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.

scholarly journals Nitrogen fixation by caucasian clover and white clover in irrigated ryegrass pastures

2001 ◽  
pp. 171-175
Author(s):  
K.H. Widdup ◽  
R.G. Purves ◽  
A.D. Black ◽  
P. Jarvis ◽  
R.J. Lucas
Keyword(s):  
Nitrogen Fixation ◽  
White Clover ◽  
N2 Fixation ◽  
N Uptake ◽  
Pastoral System ◽  
Pasture Production ◽  
Trifolium Ambiguum ◽  
Enrichment Technique ◽  
15N Enrichment ◽  
Clover Content

The N2 fixation ability of caucasian clover was compared with that of white clover in irrigated ryegrass pastures over years 2 and 3 of a grazing experiment, using the 15N enrichment technique. 'Endura' caucasian clover was inoculated with the specific Rhizobium strain ICC148. The N concentration in clover herbage and the proportion of clover N derived from N2 fixation (PN) were similar for both clovers at averages of 4.6%N and 50-60% respectively over the 2 years. The amount of N2 fixed per hectare was directly related to the amount of clover dry matter (DM) produced by the two clover species. Caucasian clover produced four times the DM yield of white clover in year 2 (5400 cf. 1450 kg DM/ha) and four times the amount of N2 fixed in herbage (136 cf. 36 kg N/ ha). In year 3, caucasian clover produced 50% more clover DM (3450 cf. 2370 kg DM/ha) and N2 fixed (98 cf. 66 kg N/ha) than white clover. The increased N input from caucasian clover increased grass %N and N uptake from soil in caucasian clover pastures resulting in higher total pasture production compared with white clover pastures (15.7 cf. 14.2 t DM/ha) by year 3. In this study, caucasian clover demonstrated greater potential than white clover to meet the N demands of high-yielding perennial ryegrass in an intensive pastoral system. Keywords: clover content, Lolium perenne, nitrogen fixation, pasture production, Trifolium ambiguum, T. repens

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.

Factors associated with biological nitrogen fixation in dairy pastures in south-western Victoria

1999 ◽  
Vol 50 (2) ◽  
pp. 261 ◽  
Author(s):  
Penny A. Riffkin ◽  
Paul E. Quigley ◽  
Gavin A. Kearney ◽  
Fiona J. Cameron ◽  
Robert R. Gault ◽  
...  
Keyword(s):  
White Clover ◽  
Soil Texture ◽  
Dry Matter ◽  
Chemical Properties ◽  
Soil Chemical Properties ◽  
Available Phosphorus ◽  
N Fixation ◽  
Nematode Density ◽  
Factors Associated ◽  
Western Victoria

A survey of 71 sites was conducted in the dairying districts of south-western Victoria in October 1994 to determine factors associated with nitrogen (N) fixation in white clover based pastures. Twenty-eight factors (environmental, microbiological, management, soil, and pasture) were considered in relation to 2 indicators of N fixation by white clover, %Ndfa (percentage of total plant N derived from the atmosphere, as determined by the 15N natural abundance method) and kg of N fixed per tonne herbage dry matter (legume and non-legume). On light-textured soils (sandy loams), soil potassium, rhizobia numbers, total soil N, and density of the nematode Pratylenchus sp. accounted for 72% of variation in %Ndfa. On medium-textured soils (clay loams), crude protein of perennial ryegrass and plant-available phosphorus in the soil accounted for 30% of variation in %Ndfa. The amount of N fixed was influenced by different factors, again depending on soil texture. Soil chemical properties accounted for 31% variation on the medium-textured soils with nematode density, pasture quality, and soil chemical properties accounting for 77% of variation on light-textured soils. Amounts of N fixed per tonne herbage dry matter produced averaged 8.2 kg on the light-textured soils and 7.3 kg on the medium-textured soils. Average %Ndfa values were 67% and 60% on light- and medium-textured soils, respectively. Effects of soil texture on N fixation were attributed to the different cation exchange and water-holding capacities of the soils and highlight the importance of considering soil type in N fixation studies.

scholarly journals Yield benefits of pasture mixtures with species drilled in the same and alternate rows

2018 ◽  
pp. 243-248
Author(s):  
Alistair D Black ◽  
S Anderson ◽  
S K Dalgety ◽  
C A Hassall ◽  
T S Myint ◽  
...  
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Dry Matter ◽  
Ternary Mixtures ◽  
Synergistic Interactions ◽  
Constituent Species ◽  
Diversity Effect ◽  
Binary And Ternary Mixtures ◽  
Lincoln University ◽  
Diversity Effects

