A FOUR-YEAR QUANTITATIVE STUDY OF NITROGEN-FIXING BACTERIA IN SOILS OF DIFFERENT FERTILIZER TREATMENT

1936 ◽  
Vol 14c (4) ◽  
pp. 166-177 ◽  
Author(s):  
A. G. Lochhead ◽  
R. H. Thexton
Keyword(s):  
Nitrogen Fixation ◽  
Crop Yields ◽  
The Other ◽  
Seasonal Effect ◽  
Fertilizer Treatment ◽  
Rhizobium Trifolii ◽  
Field Soil ◽  
Seasonal Influence ◽  
Plate Method ◽  
Minimum Numbers

Numbers of Rhizobium trifolii, Rh. leguminosarum, Rh. meliloti and Azotobacter were determined at four-week intervals throughout a four-year crop rotation in three soils which had been receiving for twenty years no fertilizer, manure, and artificial fertilizer respectively. Though relatively small differences were noted in numbers of Rh. trifolii in the three soils, Rh. leguminosarum and Rh. meliloti persisted in much higher numbers in the two fertilized areas than in the unfertilized soil. Rh. trifolii, the only species with host plant in the rotation, occurred in much greater numbers than the other species, not only during and immediately following clover, but in succeeding years when little or no decline was noted. Apart from the effect of clover on Rh. trifolii no significant effect of cropping was noted nor was seasonal influence important. Freezing of the soil for three months each year produced little or no effect on the numbers of Rhizobia.Numbers of Azotobacter were consistently higher in the unfertilized soil than in the fertilized areas. A seasonal effect was noted, with maximum numbers in March and minimum numbers in July, while freezing caused no noticeable diminution in colony count. The numbers of Azotobacter found were in all cases low and suggest that the part played by this organism in nitrogen fixation in field soil is still obscure.Rh. trifolii, Azotobacter and total numbers of bacteria by the plate method showed no relation with the productivity of the soils. Numbers of Rh. leguminosarum and Rh. meliloti showed better agreement, though only in the case of Rh. meliloti were relative numbers consistent with the soils in order of crop yields throughout the rotation.

CORRELATION BETWEEN BACTERIAL NUMBERS AND CARBON DIOXIDE IN A FIELD SOIL

1957 ◽  
Vol 3 (2) ◽  
pp. 191-194 ◽  
Author(s):  
P. H. H. Gray ◽  
R. H. Wallace
Keyword(s):  
Carbon Dioxide ◽  
Crop Residues ◽  
Soil Treatment ◽  
Soil Conditions ◽  
Field Soil ◽  
Plate Method

Bacterial numbers, estimated by the plate method, and carbon dioxide were significantly correlated (r = 0.50–0.69) in field soil during 1955, in an experiment designed to test the effects of straw and crop residues on soil conditions. Differences in moisture, temperature, and soil treatment did not interfere with the correlation.

scholarly journals Evaluation of the performance of three advisory methods for nitrogen fertilization of sugar beet and potatoes.

1989 ◽  
Vol 37 (2) ◽  
pp. 143-155 ◽  
Author(s):  
J.J. Neeteson
Keyword(s):  
Crop Yields ◽  
Current Method ◽  
Early Spring ◽  
The Other ◽  
Fertilizer N ◽  
Potato Tubers ◽  
Current Recommendation ◽  
Mineral N ◽  
Fertilizer Recommendation ◽  
The Difference

The performances of 3 different N fertilizer recommendation methods were retrospectively tested with data obtained from 150 trials with sugarbeet and 98 trials with potatoes in the Netherlands in 1973-82. The recommendations consisted of applying a fixed N rate in all situations (126 kg N/ha for sugarbeet and 286 kg N/ha for potatoes), the current Dutch method, which takes only the amount of mineral N present in the soil in early spring into account, and a refinement of the current method, which also takes soil type and recent applications of organic manures into account. On av., significantly lower amounts of fertilizer N were recommended with the current method. The difference from the other methods was on av. 25 kg N/ha for sugarbeet and 30 kg N/ha for potatoes. With the refined current method the highest crop yields were obtained but the difference from the other methods was not significant and averaged only 0.3-0.4 t/ha for sugarbeet and 0.1-0.2 t/ha for potatoes. The recovery of fertilizer N by the potato tubers was 2% higher with the current method than with the other methods. Based on these findings it is concluded that the current recommendation method is preferable to the other methods. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Effect of Dimethyl Sulphoxide on the Expression of Nitrogen Fixation in Bacteria

