Distribution, abundance and symbiotic effectiveness of Rhizobium leguminosarum bv. trifolii from alkaline pasture soils in South Australia

2000 ◽  
Vol 40 (1) ◽  
pp. 25 ◽  
Author(s):  
M. D. Denton ◽  
D. R. Coventry ◽  
W. D. Bellotti ◽  
J. G. Howieson
Keyword(s):  
N2 Fixation ◽  
Rhizobium Leguminosarum ◽  
South Australia ◽  
Shoot Biomass ◽  
Alkaline Soil ◽  
Symbiotic Effectiveness ◽  
Management Options ◽  
Soil Constraints ◽  
Reference Strains ◽  
Rhizobial Population

The current dissatisfaction with low productivity of annual medic (Medicago spp.) pastures has highlighted the need to seek alternative legumes to provide efficient N2 fixation in low rainfall, alkaline soil environments of southern Australia. Clover species adapted to these environments will have limited N2 fixation if effective rhizobia are not present in sufficient quantities. A survey of 61 sites was conducted across South Australia to determine the size, distribution and effectiveness of Rhizobium leguminosarum bv. trifolii (clover rhizobia) populations resident in these low rainfall, alkaline soil environments. Clover rhizobia were detected at 56 of the sites, with a median density of 230–920 rhizobia/g soil. Most rhizobial populations were poor in their capacity to fix nitrogen. Rhizobial populations from fields provided 11–89% and 10–85% of the shoot biomass of commercial reference strains when inoculated onto host legumes T. purpureum (purple clover) and T. resupinatum (persian clover), respectively. Rhizobial population size was correlated negatively to pH and the percentage of CaCO3 in the soil, and was significantly increased in the rhizospheres of naturalised clover, found at 17 sites. Management options for rhizobial populations to improve legume diversity and productivity are discussed in terms of rhizobial population dynamics and likely soil constraints to successful rhizobial colonisation.

Nitrogen fixation in annual Trifolium species in alkaline soils as assessed by the 15N natural abundance method

2011 ◽  
Vol 62 (8) ◽  
pp. 712 ◽  
Author(s):  
Matthew D. Denton ◽  
David R. Coventry ◽  
William D. Bellotti ◽  
John G. Howieson
Keyword(s):  
N2 Fixation ◽  
Rhizobium Leguminosarum ◽  
Farming Systems ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Soil Conditions ◽  
Nodule Occupancy ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Mixed Farming

Annual clover species such as Trifolium purpureum Loisel., T. resupinatum L., and T. alexandrinum L. are adapted to alkaline soil conditions and provide certain agronomic advantages over annual medics (Medicago spp.). Annual clovers have not been widely grown in alkaline soils in Australia, and quantifying their dinitrogen (N2) fixation in alkaline soils is important in understanding their potential role in mixed farming systems of southern Australia. Using the 15N natural abundance technique, it was estimated that annual clovers fixed 101–137 kg N/ha at Roseworthy and 59–62 kg N/ha at Mallala, on Calcarosols with soil pH of 8.0 and 8.5, respectively. Species differed in the percentages of fixed N2 estimated in shoot dry matter, which was highest in T. alexandrinum (77–85%), moderate in T. resupinatum (76%), and lowest in T. purpureum (65–74%). Naturally occurring soil rhizobia (Rhizobium leguminosarum bv. trifolii) provided adequate nodulation, as inoculation with different strains of rhizobia had little influence on nodulation or N2 fixation. These results indicate that clovers can provide a significant contribution of fixed N2 to mixed farming systems. Examination of nodules indicated variable nodule occupancy by the inoculant rhizobia and that 69% of shoot N was fixed when clovers were nodulated by the soil populations of rhizobia. A simple model is defined to identify the potential interactions between inoculated legumes and soil rhizobia, and the options for enhancing symbiotic effectiveness are discussed.

