Correction - Studies in the nodulation of Kenya white clover (Trifolium semipilosum) under field conditions in south-east Queensland

1975 ◽  
Vol 15 (75) ◽  
pp. 519
Author(s):  
RM Jones ◽  
RA Date
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Nitrogen Deficiency ◽  
Dry Weight ◽  
Field Conditions ◽  
N Fixation ◽  
Original Strain ◽  
Serological Identification ◽  
Seed Application ◽  
Inoculum Strain

The nodulation of Kenya white clover (Trifolium semipilosum) was examined under field conditions to evaluate reported establishment problems attributed to poor nodulation. Two isolates of Rhizobium identified as strain CB782 were obtained from nodules of T. semipilosum located in separate field sowings each of which was considered an establishment failure but which had recovered to healthy stands at the time of sampling. The two isolates were compared with a laboratory maintained culture of CB782 for nodulation and nitrogen fixation. Both isolates and the original strain were equally effective in N-fixation and all three increased plant dry weight, per cent plants with effective (pink) nodules and amount of nitrogen fixed compared with an uninoculated control. Increasing the level of seed application of inoculum up to the normal rate increased effective nodulation, but excess inoculum levels resulted only in greater numbers of smaller effective (pink) nodules without any increase in nodule dry weight. High inoculum levels decreased the number of white and green nodules compared with the control. Over 50 per cent effective nodulation was obtained with less than 50 Rhizobium seed-1 at sowing. Serological identification and effectiveness tests of strains in nodules confirmed that most white and green nodules on T. semipilosum resulted from infection by naturally occurring white clover rhizobia. These were ineffective in nitrogen fixation with T. semipilosum but fully effective on T. repens. Serological typing of nodules also indicated that normal levels of inoculation resulted in more than 80 per cent of nodules being formed by the specific inoculum strain. We conclude that field sowings of T. semipilosum can be effectively nodulated by the specific inoculum strain CB782 which is both effective and persistent under south-east Queensland conditions. We suggest that most reported nitrogen deficiency symptoms of establishing T. semipilosum are due to infection by Rugose Leaf Curl Virus.

Studies in the nodulation of Kenya white clover (Trifolium semipilosum) under field conditions in south-east Queensland

1975 ◽  
Vol 15 (75) ◽  
pp. 519
Author(s):  
RM Jones ◽  
RA Date
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Nitrogen Deficiency ◽  
Dry Weight ◽  
Field Conditions ◽  
N Fixation ◽  
Original Strain ◽  
Serological Identification ◽  
Seed Application ◽  
Inoculum Strain

The nodulation of Kenya white clover (Trifolium semipilosum) was examined under field conditions to evaluate reported establishment problems attributed to poor nodulation. Two isolates of Rhizobium identified as strain CB782 were obtained from nodules of T. semipilosum located in separate field sowings each of which was considered an establishment failure but which had recovered to healthy stands at the time of sampling. The two isolates were compared with a laboratory maintained culture of CB782 for nodulation and nitrogen fixation. Both isolates and the original strain were equally effective in N-fixation and all three increased plant dry weight, per cent plants with effective (pink) nodules and amount of nitrogen fixed compared with an uninoculated control. Increasing the level of seed application of inoculum up to the normal rate increased effective nodulation, but excess inoculum levels resulted only in greater numbers of smaller effective (pink) nodules without any increase in nodule dry weight. High inoculum levels decreased the number of white and green nodules compared with the control. Over 50 per cent effective nodulation was obtained with less than 50 Rhizobium seed-1 at sowing. Serological identification and effectiveness tests of strains in nodules confirmed that most white and green nodules on T. semipilosum resulted from infection by naturally occurring white clover rhizobia. These were ineffective in nitrogen fixation with T. semipilosum but fully effective on T. repens. Serological typing of nodules also indicated that normal levels of inoculation resulted in more than 80 per cent of nodules being formed by the specific inoculum strain. We conclude that field sowings of T. semipilosum can be effectively nodulated by the specific inoculum strain CB782 which is both effective and persistent under south-east Queensland conditions. We suggest that most reported nitrogen deficiency symptoms of establishing T. semipilosum are due to infection by Rugose Leaf Curl Virus.

