IN SITU NITROGEN FIXATION BY WHITE CLOVER IN MIXED SWARDS IN NOVA SCOTIA

1984 ◽  
Vol 64 (3) ◽  
pp. 625-636 ◽  
Author(s):  
J. K. VESSEY ◽  
D. G. PATRIQUIN
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Management Strategy ◽  
Acetylene Reduction Activity ◽  
Total Rainfall ◽  
Reduction Activity ◽  
Main Factors ◽  
Low Levels ◽  
A Site

At three sites, clover cover increased from less than 10% in April to 50–70% during anthesis in July. It began to decline in September, reaching 20–30% in December. Acetylene-reduction activity (ARA), measured by an in situ technique, commenced in April when soil temperature was 5–7 °C. "Clover-specific ARA" (ARA measured in clover patches where cover of clover was 100%) was generally high through most of May, June and July, and then declined, reaching low levels by November. Clover-specific ARA was correlated with total rainfall during the period between 7 and 28 days before the assay (r = 0.720, P < 0.01). The amount of N2 fixed by white clover over a 1-yr period was estimated at 66 and 81 kg N/ha for two pasture sites and 100 kg N/ha at a lawn site. Clover cover and thermal regime appeared to be the two main factors influencing the amount of N2 fixed by white clover at a site. Eight sites of widely varying clover cover (2–53%) were compared in July with regard to cover, clover-specific ARA, edaphic characteristics and fertilizer and grazing management. Management strategy appeared to have the greatest influence on clover abundance in pasture.Key words: White clover, Trifolium repens, nitrogen fixation

Nitrogen fixation activity by white clover pastures during flood irrigation cycles

1988 ◽  
Vol 39 (3) ◽  
pp. 409 ◽  
Author(s):  
GN Mundy ◽  
HR Jones ◽  
WK Mason
Keyword(s):  
Nitrogen Fixation ◽  
Water Stress ◽  
White Clover ◽  
Nitrogen Fertilizer ◽  
Ethylene Production ◽  
Acetylene Reduction ◽  
Acetylene Reduction Activity ◽  
Flood Irrigation ◽  
Reduction Activity ◽  
Nitrogen Fixation Activity

The effect of flood irrigation on clover nitrogen fixation (acetylene reduction activity) was investigated in unfertilized pastures and pastures fertilized with 100 kg N/ha as NH4N03. During the experiment acetylene reduction activities were monitored between successive flood irrigations. The rate of ethylene production increased with decreasing soil water content, peaking 13 days after irrigation. Measured nodule activity then declined, possibly owing to water stress. Nitrogen fertilizer reduced acetylene reduction activities to about half that of the unfertilized pastures. For most of the irrigation cycle acetylene reduction by the pasture was below the measured maximum.

Corrigendum - Nitrogen fixation activity by white clover pastures during flood irrigation cycles

1988 ◽  
Vol 39 (3) ◽  
pp. 409
Author(s):  
GN Mundy ◽  
HR Jones ◽  
WK Mason
Keyword(s):  
Nitrogen Fixation ◽  
Water Stress ◽  
White Clover ◽  
Nitrogen Fertilizer ◽  
Ethylene Production ◽  
Acetylene Reduction ◽  
Acetylene Reduction Activity ◽  
Flood Irrigation ◽  
Reduction Activity ◽  
Nitrogen Fixation Activity

The effect of flood irrigation on clover nitrogen fixation (acetylene reduction activity) was investigated in unfertilized pastures and pastures fertilized with 100 kg N/ha as NH4N03. During the experiment acetylene reduction activities were monitored between successive flood irrigations. The rate of ethylene production increased with decreasing soil water content, peaking 13 days after irrigation. Measured nodule activity then declined, possibly owing to water stress. Nitrogen fertilizer reduced acetylene reduction activities to about half that of the unfertilized pastures. For most of the irrigation cycle acetylene reduction by the pasture was below the measured maximum.

A survey of nitrogen fixation (acetylene reduction) associated with Typha in Minnesota

1988 ◽  
Vol 66 (12) ◽  
pp. 2419-2423 ◽  
Author(s):  
Nancy A. Eckardt ◽  
David D. Biesboer
Keyword(s):  
Nitrogen Fixation ◽  
Regression Analysis ◽  
Acetylene Reduction ◽  
Substantial Reduction ◽  
Reduction Technique ◽  
Acetylene Reduction Activity ◽  
Typha Angustifolia ◽  
Reduction Activity ◽  
Nitrogen Requirement