Nitrogen fixation characteristics of Rhizobium surviving in soils 'equilibrated' with sewage biosolids

2001 ◽  
Vol 52 (10) ◽  
pp. 963 ◽  
Author(s):  
Kellie J. Munn ◽  
Jeffrey Evans ◽  
Phillip M. Chalk
Keyword(s):  
N2 Fixation ◽  
Soil Type ◽  
Rhizobium Leguminosarum ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Subterranean Clover ◽  
Isotope Dilution Method ◽  
Dilution Method ◽  
Symbiotic Effectiveness ◽  
Amended Soils

To determine the effects of urban sewage biosolids on the symbiotic effectiveness of Rhizobium leguminosarum bv. trifolii and N2 fixation, glasshouse and laboratory studies were carried out with several soils, biosolids, and biosolid application levels. Symbiotic effectiveness of R. l. trifolii was estimated as the dry weight or N content of seedlings of subterranean clover grown with only N2 fixation and seed N as the available nitrogen sources. The N fixed by legumes in unamended and biosolid-amended soils was determined using the 15N isotope dilution method. Six soils were represented in the experiments. Each of these was equilibrated over a period of 12 months with dried, finely ground biosolids (DWS) from the Malabar sewage treatment plant, at biosolids levels ranging from the equivalent of 60 to 240 t DWS/ha. One of the soils was also equilibrated with each of 4 other biosolids. The maximal concentration of heavy metals in soil amended with biosolids was 1026 mg/kg. The effect of biosolids on symbiotic effectiveness depended on the soil type and biosolid applications level. Thus, biosolids reduced the symbiotic effectiveness of R. l. trifolii in 2 of the 6 soils, although at different levels of biosolid. In most soil treatments N2 fixation was detected in subterranean clover, confirming the persistence of symbiotically effective rhizobia in most biosolids-amended soils. In addition, in strongly acidic soils plant N and N2 fixation increased significantly with biosolids addition, probably in response to higher soil pH, exchangeable Ca, and available P. In the treatments in which the symbiotic effectiveness of R. l. trifolii was reduced by biosolids, this was reflected in poor N2 fixation. However, symbiotic effectiveness did not correlate well with N2 fixation, probably because increases in soil nitrate at higher biosolids levels inhibited N2 fixation. Nevertheless, there were instances at 240 t DWS/ha where this was unlikely to explain the decrease in N2 fixation. It was concluded that adverse effects of biosolids on symbiotic effectiveness depend first on soil type, and then on biosolid type and application level; and the response in symbiotic effectiveness to adding biosolids to soil needs to be determined for each distinctively different site of biosolids reuse.

Competition between inoculant and naturalised Rhizobium leguminosarum bv. trifolii for nodulation of annual clovers in alkaline soils

2002 ◽  
Vol 53 (9) ◽  
pp. 1019 ◽  
Author(s):  
M. D. Denton ◽  
D. R. Coventry ◽  
P. J. Murphy ◽  
J. G. Howieson ◽  
W. D. Bellotti
Keyword(s):  
Rhizobium Leguminosarum ◽  
South Australia ◽  
First Year ◽  
Nodule Occupancy ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Field Site ◽  
Chain Reaction ◽  
Edaphic Conditions ◽  
Polymerase Chain

