Seasonal change of N2 fixing rate in rice field assayed by In Situ acetylene reduction technique

Abstract A technique to estimate the quantity of N2 fixed in the flooded water on the rice field and in association with the rice plant is described. Removal of the flood water and the surface soil and addition of fresh water eliminated the bulk of N2 fixation associated with the blue-green algae. After the algal activity was eliminated, the acetylene reduction activity was higher in planted soils than that in fallow soils. Some N2 fixation is, therefore, associated with the presence of the rice plant. In an IRRI unfertilized flooded rice field, algal acetylene reduction activity was estimated to be 200 mmol C2H4/m2 in the wet season (163 days) and 300 nunol C.H,/ml in the dry season (168 days). Acetylene reduction activity associated with the rice plant (IR26) was calculated to be 90 nunol C2H4/m2 in wet season (163 days) and 50 mmol C2H4/m2 in the dry season (168 days, IR36). Similar rates were obtained at a second site in the Philippines. N2 fixation was associated with both the stems and roots of wetl...

[1]  I. Watanabe,et al.  Seasonal change of N2-fixing rate in rice field assayed byIn Situacetylene reduction technique:I. Experiments in long-term fertility plots , 1978 .

[2]  I. Watanabe,et al.  Problems of the Acetylene Reduction Technique Applied to Water-Saturated Paddy Soils , 1977, Applied and environmental microbiology.

[3]  T. Matsuguchi,et al.  Free-living nitrogen fixers and acetylene reduction in tropical rice field , 1974 .

[4]  Y. Dommergues,et al.  Diurnal variations of nitrogenase activity in the field. , 1974, Applied microbiology.

[5]  E. Paul,et al.  The acetylene reduction assay for measuring nitrogen fixation in waterlogged soil. , 1971, Canadian journal of microbiology.

[6]  E. Takahashi,et al.  DISTRIBUTION OF NITROGEN‐FIXING MICROORGANISMS IN PADDY SOILS OF SOUTHEAST ASIA , 1967 .

[7]  P. Roger,et al.  Ndn2-fixing algal biomass in Senegal rice fields. , 1978 .

[8]  Y. Dommergues,et al.  Non-symbiotic nitrogen fixation in the rhizospheres of rice, maize and different tropical grasses , 1973 .

[9]  F. Bergersen,et al.  Kinetic studies of nitrogenase from soya-bean root-nodule bacteroids. , 1973, The Biochemical journal.

[10]  Tomio Yoshida,et al.  The fixation of atmospheric nitrogen in the rice rhizosphere , 1973 .

[11]  Tomio Yoshida,et al.  Nitrogen-Fixing Activity in Upland and Flooded Rice Fields 1 , 1973 .

[12]  Tomio Yoshida,et al.  Nitrogen Fixation by Bacteria in the Root Zone of Rice , 1971 .

[13]  F. Bergersen.  The Quantitative Relationship between Nitrogen Fixation and the Acetylene-Reduction Assay , 1970 .