Effect of soil moisture on nodulation of cowpea and hyacinth bean

1976 ◽  
Vol 86 (3) ◽  
pp. 553-560 ◽  
Author(s):  
H. A. Habish ◽  
A. A. Mahdi
Keyword(s):  
Nitrogen Fixation ◽  
Soil Moisture ◽  
Plant Growth ◽  
Dry Weight ◽  
Field Conditions ◽  
Pot Experiments ◽  
Irrigation Interval ◽  
Dry Conditions ◽  
Hyacinth Bean

SummaryPot experiments in which cowpea and hyacinth bean were grown at 15–45% soil moisture showed that nodulation, nitrogen fixation and plant growth were poor at 15%. The weights of nodules and plants were lower in January (winter) than in June (summer). In June cowpea was more tolerant of dry conditions giving good nodulation at 25–35% whereas hyacinth bean required 35–45%.Under field conditions the number and dry weight of nodules were affected by the irrigation interval whereas plant growth was affected by the amount of water applied. Applying 75 mm depth of water every 7 days gave the best combination of nodulation and plant growth.

scholarly journals A reduced fraction of plant N derived from atmospheric N (%Ndfa) and reduced rhizobial nifH gene numbers indicate a lower capacity for nitrogen fixation in nodules of white clover exposed to long-term CO<sub>2</sub> enrichment

2013 ◽  
Vol 10 (12) ◽  
pp. 8269-8281 ◽  
Author(s):  
T. Watanabe ◽  
S. Bowatte ◽  
P. C. D. Newton
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
White Clover ◽  
Trifolium Repens ◽  
Nifh Gene ◽  
Shoot Biomass ◽  
N Fixation ◽  
Dna Amount ◽  
Trifolium Repens L ◽  
Nifh Genes

Abstract. Using the δ15N natural abundance method, we found that the fraction of nitrogen derived from atmospheric N (%Ndfa) in field-grown white clover (Trifolium repens L.) plants was significantly lower (72.0% vs. 89.8%, p = 0.047 in a grassland exposed to elevated CO2 for 13 yr using free air carbon dioxide enrichment (FACE). Twelve months later we conducted an experiment to investigate the reasons behind the reduced N fixation. We took cuttings from white clover plants growing in the FACE and established individual plants in a glasshouse using soil from the appropriate ambient or elevated CO2 treatments. The established plants were then transplanted back into their "rings of origin" and sampled over a 6-week period. We used molecular ecological analyses targeting nifH genes and transcripts of rhizobia in symbiosis with white clover (Trifolium repens L.) to understand the potential mechanisms. Shoot biomass was significantly lower in eCO2, but there was no difference in nodule number or mass per plant. The numbers of nifH genes and gene transcripts per nodule were significantly reduced under eCO2, but the ratio of gene to transcript number and the strains of rhizobia present were the same in both treatments. We conclude that the capacity for biological nitrogen fixation was reduced by eCO2 in white clover and was related to the reduced rhizobia numbers in nodules. We discuss the finding of reduced gene number in relation to factors controlling bacteroid DNA amount, which may imply an influence of nitrogen as well as phosphorus.

Nitrogen fixation by Stereocaulon paschale under field conditions

1977 ◽  
Vol 55 (5) ◽  
pp. 585-592 ◽  
Author(s):  
Kerstin Huss-Danell
Keyword(s):  
Nitrogen Fixation ◽  
Water Content ◽  
Dry Weight ◽  
Field Studies ◽  
Field Conditions ◽  
Dwarf Shrub ◽  
Northern Sweden ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity ◽  
The Mean

Nitrogen fixation (C2H2 reduction) by the lichen Stereocaulon paschale (L.) Fr. was studied in the field in northern Sweden. Field studies were carried out in a very dry dwarf-shrub-type pine forest with S. paschale as the only nitrogen-fixing lichen species. During May–September 1973 and 1974 nitrogen fixation was measured on 28 occasions at irregular intervals, and a total of about 1200 lichen samples were studied. The mean nitrogen-fixation activity during May–September was 0.85 and 1.04 μg N g−1 dry weight h−1 for 1973 and 1974 respectively. The water content of the thallus was the most important factor influencing the nitrogen-fixation activity. Studies on gain and loss of thallus water served as a basis for calculating the number of hours when nitrogen fixation occurred. In the area investigated, with S. paschale covering 14% of the ground, the species was calculated to contribute 0.1 g nitrogen fixed per square metre during May–September 1974.

