Summary
15N tracer was used to detect the extent to which nitrogen of appliedAzolla caroliniana, Anabaena variabilis andNostoc muscorum was available for assimilation by the growing rice plants in pots under 4 cm flood water for 60 days. The rate of release of nitrogen from the above biofertilizers, the amount of nitrogen remaining in the soils and the amount that was lost from the soils during this period were also examined. Previously15N-labelled biomass of Azolla, Anabaena and Nostoc to provide 40 mg N was mixed thoroughly with 0.5 kg silt loam Bangladesh soil (Sonatola series) in each of three pots used for a single treatment. Each pot received four 16 days old IR8 rice seedlings. A parallet set of experiments was conducted without rice plants.
It was found that nitrogen uptake in the rice plants was increased by 91, 176 and 215% on using Azolla, Anabaena and Nostoc which resulted in increased total dry matter yields (shoot plus root) of 74, 105 and 125%, respectively. Of the total15N applied at the start, 26, 49 and 53% was released from Azolla, Anabaena and Nostoc; about 7, 14 and 13% was lost by denitrification and 74, 51 and 47% remained in the soils as the undecomposed part of the biofertilizers, respeciively, after 60 days. Of 15.76, 22.72 and 25.92 mg N assimilated by the rice plants, 48, 61 and 62% was supplied by Azolla, Anabaena and Nostoc, respectively. The rest was obtained from the soil used.
In the absence of the rice plants 30, 43 and 45% of applied15N of Azolla, Anabaena and Nostoc was released, respectively, in 60 days of which 93–96% was lost as N2 through denitrification.
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References
Bremner J M 1965 Inorganic forms of nitrogen.In Methods of Soil Analysis. part 2. Ed. C A Black pp 1179–1237. Am. Soc. Agron., Madison, Wis.
Bremner J M 1965 Total nitrogen.In Methods of Soil Analysis, part 2. Ed. C A Black pp 1149–1178. Am. Soc. Agron., Madison, Wis.
Bremner J M 1965 Isotope ratio analysis of nitrogen in N-15 tracer investigations.In Methods of Soil Analysis, part 2. Ed. C A Black pp 1256–1286. Am. Soc. Agron., Madison, Wis.
Bremner J M and Edwards A P 1965 Determination and isotope ratio analysis of different forms of nitrogen in soils. I. Apparatus and procedure for distillation and determination of ammonium. Soil Sci. Soc. Am. Proc. 29, 504–507.
Lumpkin T A and Plucknett D L 1980Azolla: Botany, physiology and use as a green manure. Economic Botany 34, 111–153.
Mian M H and Stewart W D P 1984 A study on the availability of biologically fixed atmospheric dinitrogen byAzolla-Anabaena complex to the flooded rice crops.In Proceedings of First Intern. Workshop on Practical Application of Azolla for Rice Production. Eds. W S Silver and E C Schröder, pp 168–175. Martinus Nijhoff/Dr W. Junk, The Netherlands.
Peters G A and Mayne B C 1974 TheAzolla, Anabaena azollae relationship. I. Initial characterization of the association. Plant Physiol. 53, 813–819.
Roger P A and Kulasooriya S A 1980 Blue-green Algae and Rice, IRRI, Los Bonos, Laguna, Philippines.
Shi S L, Wen QX and Liao H Q 1980 The availability of nitrogen of green manures in relation to their chemical composition. Acta. Pedologica Sinica 17, 240–246.
Stanier R Y, Kunisawa R, Mandel M and Cohen-Bazire G 1971 Purification and properties of unicellular blue-green algae (Order Chroococcales). Bacteriol. Rev. 35, 171–205.
Tirol A C, Roger P A and Watanabe I 1982 Fate of nitrogen from a blue-green alga in a flooded rice soil. Soil Sci. Plant Nutr. 28, 559–569.
Venkataraman G S 1981 Blue-green algae for rice production—a manual for its promotion. FAO Soils Bull. 46, 102 pp.
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Mian, M.H., Stewart, W.D.P. Fate of nitrogen applied as Azolla and blue-green algae (Cyanobacteria) in waterlogged rice soils—a15N tracer study. Plant Soil 83, 363–370 (1985). https://doi.org/10.1007/BF02184448
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DOI: https://doi.org/10.1007/BF02184448