal grazers with neem (Azardirachta indica) seeds on the revival and dynamics of indigenous and inoculated algae. During the month following inoculation, inoculated BGA multiplied to some extend in all soils but never dominated the total algal flora. They rarely dominated the indigeneous heterocystous BGA, and did so only when the growth of N2-fixing BGA was poor or after the decline of blooms of indigenous strains. Once the soils were dried, two of the five inoculated strains did not reappear. During the 1st month following rewetting, the remaining inoculated strains again exhibited poor growth; however, after 2 months of submergence, inoculated Aulosira fertilissima developed an agronomically significant bloom in neem-treated plots of two soils. Correlations between acetylene-reducing activity and heterocystous BGA populations indicated a major contribution by indigenous BGA and a minor contribution by inoculated BGA to the N2-fixing activity of the soils during the first experiment and the 1st month of the second experiment. The establishment of inoculated BGA exhibited clear differences among strains but was less affected by the nature of the soil and heat treatment. Neem application might have had a delayed positive effect on the late establishment of inoculated A. fertilissima and favored BGA growth and N2 fixation by the total algal population.
Similar content being viewed by others
References
De PK (1939) The role of blue-green algae in nitrogen fixation in rice fields. Proc R Soc B 127:121–139
Grant IF, Roger PA, Watanabe I (1985) Effect of grazer regulation on photodependent nitrogen fixation in a wetland rice field. Biol Fertil Soils 1:61–72
Johansen RJ, Javakul A, Rushforth S (1982) Effect of burning on the algal communities of a high desert soil near Wallsburg. Utah J Range Manage 35:598–600
Roger PA, Kulasooriya SA (1980) Blue-green algae and rice. Int Rice Res Inst (Los Baños)
Roger PA, Ardales S, Watanabe I (1985) Unicellular blue-green algae: impressive blooms but deceptive biofertilizers. Int Rice Res News 110:27–28
Singh PK (1973) Nitrogen fixation by the unicellular blue-green alga Aphanothece. Arch Microbiol 92:59–62
Stanier RY, Kunisawa R, Mandel M, Cohen-Bazire G (1971) Purification and properties of unicellular blue-green algae (Order Chroococcales) Bacteriol Rev 3:171–205
Subrahmanian R, Relwani LL, Manna GB (1964) Role of blue-green algae and different methods of partial sterilization on rice yield. Proc Ind Acad Sci B 60:293–297
Venkataraman GS (1972) Algal biofertilizers and rice cultivation. Today and Tomorrow's Printers and Publishers, Faridabad (Haryana)
Venkataraman GS (1981) Blue-green algae for rice production. A manual for its promotion. FAO Soil Bull 46
Wieringa KT (1968) A new method for obtaining bacteria-free cultures of blue-green algae. Antonie van Leeuwenhoek 34:54–56
Author information
Authors and Affiliations
Additional information
Visiting Scientist at IRRI
Rights and permissions
About this article
Cite this article
Reddy, P.M., Roger, P.A. Dynamics of algal populations and acetylene-reducing activity in five rice soils inoculated with blue-green algae. Biol Fert Soils 6, 14–21 (1988). https://doi.org/10.1007/BF00257914
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00257914