Inoculant rhizobia typically need to compete with naturalised soil populations of rhizobia to form legume nodules. We have used the polymerase chain reaction to test the ability of seed-inoculated rhizobia to compete with naturalised populations of rhizobia and form nodules on clover (Trifolium alexandrinum, T.�purpureum, and T. resupinatum) in alkaline soil. Clover rhizobia, Rhizobium leguminosarum bv. trifolii, were identified at the strain level using either a nif-specific RP01 primer or ERIC primers. Analysis of rhizobia isolated from nodules indicated that strain TA1 competed poorly for nodule occupancy at 2 field sites (Roseworthy and Mallala, South Australia), with the exception that it nodulated T. alexandrinum at a level of 39% at the Roseworthy site in the first year of the trial. Strains CC2483g and WSM409 successfully colonised nodules when inoculated onto a particular clover species (T. resupinatum and T. purpureum, respectively) in the first year of inoculation and persisted in the soil to form nodules in the following year. Nodules frequently contained naturalised strains of rhizobia, distinct from introduced commercial strains. Dominant isolates were specific to a field site and nodulated all 3 clover species in both years of the field trial, with each isolate occupying up to 19% of the total nodules at a field site. It was hypothesised that field isolates had a better alkaline soil tolerance conferring a greater ability to nodulate clovers under these edaphic conditions. The results indicate that soil populations of rhizobia may provide a significant constraint to the introduction of current Australian commercial clover rhizobia into alkaline soils, and a more profitable strategy may be to seek rhizobial inoculants that are adapted to these soils.

Symbiotic effectiveness and bacteriocin production by Rhizobium leguminosarum bv. viciae isolated from agriculture soils in Faisalabad

2005 ◽  
Vol 54 (2) ◽  
pp. 142-147 ◽  
Author(s):  
Fauzia Y. Hafeez ◽  
Farrukh I. Naeem ◽  
Rehan Naeem ◽  
Arsalan H. Zaidi ◽  
Kausar A. Malik
Keyword(s):  
Rhizobium Leguminosarum ◽  
Bacteriocin Production ◽  
Symbiotic Effectiveness

scholarly journals Microbial Consortium of PGPR, Rhizobia and Arbuscular Mycorrhizal Fungus Makes Pea Mutant SGECdt Comparable with Indian Mustard in Cadmium Tolerance and Accumulation

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 975 ◽  
Author(s):  
Andrey A. Belimov ◽  
Alexander I. Shaposhnikov ◽  
Tatiana S. Azarova ◽  
Natalia M. Makarova ◽  
Vera I. Safronova ◽  
...  
Keyword(s):  
Plant Growth ◽  
Rhizobium Leguminosarum ◽  
Microbial Consortium ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Indian Mustard ◽  
Arbuscular Mycorrhizal ◽  
Shoot Biomass ◽  
Acetylene Reduction Activity ◽  
Nodule Bacterium

Cadmium (Cd) is one of the most widespread and toxic soil pollutants that inhibits plant growth and microbial activity. Polluted soils can be remediated using plants that either accumulate metals (phytoextraction) or convert them to biologically inaccessible forms (phytostabilization). The phytoremediation potential of a symbiotic system comprising the Cd-tolerant pea (Pisum sativum L.) mutant SGECdt and selected Cd-tolerant microorganisms, such as plant growth-promoting rhizobacterium Variovorax paradoxus 5C-2, nodule bacterium Rhizobium leguminosarum bv. viciae RCAM1066, and arbuscular mycorrhizal fungus Glomus sp. 1Fo, was evaluated in comparison with wild-type pea SGE and the Cd-accumulating plant Indian mustard (Brassica juncea L. Czern.) VIR263. Plants were grown in pots in sterilized uncontaminated or Cd-supplemented (15 mg Cd kg−1) soil and inoculated or not with the microbial consortium. Cadmium significantly inhibited growth of uninoculated and particularly inoculated SGE plants, but had no effect on SGECdt and decreased shoot biomass of B. juncea. Inoculation with the microbial consortium more than doubled pea biomass (both genotypes) irrespective of Cd contamination, but had little effect on B. juncea biomass. Cadmium decreased nodule number and acetylene reduction activity of SGE by 5.6 and 10.8 times, whereas this decrease in SGECdt was 2.1 and 2.8 times only, and the frequency of mycorrhizal structures decreased only in SGE roots. Inoculation decreased shoot Cd concentration and increased seed Cd concentration of both pea genotypes, but had little effect on Cd concentration of B. juncea. Inoculation also significantly increased concentration and/or accumulation of nutrients (Ca, Fe, K, Mg, Mn, N, P, S, and Zn) by Cd-treated pea plants, particularly by the SGECdt mutant. Shoot Cd concentration of SGECdt was twice that of SGE, and the inoculated SGECdt had approximately similar Cd accumulation capacity as compared with B. juncea. Thus, plant–microbe systems based on Cd-tolerant micro-symbionts and plant genotypes offer considerable opportunities to increase plant HM tolerance and accumulation.