1977 ◽  
Vol 30 (2) ◽  
pp. 141 ◽  
Author(s):  
Mary L Skotnicki ◽  
Barry G Rolfe
Keyword(s):  
Escherichia Coli ◽  
Nitrogen Fixation ◽  
Energy Metabolism ◽  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Dimethyl Sulphoxide ◽  
Rhizobium Trifolii ◽  
Nif Genes ◽  
E Coli ◽  
Selection Of

Storage in dimethyl sulphoxide (DMSO) of Escherichia coli K12 hybrids carrying nif+ genes from Klebsiella pneumoniae can result in selection of a defective nitrogen-fixing phenotype. Similar results are obtained with E. coli K12 hybrids containing the nitrogep-fixing capacity from Rhizobium trifolii. DMSO appears to affect particular inner membrane proteins associated with energy metabolism in E. coli K12 and four chromosomal regions (chID, chlG, his and unc) are associated with resistance to DMSO.

Phosphorus seed coatings for pasture species. II. Comparison of effectiveness of phosphorus applied as seed coatings, drilled or broadcast, in promoting early growth of phalaris (Phalaris aquatica L.) and lucerne (Medicago sativa L.)

1988 ◽  
Vol 39 (3) ◽  
pp. 447 ◽  
Author(s):  
JM Scott ◽  
GJ Blair
Keyword(s):  
Medicago Sativa ◽  
Plant Height ◽  
Early Growth ◽  
The Other ◽  
Fertilizer Treatment ◽  
Seed Coating ◽  
Phalaris Aquatica ◽  
Medicago Sativa L ◽  
Application Methods ◽  
P Sources

The relative efficiency of phosphorus (P) seed coatings and drilled and broadcast applications of P was investigated in a glasshouse experiment conducted with phalaris (Phalaris aquatica L.) and lucerne (Medicago sativa L.) in P-deficient soil. Two P sources (monocalcium phosphate [MCP] and dicalcium phosphate [DCP]) were used at three rates in seed coatings (0, 5 and 10 kg P ha-1) or at six rates each of drilled or broadcast applications (0, 2.5, 5, 10, 20 and 40 kg P ha-1). MCP coatings severely reduced lucerne emergence and hence yield, but had little effect on phalaris emergence. No other fertilizer treatment affected emergence. The height of phalaris plants at 27 days after sowing (d.a.s.) was increased as much by seed coatings containing MCP at 5 kg P ha-1 as by drill or broadcast applications of MCP at 20 kg P ha-1. Plant height of the MCP seed coating treatments was also less variable than the other application methods, suggesting that the coatings provided more uniform access to P. Seed coatings containing DCP at 10 kg P ha-1 increased phalaris plant height more than did drilled or broadcast applications at 40 kg P ha-1, but there was no effect of any DCP treatment on lucerne growth at 27 d.a.s. The relatively large differences observed in plant height between different application methods at 27 d.a.s. diminished over time until, at 57 d.a.s., only small differences were evident. The dry matter yield and P content of both species were increased by increasing rates of MCP, but DCP had little effect at any rate. The reduced differences between the seed coating treatments and the other application methods at harvest may have been due to the limited soil volume of the pots used; further work is necessary in larger soil volumes to determine the significance of the early growth advantage conferred on phalaris by the phosphorus seed coatings, and to find ways of protecting lucerne from soluble P sources during germination.

Nucleation during primary succession in the Canadian Rockies

1993 ◽  
Vol 71 (8) ◽  
pp. 1093-1096 ◽  
Author(s):  
D. J. Blundon ◽  
D. A. MacIsaac ◽  
M. R. T. Dale
Keyword(s):  
British Columbia ◽  
Nitrogen Fixation ◽  
Key Words ◽  
Rocky Mountains ◽  
Primary Succession ◽  
The Other ◽  
Pioneer Species ◽  
Canadian Rocky Mountains ◽  
Successional Species ◽  
Key Words Colonization

A study of nucleation during primary succession was carried out on age sequences of communities at two sites in the Canadian Rocky Mountains: one at the Mount Robson moraines, British Columbia, the other at Southeast Lyell Glacier, Alberta. The study concentrated on the associations of species with the nitrogen-fixing plants Hedysarum boreale var. mackenzii at Mount Robson moraines and Dryas drummondii at Southeast Lyell Glacier because those plants might serve as nuclei for colonization by other species, thus facilitating succession. The data show that recruitment of later successional species is greater in patches of the two pioneer species, but the fact that recruitment takes place away from the plants also suggests that although there is nucleation, it is not necessary for succession at these sites. Key words: colonization, nitrogen fixation, nucleation, succession.

Rhizosphere relationships of subterranean clover. I. Interactions between strains of Rhizobium trifolii.

