Misconceptions and practical problems in the use of 15N soil enrichment techniques for estimating N2 fixation

1993 ◽  
Vol 152 (1) ◽  
pp. 25-52 ◽  
Author(s):  
S. K. A. Danso ◽  
G. Hardarson ◽  
F. Zapata
Keyword(s):  
N2 Fixation ◽  
Soil Enrichment ◽  
Enrichment Techniques

An assessment of soil enrichment by actinorhizal N2 fixation using δ 15N values in a chronosequence of deglaciation at Glacier Bay, Alaska

2003 ◽  
pp. 11-17
Author(s):  
Steven J. Kohls ◽  
Dwight D. Baker ◽  
Chris van Kessel ◽  
Jeffrey O. Dawson
Keyword(s):  
N2 Fixation ◽  
Glacier Bay ◽  
Soil Enrichment ◽  
Δ 15N

Effects of below-ground nitrogen on N balances of field-grown fababean, chickpea, and barley

2003 ◽  
Vol 54 (4) ◽  
pp. 333 ◽  
Author(s):  
Dil F. Khan ◽  
Mark B. Peoples ◽  
Graeme D. Schwenke ◽  
Warwick L. Felton ◽  
Deli Chen ◽  
...  
Keyword(s):  
N2 Fixation ◽  
Cropping Systems ◽  
Natural Abundance ◽  
Yield Data ◽  
Soil Enrichment ◽  
15N Enrichment ◽  
South Wales ◽  
Peak Biomass ◽  
Below Ground ◽  
15N Urea

The objectives of this study were to quantify below-ground nitrogen (BGN) of rainfed fababean (Vicia faba), chickpea (Cicer arietinum), and barley (Hordeum vulgare) and to use the values to determine N balances for the 3 crops. The BGN fraction of legumes in particular represents a potentially important pool of N that has often been grossly underestimated or ignored in calculating such balances. A field experiment was conducted at Breeza on the Liverpool Plains, New South Wales, in which BGN of fababean, chickpea, and barley was estimated using 15N methodologies. Plants were grown in 0.32-m2 microplots and labelled with 15N on 5 occasions during vegetative growth with a total of 1.0 mL of 0.5% 15N urea (98 atom% 15N) using leaf-flap (fababean), leaf-tip (barley), or cut petiole (chickpea) shoot-labelling procedures. At peak biomass (146–170 days after sowing), all plant material and soil to 45 cm depth was sampled from one microplot in each replicate plot and analysed for dry matter (DM), %N, and 15N. At plant maturity, the remaining 3 microplots in each replicate plot were harvested for shoot and grain DM and N. With fababean, 15N enrichments of intact roots and shoots were reasonably uniform at 537‰ and 674‰, respectively. Microplot soil at 0–25 cm depth had a 15N enrichment of 18‰ (natural abundance of 6.1‰). The 25–45 cm soil enrichment was 8.7‰ (natural abundance of 6.3‰). In contrast, 15N enrichment of chickpea shoots was about twice that of recovered roots (685‰ v. 331‰), and the soil enrichment was relatively high (30‰ and 8.8‰ for the 0–25 and 25–45 cm depths, respectively). The 15N enrichments of barley shoots and recovered roots were 2272‰ and 1632‰, respectively, with soil enrichments of 34‰ and 10.7‰ for the 0–25 and 25–45 cm depths, respectively. Estimates of BGN as a percentage of total plant N, after adjusting the 15N shoot-labelling values of fababean and chickpea for uneven distribution of 15N-depleted nodules, were 24% for fababean, 68% for chickpea, and 36% for barley. The BGN values were combined with N2 fixation (fababean and chickpea only) and shoot and grain yield data (all 3 species) to construct N budgets. The inclusion of BGN in the budgets increased N balances by 38 kg N/ha to +36 kg N/ha for fababean and by 93 kg N/ha to +94 kg N/ha for chickpea. As there was no external (N2 fixation) input of N to barley, the inclusion of BGN made no difference to the N balance of the crop of –74 kg N/ha. Such values confirm the importance of BGN of N2-fixing legumes in the N economies of cropping systems.