Annual nitrogen fixation in grazed dairy pastures in south-western Victoria

1999 ◽  
Vol 50 (2) ◽  
pp. 273 ◽  
Author(s):  
Penny A. Riffkin ◽  
Paul E. Quigley ◽  
Fiona J. Cameron ◽  
Mark B. Peoples ◽  
Janice E. Thies
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Dry Matter ◽  
Experimental Studies ◽  
15N Natural Abundance ◽  
N Fixation ◽  
Botanical Composition ◽  
Fixed Nitrogen ◽  
Western Victoria ◽  
On Farm

Amounts of biologically fixed nitrogen (kg N/ha) were determined in grazed dairy pastures in 3 different areas of south-western Victoria over 12 months between October 1995 and 1996 using measurements of pasture growth, botanical composition, and the 15N natural abundance of white clover (Trifolium repens) and non-legume components. Estimates of the amounts of N fixed, based on N in clover shoots, were similar in each pasture (11, 16, and 18 kg N/ha.year), despite different environmental and management conditions. These on-farm determinations were low compared with experimental studies on N fixation by white clover undertaken in New Zealand (224–291 kg N/ha.year) and elsewhere in Australia (44–135 kg N/ha). Low fixation levels were attributed to low pasture yields (average 8.2 t dry matter (DM)/ha.year) and poor legume content in the swards (average 8%). Despite this, most of the white clover N was derived from atmospheric N2 (65%), and therefore, N fixation could potentially be playing an important role in the N economy of milk production on these farms.

Increasing biological nitrogen fixation by white clover-rhizobia symbiosis

2019 ◽  
pp. 231-234 ◽  
Author(s):  
Shengjing Shi ◽  
Laura Villamizar ◽  
Emily Gerard ◽  
Clive Ronson ◽  
Steve Wakelin ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Biological Nitrogen Fixation ◽  
Root Nodules ◽  
N Fixation ◽  
Nodule Occupancy ◽  
Coating Technology ◽  
Vitro Assay ◽  
Biological Nitrogen

Biological nitrogen fixation (BNF) is the process of converting atmospheric nitrogen to ammonia through legume–rhizobia symbiosis. The nitrogen fixed by rhizobia in root nodules is available for plant use. This process can be harnessed to improve N fertility on farm. Field surveys across New Zealand (NZ), within a farm and within paddocks, have revealed large spatial variability of rhizobial population size and symbiotic effectiveness with white clover. These results indicate that naturalised rhizobia may not be supporting optimal BNF. Over 500 strains of clover-nodulating rhizobia were isolated from NZ pasture soils, with more than 90 demonstrating greater N-fixation capacity with white clover than the commercial inoculant strain TA1. Seven NZ isolates were tested for nodule occupancy and all seven had significantly higher occupancy rates than TA1 in an in vitro assay, indicating increased competitiveness of those strains. In addition, novel seed-coating technology improved the survival of TA1 and isolate S10N9 from 1 month to more than 4 months compared with a standard coating formulation. There is potential to increase the symbiotic capacity of white clover in pastures through use of more effective and competitive rhizobial strains, along with their improved survival on seed provided by a new coating technology.

The Effects of Irrigation, Inoculants and Fertilizer Nitrogen on Peanuts (Arachis hypogaea L.). I. Nitrogen Fixation

1980 ◽  
Vol 7 (2) ◽  
pp. 114-119 ◽  
Author(s):  
V. M. Reddy ◽  
J. W. Tanner
Keyword(s):  
Nitrogen Fixation ◽  
Arachis Hypogaea ◽  
Dry Weight ◽  
N Fixation ◽  
Nitrogen Application ◽  
Fertilizer Nitrogen ◽  
Nodule Number ◽  
Arachis Hypogaea L ◽  
Different Strains

Abstract Effects of irrigation, inoculants and fertilizer nitrogen (N) on N2(C2H2) fixation in peanuts were studied in 1976 and 1977 at Delhi, Ontario. Inoculant application increased nodulation and N-fixation in both years. Powdered peat and granular formulations containing the same strains of rhizobia resulted in almost the same amounts of nodulation and N-fixation (80 kg/ha on average). Differences in nodulation from inoculants containing different strains of rhizobia were not consistent over the two years. However, 60% difference in N-fixation resulted from the inoculants containing different strains of rhizobia in both years. Nitrogen application decreased the nodule number, nodule dry weight, and N-fixation of all the inoculated peanuts. Irrigation increased the N-fixation of the peanuts treated with granular inoculant in 1976 by an average of 45% and all the inoculated peanuts in 1977 by an average of 54% but had no effect on nodulation in either year.