1954 ◽  
Vol 5 (2) ◽  
pp. 247 ◽  
Author(s):  
JR Harris
Keyword(s):  
Nitrogen Fixation ◽  
Host Plant ◽  
Root Zone ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Rhizobium Trifolii ◽  
Rhizobial Strain ◽  
Susceptible Host ◽  
Active Elements ◽  
Indigenous Microflora

A study was made of a number of effective and ineffective strains of Rhizobium trifolii in association with subterranean clover (Trifolium subterraneum L.), variety Bacchus Marsh. Where these were inoculated singly into sterilized soils in pot experiments conducted in the greenhouse, typical effective, ineffective, or intermediate plant reactions were obtained. Where more than one strain was inoculated, competition between strains took place and was reflected in nodule pattern and plant reaction. Some strains consistently failed to produce appreciable nodules in the presence of other rhizobia, some showed modification to varying degrees, and some were unaffected. Such behaviour was found to be closely linked with the ability of the strain to proliferate in the rhizosphere of the host plant, and placement of inoculum was shown to influence plant reaction. The concept of "incursion" as a property of a rhizobial strain is suggested. An incursive strain is one able to migrate from the initial site of inoculation and establish an adequate population in the root zone of the susceptible host despite the presence of active elements of the indigenous microflora and microfauna, including antagonistic and predatory forms. The property of incursion is independent of considerations of efficiency of nitrogen fixation or virulence for the host plant. Strains of rhizobia which are poorly incursive may fail to infect the host upon which they have been inoculated if subject to competition from indigenous rhizobia already established in the soil. The necessity of assessing properties of virulence and incursion as well as efficiency of nitrogen fixation in selecting rhizobia for purposes of commercial inoculation is stressed, and the methods of making such tests are discussed.

Chemical nitrogen fixation by using molybdenum and tungsten complexes

2001 ◽  
Vol 73 (2) ◽  
pp. 261-263 ◽  
Author(s):  
Masanobu Hidai ◽  
Yasushi Mizobe
Keyword(s):  
Nitrogen Fixation ◽  
The Other ◽  
Nucleophilic Attack ◽  
Dinuclear Complexes ◽  
Tungsten Complexes ◽  
Other Hand ◽  
Dinitrogen Complexes ◽  
Dinitrogen Complex ◽  
Moderate Yield ◽  
And Tungsten

Dinitrogen complex cis-[W (N2) 2 (PMe2Ph) 4] reacts with an excess of acidic dihydrogen complexes such as trans-[RuCl (h2-H2) (dppe) 2]BF4 (dppe = 1,2-bis (diphenylphosphino) ethane) at 55 °C under 1 atm of H2 to form ammonia in moderate yield. The reaction is presumed to proceed through nucleophilic attack of the remote nitrogen of the coordinated dinitrogen on the dihydrogen ligand. The coordinated dinitrogen is also protonated by treatment with hydrosulfido-bridged dinuclear complexes such as [Cp*Ir (m-SH) 3IrCp*]Cl (Cp* = h5-C5Me5) to afford ammonia. On the other hand, the synthetic cycle for the formation of pyrrole and N-aminopyrrole from dinitrogen and 2,5-dimethoxytetrahydrofuran has been established starting from dinitrogen complexes of the type trans-[M (N2) 2 (dppe) 2 ] (M = Mo, W).

scholarly journals Competition between related strains of nodule bacteria and its influence on infection of the legume host

1941 ◽  
Vol 130 (858) ◽  
pp. 32-59 ◽  
Keyword(s):  
Growth Rate ◽  
Nitrogen Fixation ◽  
Root System ◽  
Short Duration ◽  
Pure Culture ◽  
The Other ◽  
Initial Growth ◽  
Nodule Bacteria ◽  
Long Period ◽  
Different Strains

The work deals with the behaviour of mixed strains of nodule bacteria towards each other and towards their legume host. It introduces the concept of dominance in competition between strains. This dominance is independent of degree of effectiveness as regards nitrogen fixation. Where tow strains of nodule bacteria are both present in the surroundings of their host's root system, active competition between them may cause the strain having the higher initial growth rate almost completely to check multiplication of the other strain outside the plant. This dominant strain will then be responsible for nearly all the nodules. In peas and soy beans, where growth of the root sysytem is rapid and of comparatively short duration, the nodule-producing capacity of the plant may be partially or wholly satisfied by the nodules produced within the first few weeks, so that further infection, whether by the same or by a different strain, is checked or inhibited. In clover, whose root system continues to grow over a long period, the first-formed nodules do not stop further nodules from being formed either by the same or by a different strain. There are large differences in the rates of appearance and final numbers of nodules produced by different strains supplied in pure culture, particularly with clover. The relative numbers of nodules produced by the two strains simultaneously applied to the roots is conditioned by the specific infectivity peculiar to each strain, unless some other factor, such as competition outside the plant, masks this effect.

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