Nitrogen fixation by subterranean clover (Trifolium subterraneum L.) growing in pure culture and in mixtures with varying densities of lucerne (Medicago sativa L.) or phalaris (Phalaris aquatica L.)

1999 ◽  
Vol 50 (6) ◽  
pp. 1047 ◽  
Author(s):  
B. S. Dear ◽  
M. B. Peoples ◽  
P. S. Cocks ◽  
A. D. Swan ◽  
A. B. Smith
Keyword(s):  
Medicago Sativa ◽  
N2 Fixation ◽  
Pure Culture ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Shoot Biomass ◽  
N Fixation ◽  
Mineral N ◽  
Phalaris Aquatica ◽  
Medicago Sativa L

The proportions of biologically fixed (Pfix) plant nitrogen (N) and the total amounts of N2 fixed by subterranean clover (Trifolium subterraneum L.) growing in pure culture and in mixtures with different densities (5, 10, 20, or 40plants/m2) of newly sown phalaris (Phalaris aquatica L.) or lucerne (Medicago sativa L.) were followed over 3 years in a field study using the 15N natural abundance technique. The amount of fixed N in subterranean clover was linearly related to shoot biomass. Over the 3-year period, subterranean clover fixed 23–34 kg N/t shoot biomass compared with 17–29 kg N/t shoot biomass in lucerne. Based on above-ground biomass, pure subterranean clover fixed 314 kg N/ha over the 3 years compared with 420–510 kg N/ha by lucerne–clover mixtures and 143–177 kg N/ha by phalaris–clover mixtures. The superior N2 fixation by the lucerneŒsubterranean clover mixtures was due to the N fixed by the lucerne and the presence of a higher subterranean clover biomass relative to that occurring in the adjacent phalaris plots. In the first year, 92% of subterranean clover shoot N was derived from fixation compared with only 59% of lucerne. The reliance of clover upon fixed N2 remained high (73–95%) throughout the 3 years in all swards, except in pure subterranean clover and lucerne in August 1996 (56 and 64%, respectively). Subterranean clover usually fixed a higher proportion of its N when grown in mixtures with phalaris than with lucerne. The calculated Pfix values for lucerne (47–61% in 1995 and 39–52% in 1996) were consistently lower than in subterranean clover and tended to increase with lucerne density. Although lucerne derived a lower proportion of its N from fixation than subterranean clover, its tissue N concentration was consistently higher, indicating it was effective at scavenging soil mineral N. It was concluded that including lucerne in wheat-belt pastures will increase inputs of fixed N. Although lucerne decreased subterranean clover biomass, it maintained or raised Pfix values compared with pure subterranean clover swards. The presence of phalaris maintained a high dependence on N2 fixation by subterranean clover, but overall these swards fixed less N due to the lower clover herbage yields. Perennial and annual legumes appear compatible if sown in a mix and can contribute more N2 to the system than where the annual is sown alone or with a perennial grass. These findings suggest that increases in the amount of N2 fixed can be achieved through different legume combinations without interfering greatly with the N fixation process. Different combinations may also result in more efficient use of fixed N2 through reduced leaching. Further work looking at combinations of annuals possibly with different maturity times, different annual and perennial legume combinations, and pure combinations of perennial (e.g. lucerne) could be investigated with the aim of maximising N2 fixation and use. Grazing management to encourage clover production in mixtures with phalaris will be necessary before the potential of subterranean clover to contribute fixed N2 in these swards is fully realised.