The acetylene-reduction technique was used on soil–root cores to examine the three species of Typha (Typhaceae) found in Minnesota for differences in rates of nitrogen fixation by associated rhizosphere diazotrophs. In 20 cattail stands sampled in 1985, Typha angustifolia showed a tendency for lower acetylene-reduction activity per ramet, with an average of 2.9 μmol∙ramer−1∙d−1, than T. latifolia and T. ×glauca, with averages of 6.5 and 7.1 μmol∙ramet−1∙d−', respectively. Regression analysis showed no significant differences in these values due to the variability within as well as between stands, and fixation rates were uncorrelated with the pH, soil percent carbon, and soil moisture of the study stands. In 1986, in situ assays of soil–root cores of ramets of T. angustifolia and T. latifolia from adjacent monospecific stands produced average acetylene-reduction rates of 1.4 for T. angustifolia and 1.8 μmol∙ramet−1∙d−1 for T. latifolia, with a substantial reduction in variability within stands over the 1985 data. It is estimated that, contrary to previously published reports, populations of Typha may receive as little as 1–2% of their annual nitrogen requirement from nitrogen fixation.

Nitrogen fixation associated with 'Park' Kentucky bluegrass (Poapratensis L.)

1979 ◽  
Vol 25 (10) ◽  
pp. 1197-1200 ◽  
Author(s):  
R. C. Shearman ◽  
W. L. Pedersen ◽  
R. V. Klucas ◽  
E. J. Kinbacher
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Acetylene Reduction Activity ◽  
Controlled Environment ◽  
Nitrogen Accumulation ◽  
Reduction Activity ◽  
Significant Difference ◽  
Reduction Assay

Associative nitrogen fixation in Kentucky bluegrass (Poa pratensis L.) turfs inoculated with five nitrogen-fixing bacterial isolates was evaluated using the acetylene reduction assay and nitrogen accumulation as indicators of fixation. 'Park' and 'Nugget' Kentucky bluegrass turfs were grown in controlled environment chambers and inoculated with Klebsiella pneumoniae (W-2, W-6, and W-14), Erwinia herbicola (W-8), and Enterobacter cloacae (W-11). 'Park' inoculated with K. pneumoniae (W-6) had significant acetylene reduction activity using undisturbed turfs. Other treatments including turfs treated with heat-killed cells had no significant difference in acetylene reduction. In a second study, 'Park' and 'South Dakota Certified' turfs were grown in a greenhouse and inoculated with K. pneumoniae (W-6) and E. herbicola (W-8). 'Park' inoculated with K. pneumoniae (W-6) had increased acetylene reduction activity rates and also a greater nitrogen accumulation in aerial tissues when compared to controls. Acetylene reduction activity was correlated (r = 0.92) to nitrogen accumulation. Other treatments did not effectively increase acetylene reduction activity or nitrogen accumulation.

A survey of angiosperms in Nova Scotia for rhizosphere nitrogenase (acetylene-reduction) activity

1978 ◽  
Vol 56 (18) ◽  
pp. 2218-2223 ◽  
Author(s):  
D. Smith ◽  
D. G. Patriquin
Keyword(s):  
Nova Scotia ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Reduction Technique ◽  
Acetylene Reduction Activity ◽  
Forage Grasses ◽  
Reduction Activity ◽  
Tropical Forage ◽  
Poorly Drained Soils

Excised root samples from 901 plants, representing 130 species of nonnodulated angiosperms largely in upland, pioneering habitats, were assayed for nitrogenase activity by the acetylene-reduction technique after overnight preincubation of the samples under low pO2. Most samples and most species exhibited very low excised root acetylene-reducing activities, but for 19 species, maximum values were greater than 50 nmol C2H4∙g−1∙h−1. In situ C2H2 assays, conducted on 10 species which had exhibited maximum excised root activities greater than 10 nmol C2H4∙g−1∙h−1, indicated average belowground N2-fixation rates of 3 to 92 g N∙ha−1∙day−1 and maxima greater than 100 g N∙ha−1∙day−1 for 3 of the 10 species. The highest values were for grasses characteristic of poorly drained soils and for some dicotyledonous weeds. It is concluded that the potential of temperate-zone angiosperms for nitrogenase activity by 'associative symbioses' approaches that of tropical forage grasses.

scholarly journals Inoculation for successful establishment of Caucasian clover

1994 ◽  
pp. 101-105 ◽  
Author(s):  
Heather N. Patrick ◽  
W.L. Lowther ◽  
K.D. Trainor
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Symbiotic Nitrogen Fixation ◽  
Gum Arabic ◽  
Trifolium Ambiguum ◽  
Successful Establishment ◽  
Low Levels ◽  
Very High