scholarly journals A reduced fraction of plant N derived from atmospheric N (%Ndfa) and reduced rhizobial nifH gene numbers indicate a lower capacity for nitrogen fixation in nodules of white clover exposed to long-term CO<sub>2</sub> enrichment

2013 ◽  
Vol 10 (6) ◽  
pp. 9867-9896 ◽  
Author(s):  
T. Watanabe ◽  
S. Bowatte ◽  
P. C. D. Newton
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
White Clover ◽  
Trifolium Repens ◽  
Nifh Gene ◽  
Shoot Biomass ◽  
N Fixation ◽  
Dna Amount ◽  
Trifolium Repens L ◽  
Nifh Genes

Abstract. Using the δ15N natural abundance method, we found that the fraction of nitrogen derived from atmospheric N (%Ndfa) in field grown white clover (Trifolium repens L.) plants was significantly lower (72.0% vs. 89.5%, p = 0.047 in a grassland exposed to elevated CO2 for 13 yr using Free Air Carbon Dioxide Enrichment (FACE). Twelve months later we conducted an experiment to investigate the reasons behind the reduced N fixation. We took cuttings from white clover plants growing in the FACE and established individual plants in a glasshouse using soil from the appropriate ambient or elevated CO2 treatments. The established plants were then transplanted back into their "rings of origin" and sampled over a 6 week period. We used molecular ecological analyses targeting nifH genes and transcripts of rhizobia in symbiosis with white clover (Trifolium repens L.) to understand the potential mechanisms. Shoot biomass was significantly lower in eCO2 but there was no difference in nodule number or mass per plant. The numbers of nifH genes and gene transcripts per nodule were significantly reduced under eCO2 but the ratio of gene to transcript number and the strains of rhizobia present were the same in both treatments. We conclude that the capacity for biological nitrogen fixation was reduced by eCO2 in white clover and was related to the reduced rhizobia numbers in nodules. We discuss the finding of reduced gene number in relation to factors controlling bacteroid DNA amount which may imply an influence of nitrogen as well as phosphorus.

Asymbiotic nitrogen fixation in litter from Pacific Northwest forests

1988 ◽  
Vol 18 (1) ◽  
pp. 68-74 ◽  
Author(s):  
B. Heath ◽  
P. Sollins ◽  
D.A. Perry ◽  
K. Cromack Jr.
Keyword(s):  
Nitrogen Fixation ◽  
C:N Ratio ◽  
Dry Weight ◽  
Weight Percent ◽  
Douglas Fir ◽  
The Other ◽  
N Fixation ◽  
Litter Layer ◽  
Willamette Valley ◽  
Asymbiotic Nitrogen Fixation

Asymbiotic nitrogen fixation in litter was assayed by acetylene reduction across a range of 25 forested sites in the Willamette Valley and Oregon Cascade and Coast ranges and periodically over a year at two Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantations in the Willamette Valley. Laboratory experiments showed that optimal conditions for N fixation by Douglas-fir litter were 200% moisture content and 22 °C. Annual fixation was 1.08 ± 0.13 kg/ha at one Willamette Valley plantation, 0.39 ± 0.06 kg/ha at the other. Fixation rates at the other 23 sites, which were sampled less frequently, ranged from 0 to 5 g N ha−1 day−1 and exceeded trace levels at only six sites, indicating annual totals much less than those at the Willamette Valley plantations. At four coastal and valley sites sampled by litter layer, older L layer Douglas-fir litter fixed the most N per gram dry weight. Percent N, percent C, and the C:N ratio of that litter layer did not differ significantly among sites or correlate with N-fixation rates. Forest-floor litter in most Northwest forests fixes no more than trace amounts of N, at most ~1 kg N ha−1 year−1. These amounts are smaller than N input from precipitation.

scholarly journals Nitrogen fixation by subterranean and white clovers in dryland cocksfoot pastures

2010 ◽  
pp. 141-146 ◽  
Author(s):  
R.J. Lucas ◽  
M.C. Smith ◽  
P. Jarvis ◽  
A. Mills ◽  
D.J. Moot
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
Dry Matter ◽  
N Fixation ◽  
Grazing Experiment ◽  
Enrichment Technique ◽  
15N Enrichment ◽  
Lincoln University

The amount of nitrogen (N) in clover dry matter (DM) herbage derived from N fixation in subterranean or white clover was estimated using the 15N enrichment technique in a dryland grazing experiment at Lincoln University.

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