Symbiotic effectiveness of Rhizobium leguminosarum bv. trifolii collected from pastures in south-western Victoria

1997 ◽  
Vol 37 (6) ◽  
pp. 623 ◽  
Author(s):  
P. E. Quigley ◽  
P. J. Cunningham ◽  
M. Hannah ◽  
G. N. Ward ◽  
T. Morgan
Keyword(s):  
Rhizobium Leguminosarum ◽  
Subterranean Clover ◽  
Annual Rainfall ◽  
Test Plant ◽  
Available Phosphorus ◽  
Symbiotic Effectiveness ◽  
Plant Weight ◽  
Commercial Inoculant ◽  
Shoot Weight ◽  
Western Victoria

Summary. The whole-soil inoculation method was used to assess the symbiotic effectiveness of rhizobia populations in soils collected from 18 randomly-selected pastures in south-western Victoria. This was part of a larger study which described the condition of pasture within this region. Based on the shoot weights of test subterranean clover plants, cv. Mount Barker, effectiveness varied from 36 to 94% depending on the site of rhizobia collection. This range was wider than that found in an earlier survey of rhizobia effectiveness conducted nearby. WU95, the commercial inoculant for subterranean clover, was significantly more effective than 9 of the rhizobia samples. Rhizobia from 2 sites were especially poor and their effectiveness (37%) was not significantly different from the nil inoculum control (28%). Symbiotic effectiveness was not related to soil pH, available sulfur, available phosphorus, total nitrogen or mean annual rainfall for each site where rhizobia were collected. After pooling data for all sites, the shoot weights were significantly related to the proportions of plants with nodules assigned high nodulation scores. In contrast, low scores, within 1 of 6 categories, did not significantly affect shoot weight. The technique of using mean nodulation score was less capable of discriminating differences in symbiotic effectiveness, compared with assessment based on test plant weight.

Electromagnetic induction sensing of soil identifies constraints to the crop yields of north-eastern Australia

Soil Research ◽  
2011 ◽  
Vol 49 (7) ◽  
pp. 559 ◽  
Author(s):  
Y. P. Dang ◽  
R. C. Dalal ◽  
M. J. Pringle ◽  
A. J. W. Biggs ◽  
S. Darr ◽  
...  
Keyword(s):  
Grain Yield ◽  
Electromagnetic Induction ◽  
Crop Production ◽  
Crop Yields ◽  
Yield Potential ◽  
Management Options ◽  
Soil Constraints ◽  
Eastern Australia ◽  
North Eastern ◽  
On Farm

Salinity, sodicity, acidity, and phytotoxic concentrations of chloride (Cl–) in soil are major constraints to crop production in many soils of north-eastern Australia. Soil constraints vary both spatially across the landscape and vertically within the soil profile. Identification of the spatial variability of these constraints will allow farmers to tune management to the potential of the land, which will, in turn, bring economic benefit. For three cropping fields in Australia’s northern grains region, we used electromagnetic induction with an EM38, which measures apparent electrical conductivity of the soil (ECa) and soil sampling to identify potential management classes. Soil Cl– and soluble Na+ concentrations, EC of the saturated extract (ECse), and soil moisture were the principal determinants of the variation of ECa, measured both at the drained upper limit of moisture (UL) and at the lower limit (LL) of moisture extracted by the crop. Grain yield showed a strong negative relation with ECa at both UL and LL, although it was stronger for the latter. We arrive at a framework to estimate the monetary value of site-specific management options, through: (i) identification of potential management classes formed from ECa at LL; (ii) measurement of soil attributes generally associated with soil constraints in the region; (iii) grain yield monitoring; and (iv) simple on-farm experiments. Simple on-farm experiments suggested that, for constrained areas, matching fertiliser application to realistic yield potential, coupled to gypsum amelioration, could potentially benefit growers by AU$14–46/ha.year (fertiliser) and $207/ha.3 years (gypsum).

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