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.

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.

scholarly journals Bradyrhizobium strain and the 15N natural abundance quantification of biological N2 fixation in soybean

2008 ◽  
Vol 65 (5) ◽  
pp. 516-524 ◽  
Author(s):  
Ana Paula Guimarães ◽  
Rafael Fiusa de Morais ◽  
Segundo Urquiaga ◽  
Robert Michael Boddey ◽  
Bruno José Rodrigues Alves
Keyword(s):  
N2 Fixation ◽  
B Value ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Soil Conditions ◽  
Total N ◽  
Biological N2 Fixation ◽  
Bradyrhizobium Strain ◽  
Shoot Tissue ◽  
Biological Nitrogen

In commercial plantations of soybean in both the Southern and the Cerrado regions, contributions from biological nitrogen fixation (BNF) are generally proportionately high. When using the 15N natural abundance technique to quantify BNF inputs, it is essential to determine, with accuracy, the 15N abundance of the N derived from BNF (the 'B' value). This study aimed to determine the effect of four recommended strains of Bradyrhizobium spp. (two B. japonicum and two B. elkanii) on the 'B' value of soybean grown in pots in an open field using an equation based on the determination of δ15N natural abundance in a non-labelled soil, and estimate of the contribution of BNF derived from the use of 15N-isotope dilution in soils enriched with 15N. To evaluate N2 fixation by soybean, three non-N2-fixing reference crops were grown under the same conditions. Regardless of Bradyrhizobium strain, no differences were observed in dry matter, nodule weight and total N between labelled and non-labelled soil. The N2 fixation of the soybeans grown in the two soil conditions were similar. The mean 'B' values of the soybeans inoculated with the B. japonicum strains were -1.84 ‰ and -0.50 ‰, while those inoculated with B. elkanii were -3.67 ‰ and -1.0 ‰, for the shoot tissue and the whole plant, respectively. Finally, the 'B' value for the soybean crop varied considerably in function of the inoculated Bradyrhizobium strain, being most important when only the shoot tissue was utilised to estimate the proportion of N in the plant derived from N2 fixation.

Nitrogen fixation by irrigated lucerne during the first three years after establishment

1995 ◽  
Vol 46 (7) ◽  
pp. 1401 ◽  
Author(s):  
RR Gault ◽  
MB Peoples ◽  
GL Turner ◽  
DM Lilley ◽  
J Brockwell ◽  
...  
Keyword(s):  
Soil Nitrogen ◽  
N2 Fixation ◽  
Dry Matter ◽  
Growing Season ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Dry Matter Production ◽  
Available Phosphorus ◽  
The Third ◽  
Matter Production

Nodulation, N2 fixation (estimated by 15N natural abundance methods) and dry matter production were studied in a lucerne (Medicago sativa) crop managed for hay production at Ginninderra Experiment Station, A.C .T. Measurements were taken in the year of establishment and during two subsequent growing seasons. There were three treatments: (1) no inoculation and no annual fertilizer applied, (2) initial inoculation and superphosphate applied annually, (3) no inoculation, superphosphate applied annually and ammonium sulfate periodically. Before planting and after each growth season, soil was analysed for extractable mineral nitrogen, total nitrogen and the 15N natural abundance of this nitrogen, to the depth explored by lucerne roots. Before planting, no appropriate root-nodule bacteria (Rhizobium meliloti) were detected in the soil and initially plants were nodulated only in the inoculated treatment. Thereafter nodulation increased on the other treatments. Eight months after sowing there were no differences between treatments in numbers of R. meliloti g-l soil or in nodulation. In the third growing season, almost 30 kg ha-1 (dry wt) of nodules were recovered to a depth of 25 cm. These nodules were primarily located on fine, ephemeral roots and many appeared to be renewed after cutting of the lucerne. In the year of establishment, dry matter yields (0% moisture) totalled 3 to 4 t ha-1 in three hay cuts. In succeeding years, total yields were in the range 10 to 13 t ha-1 in four or five cuts per season. Nitrogen removed in the harvested lucerne reached 340 to 410 kg N ha-lyr-l in the second and third years and between 65 and 96% of this N arose from N2 fixation, depending on the method of calculation used. Poorer dry matter production and N2 fixation in treatment 1 in the third growing season was attributed to an insufficient supply of available phosphorus. Fixed N removed in Lucerne hay from treatment 2 totalled at least 640 kg N ha-1 in the three years of the experiment. Also, there were substantial increases in soil nitrogen due to lucerne growth. Although soil compaction made the quantification difficult, at the end of the experiment it was estimated that there was at least an extra 800 kg N ha-1 in the total soil nitrogen under lucerne compared to strips of Phalaris aquatica grown between the lucerne plots. It was concluded that lucerne contributed at least the same amount of fixed nitrogen to the soil as was being removed in the harvested hay.