Selection of soybean (Glycine max) lines for increased tolerance of N2 fixation to drying soil

Agronomie ◽  
2001 ◽  
Vol 21 (6-7) ◽  
pp. 653-657 ◽  
Author(s):  
Thomas R. Sinclair ◽  
Larry C. Purcell ◽  
Vincent Vadez ◽  
Rachid Serraj
Keyword(s):  
Glycine Max ◽  
N2 Fixation ◽  
Selection Of

Vegetation on technogenic habitats in the far-north taiga and south forest-tundra of the European North-East of Russia. Alliance Chamerio angustifolii–Matricarion hookeri A. Ishbirdin et al. 1996

2019 ◽  
pp. 77-94
Author(s):  
I. A. Likhanova ◽  
G. S. Shushpannikova ◽  
L. P. Turubanova
Keyword(s):  
Komi Republic ◽  
Oil Fields ◽  
Soil Enrichment ◽  
Far North ◽  
North East ◽  
European North ◽  
Ecological Scales ◽  
Floristic Classification ◽  
Made In

The results of floristic classification of technogenic vegetation (alliance Chamerio angustifolii–Matricarion hookeri A. Ishbirdin et al. 1996, order Chamerio–Betuletalia nanae Khusainov et al. in Sumina 2012, class Matricario–Poetea arcticae A. Ishbirdin in Sumina 2012) conducted by the Braun-Blanquet method (Braun-Blanquet, 1964; Mirkin, Naumova, 1998) are given. 98 geobotanical relevés, made in 1981–2013 on areas of oil fields and suburbs of the Usinsk city (Komi Republic) (56–60о N, 67–66о E), were involved into analysis (Fig. 1). The ecological parameters like moisture (F) and mineral nitrogen soil enrichment (N) were assessed using the Ellenberg ecological scales (Ellenberg, 1974).

Identification of Promiscuous Nodulating Soybean Efficient in N2 Fixation 1

Crop Science ◽  
1985 ◽  
Vol 25 (4) ◽  
pp. 660-663 ◽  
Author(s):  
E. L. Pulver ◽  
E. A. Kueneman ◽  
V. Ranga‐Rao
Keyword(s):  
N2 Fixation

scholarly journals The Quorum Sensing Auto-Inducer 2 (AI-2) Stimulates Nitrogen Fixation and Favors Ethanol Production over Biomass Accumulation in Zymomonas mobilis

2021 ◽  
Vol 22 (11) ◽  
pp. 5628
Author(s):  
Valquíria Campos Alencar ◽  
Juliana de Fátima dos Santos Silva ◽  
Renata Ozelami Vilas Boas ◽  
Vinícius Manganaro Farnézio ◽  
Yara N. L. F. de Maria ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Quorum Sensing ◽  
Ethanol Production ◽  
N2 Fixation ◽  
Energy Demand ◽  
Zymomonas Mobilis ◽  
Biomass Accumulation ◽  
High Energy ◽  
Gram Negative ◽  
Expression Of Genes

Autoinducer 2 (or AI-2) is one of the molecules used by bacteria to trigger the Quorum Sensing (QS) response, which activates expression of genes involved in a series of alternative mechanisms, when cells reach high population densities (including bioluminescence, motility, biofilm formation, stress resistance, and production of public goods, or pathogenicity factors, among others). Contrary to most autoinducers, AI-2 can induce QS responses in both Gram-negative and Gram-positive bacteria, and has been suggested to constitute a trans-specific system of bacterial communication, capable of affecting even bacteria that cannot produce this autoinducer. In this work, we demonstrate that the ethanologenic Gram-negative bacterium Zymomonas mobilis (a non-AI-2 producer) responds to exogenous AI-2 by modulating expression of genes involved in mechanisms typically associated with QS in other bacteria, such as motility, DNA repair, and nitrogen fixation. Interestingly, the metabolism of AI-2-induced Z. mobilis cells seems to favor ethanol production over biomass accumulation, probably as an adaptation to the high-energy demand of N2 fixation. This opens the possibility of employing AI-2 during the industrial production of second-generation ethanol, as a way to boost N2 fixation by these bacteria, which could reduce costs associated with the use of nitrogen-based fertilizers, without compromising ethanol production in industrial plants.

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