Results from oversowing trials in the tussock grasslands have shown that nodulation problems can limit the establishment of Caucasian clover (Trifolium ambiguum). They also strongly suggest that previously reported difficulties with establishment of Caucasian clover, in areas where white clover (T. repens) had established sucessfully, were likely to be due to inoculation failures due to low numbers of rhizobia on the seed, or in the case of tetraploid cultivars, to the use of an unsatisfactory strain. With the tetraploid cultivar Treeline, inoculation with the recommended strain ICMP4074b resulted in low levels of effective seedling nodulation even with very high levels of rhizobia/seed at sowing (149 000). Treeline seedling nodulation was increased when inoculated with strain ICMP4073b, the approved strain for hexaploid cultivars, and the strain was effective at symbiotic nitrogen fixation. Effective seedling nodulation of both tetraploid Treeline and hexaploid Monaro cultivars inoculated with ICMP4073b increased as the number of rhizobia on the seed at sowing was increased. Low levels of seedling nodulation occurred when populations of rhizobia on the seed were in the range likely to be present when seed is slurry inoculated, or inoculated and pelleted and stored for several days before oversowing. To maximise effective nodulation, seed should be inoculated at least 5 times the recommended rate, with the incorporation of gum arabic in the slurry or pellet and oversown within one day. Keywords: Caucasian clover, establishment, inoculation, nodulation, rhizobia, Trifolium ambiguum

A Spot Test for Estimating Ureides in Soyabean Petioles

1986 ◽  
Vol 22 (4) ◽  
pp. 405-416 ◽  
Author(s):  
Richard A. Glenister ◽  
Thomas A. LaRue
Keyword(s):  
Nitrogen Fixation ◽  
Spot Test ◽  
Acetylene Reduction Activity ◽  
Colorimetric Determination ◽  
Reduction Activity ◽  
Nitrogen Fixation Activity ◽  
Bright Pink ◽  
Low Nitrogen ◽  
Petiole Segment

SUMMARYThe ureides allantoic acid and allantoin form a bright pink compound with acidic p-dimethylamino cinnamaldehyde. It is possible to estimate the ureide content of a soyabean petiole segment by crushing it on filter paper and developing the colour with this reagent. There is a strong correlation between the spot test and estimates from colorimetric determination of ureides. In field grown soyabeans, there was a positive correlation between the petiole ureide content during pod fill and the integrated seasonal acetylene reduction activity. The spot test can be used to identify plants with low nitrogen fixation activity.

Variabilité génotypique de l'aptitude à la fixation symbiotique de l'azote chez Acacia cyanophylla Lindl.

1999 ◽  
Vol 77 (1) ◽  
pp. 77-86
Author(s):  
Hafedh Nasr ◽  
Tahar Sghaier ◽  
Mohamed Habib Ghorbal ◽  
Yvon René Dommergues
Keyword(s):  
Nitrogen Fixation ◽  
Factorial Analysis ◽  
Qualitative Assessment ◽  
Behaviour Pattern ◽  
Acetylene Reduction Activity ◽  
Genotypic Variability ◽  
Reduction Activity ◽  
Acacia Cyanophylla ◽  
Rhizobium Strains ◽  
Seed Origin

Genotypic variability of the symbiotic nitrogen fixation ability on Acacia cyanophylla Lindl. The phenotypic and functional characteristics of four rhizobium strains isolated from nodules of Acacia cyanophylla Lindl., syn. Acacia saligna (Labill.) H. Wendl., and the inoculated host-plant genetic variability were evaluated. The evaluation used permitted the ranking of the tested rhizobium strains and seedlots according to their performance. The growth pattern of these strains indicated that A. cyanophylla was able to nodulate and fix N2 with slow- and fast-growing rhizobium strains. The acetylene reduction activity test reflected a variable effectiveness of the strains depending on their site of isolation. Strains RFH383 and RFH483 were more effective than RFH183 and RFH283. The high antibiotic resistance acquisition by RFH183 and RFH283 strains seemed to be inversely related to their effectiveness. Acacia cyanophylla seedlings from five seedlots displayed a high variability regarding their growth, nodulation, and ability to fix nitrogen. The ability to fix nitrogen was greater in the seedlings from KL seedlot than those from EN, KR, and TZ seedlots. The qualitative assessment of the seedlots using correspondence factorial analysis showed that the seedlings from KL seedlot preformed better than those from KR and TZ. The seedlings from TN and EN seedlots displayed an intermediate behaviour pattern. Seed origin seemed to affect the growth, nodulation, and nitrogen fixation of inoculated A. cyanophylla. The behaviour of this species and that of its associated rhizobium strains appeared to be very sensitive to variations in site characteristics. Results suggested that the association between plants derived from KL seedlot and RFH383 strain may represent the best partnership allowing the improvement of symbiotic nitrogen fixation.Key words: Acacia cyanophylla, rhizobium, nodulation, N2 fixation, genotypic variability, correspondence factorial analysis.

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