Nitrogen fixation in chickpea. II. Comparison of 15N enrichment and 15N natural abundance methods for estimating nitrogen fixation

1995 ◽  
Vol 46 (1) ◽  
pp. 225 ◽  
Author(s):  
JA Doughton ◽  
PG Saffigna ◽  
I Vallis ◽  
RJ Mayer
Keyword(s):  
Nitrogen Fixation ◽  
N2 Fixation ◽  
Full Range ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Enrichment Method ◽  
Mineral N ◽  
Crop Establishment ◽  
15N Enrichment ◽  
15N Natural Abundance Method

The 15N enrichment and 15N natural abundance methods for estimating N2 fixation in chickpea were compared over a range of soil NO3-N levels at crop establishment varying from 10 to 326 kg N/ha (0-120 cm depth). Barley was used as a non-N2 fixing control crop. Both methods estimated reduced N2 fixation as soil NO3-N levels at crop establishment increased. Similar estimates of % N2 fixation were obtained at high values, but at low values the enrichment method gave lower estimates, some of which were negative. The 15N natural abundance method provided realistic estimates of % N2 fixation across all soil N03-N levels at crop establishment. An asymptotic curve described a close ( R2 = 0.95) relationship between these factors. Standard errors of estimates of means for the 15N natural abundance method remained acceptable and relatively stable over the full range of measurements; however, with the 15N enrichment method they became unacceptably large at low values of % N2 fixation. These large errors may have been partly due to legume and control plants assimilating mineral N of differing 15N enrichment. High mineral N levels associated with low values of % N2 fixation were also shown to reduce reliability of N2 fixation values estimated by the 15N enrichment method. These errors caused potentially greater inaccuracy at low values of % N2 fixation than at high values. To compare N2 fixation means statistically, transformations were necessary to stabilize variance and to impart lower weightings to plots with low values of % N2 fixation.

scholarly journals Field Screening of Cowpea Genotypes for Alkaline Soil Tolerance

HortScience ◽  
2010 ◽  
Vol 45 (11) ◽  
pp. 1639-1642 ◽  
Author(s):  
Ricardo Goenaga ◽  
A. Graves Gillaspie ◽  
Adolfo Quiles
Keyword(s):  
Field Experiments ◽  
Virgin Islands ◽  
Growth And Yield ◽  
Soil Conditions ◽  
Yield Reduction ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Legume Crop ◽  
Yield Production ◽  
Leaf Chlorosis

Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable, and for consumption of its dry beans, which provide 22% to 25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowpea develops severe leaf chlorosis caused by deficiencies of iron (Fe), zinc (Zn), and manganese (Mn) resulting in stunted plant growth and yield reduction. We evaluated in replicated field experiments at St. Croix, U.S. Virgin Islands, and Juana Díaz, Puerto Rico, 24 PIs and two commercial cultivars, some of which have shown some tolerance to alkaline soils in unreplicated, seed regeneration plots of the U.S. cowpea collection. Alkaline soil conditions at St. Croix were too severe resulting in average yield of genotypes at this location being significantly lower and 77% less than that at Juana Díaz. Nevertheless, some genotypes performed well at both locations. For example, PIs 222756, 214354, 163142, 582605, 582840, 255766, 582610, 582614, 582576, 582809, and 349674 yielded in the upper half of the group at both locations. Accession PI 163142 ranked third in grain yield production at both locations and outyielded the iron-chlorosis-resistant controls at St. Croix. These genotypes deserve further attention as potential sources of alkaline soil tolerance.

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