This study investigated the effect of sowing species in alternate drill rows on dry matter (DM) yield of pasture mixtures. Seven mixtures of ‘Base’ perennial ryegrass, ‘Tonic’ plantain and ‘Apex’ white clover (three pure, three binary and one ternary) were drilled into plots in March 2015 at Lincoln University. Binary and ternary mixtures were also sown with species in alternate drill rows. Ryegrass-white clover and plantain-white clover mixtures yielded more than the average monoculture yields of their constituent species (over-yielding). This diversity effect averaged 7.01 t DM/ha in Year 1 (2015/2016) and 3.45 t DM/ha in Year 2 (2016/2017) of sown yield (total minus weeds) when species were drilled together. Diversity effects were due to synergistic interactions and white clover interacted more strongly with plantain than ryegrass. There was no additional yield benefit from increasing the number of species from two to three in the mixture, and from sowing species in alternate rows.

scholarly journals Annual dry matter, metabolisable energy and nitrogen yields of six dryland pastures six and seven years after establishment

2010 ◽  
pp. 177-184 ◽  
Author(s):  
A. Mills ◽  
D.J. Moot
Keyword(s):  
White Clover ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Pasture Quality ◽  
N Yield ◽  
Nitrogen Yields ◽  
Metabolisable Energy ◽  
Lincoln University

Dry matter (DM) yields, botanical composition, liveweight production and pasture quality of six grazed dryland pastures established in 2002 at Lincoln University, Canterbury, are reported for Years 6 (2007/08) and 7 (2008/09). Lucerne (Medicago sativa) yielded 14.0 t DM/ha/yr and sheep liveweight (LW) production totalled 903 (2007/08) and 1 141 kg/ha/yr (2008/09). Metabolisable energy (ME) on offer (~134 GJ/ha/yr) and N yield (>500 kg/ha/yr) from the lucerne exceeded those of grass-based pastures. Yields (9.8- 11.2 t DM/ha/yr) and liveweight production (814-912 kg/ha/yr) from cocksfoot (Dactylis glomerata) pastures established with subterranean (Trifolium subterraneum) clover were greater than all other grass-based pastures. Annual ME was 79-96 GJ/ha and N yield was 269- 316 kg/ha from the cocksfoot, subterranean clover and volunteer white clover (T. repens) components. For Year 7, the contribution of unsown weeds and grasses in cocksfoot-based pastures was ~28% of total annual yield compared with 55% in ryegrass (Lolium perenne)/ white clover pastures. Consequently, the ME and N yields from sown pasture components in ryegrass/white clover pastures were lower than those from cocksfootbased pastures. These results indicate dryland farms with lucerne and/or cocksfoot/sub clover pastures can produce higher DM yields from more persistent pasture species. Persistence led to more ME and N on offer to grazing livestock, which resulted in higher liveweight production than from the ryegrass pastures. Keywords: balansa clover, Caucasian clover, growth rates, pasture quality, T. ambiguum, T. michelianum

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.

scholarly journals Managing white clover for productive and profitable sheep farming in Southland

2000 ◽  
pp. 137-140
Author(s):  
J.P.J. Eerens ◽  
D.L. Ryan
Keyword(s):  
Nitrogen Fixation ◽  
New Zealand ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Dry Matter ◽  
Research Station ◽  
Pasture Management ◽  
Pasture Production ◽  
Clover Root ◽  
Pastoral Farming

White clover is often listed as one of the factors contributing to profitable pastoral farming in New Zealand. The positive aspects of white clover have been presented in a balanced manner in publications by scientists, environmentalists and farmers able to exploit these positive aspects. Increasingly, pastures contain sub-optimal levels of clover, as a result of pasture management that is detrimental to clover, including the increasing use of fertiliser nitrogen. In some regions of New Zealand, farmers can legitimately point to pests such as the clover root weevil and factors such as the ryegrass endophyte as causing restrictions in clover production, but this is less the case in Southland. Environmental conditions in Southland are well suited for ryegrass-white clover pastures. Wellmanaged ryegrass-white clover pastures containing the best regional cultivars can achieve high financial returns. A number of trials at the Gore Research Station are reviewed; they demonstrated that on mixed ryegrass-white clover swards farmers can produce nearly 25% more dry matter, 40% more carcass weight and 25% more wool than on pastures with ryegrass alone receiving 270 kg N/ha/year. The yield advantage would have been greater still if they were compared with typical Southland pastures. Not only was 180 kg more carcass and 17 kg more wool produced per hectare on mixed swards, but nitrogen fixation by clover produced more than $300 worth of nitrogen per hectare. The yield advantage achievable from the ryegrass-white clover swards requires specific pasture management, particularly in spring- summer and the use of adapted white clover cultivars. Keywords: cultivars, Lolium perenne, nitrogen, pasture production, perennial ryegrass, set stocking, Trifolium repens, white clover, wool

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.

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.

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