scholarly journals Reassessment of the Contribution of Belowground N from Soybean after Testing Different 15N Leaf-Labelling Strategies

2021 ◽  
Author(s):  
Robert Michael Boddey ◽  
Karla E.C. Araujo ◽  
Carlos Vergara ◽  
Ricardo Cesario dos Santos ◽  
Wadson Santos ◽  
...  
Keyword(s):  
Vegetative Stage ◽  
N Accumulation ◽  
Labelling Technique ◽  
Residual N ◽  
Grain Crop ◽  
Total Plant ◽  
Soybean Plants ◽  
Final Harvest

Abstract Purpose: Soybean is the most important grain crop in Brazil with a mean N accumulation of over 250 kg N ha-1, principally from biological N2 fixation. The residual N benefit depends heavily on the quantity of the belowground N at harvest, much which cannot be directly recovered in roots. The purpose of this study was to investigate different aspects of the 15N leaf-labelling technique to quantify non-recoverable root N (NRRN) derived from senescent roots and nodules (rhizodeposits). Methods: Soybean plants were grown in pots of soil and at 27 days after planting (vegetative stage V4) cut or whole leaves were exposed to highly enriched 15N-labelled urea or glutamine. Seven sequential harvests of the plants and soil were taken until the final grain harvest at 70 days after labelling.Results: After only 48 h, the plants labelled with 15N urea transferred approximately 5% to the soil, while only 1% was found in the roots. Leakage of 15N label was even more pronounced when the leaves were labelled with 15N glutamine. After this initial leakage, the excess 15N deposited in the soil only increased by a further 2.6% of applied label, which suggested that only part of this N represented senescence of roots or nodules.Conclusions At the final harvest, N in roots separated from the soil amounted to 6.4% of total plant N. Discounting the early rapid deposition of 15N-enriched N to the soil, our calculations indicated that at final harvest the total NRRN was 2.8% of total plant N.

Biology of Acacia pulchella R.br. With Special Reference to Symbiotic Nitrogen Fixation

1981 ◽  
Vol 29 (5) ◽  
pp. 579 ◽  
Author(s):  
D Monk ◽  
JS Pate ◽  
WA Loneragan
Keyword(s):  
Plant Density ◽  
Natural Populations ◽  
Growth Period ◽  
Sand Culture ◽  
Nitrogen And Phosphorus ◽  
N Accumulation ◽  
Growing Seasons ◽  
Reduction Activity ◽  
C2h2 Reduction ◽  
Total Plant

Growth, reproduction and longevity of the fire weed Acacia pulchella var. glaberrima were examined in natural populations of known age in coastal sands in and around Perth, W.A. Dense populations (10000 plantsiha) were established after a summer burn; plant density was 30% of its initial value at 4 years. less than 8% at 13 years. Plants accumulated dry matter, nitrogen and phosphorus throughout a 13-year growth period. Seed production commenced at 2 years, reached a maximum (12000 seeds per plant per year) at 3 or 4 years declining to 2000 seedsiplant in the 13th year. Only a small fraction of the shed seed accumulated in soil under the stands. Changes in total plant N, nodule weightlplant, and C2H2 reduction capacity of detached nodules were followed in populations in their first, second and fourth growing seasons. A new set of nodules formed with the autumn rains, peak nodule mass and C2H2 reduction activity were recorded in July-October, and virtually no nodules survived the summer into a second growing season. A glasshouse study of N accumulation and C2H2 reduction by nodules in minus N sand culture gave acalibration value of 2.26 mol C2H2 : mol N2 fixed. Applying this value to data from nativepopulations, 8% of the N accumulated by first season plants, 45% of the N of second season plants and 68% of the N of fourth season plants were estimated to be derived from symbiosis. Average annual returns of N to the ecosystem were estimated at 3.9 kg/ha, probably more than half of this from N2 fixation. Progressive death of plants in the populations gave the greatest return ( 1.9 kg N per ha per yr), the remainder from litter (1 kg N per ha per yr) and shed seed ( 1 kg N per ha per yr).

scholarly journals Soybeans Competitiveness with Morning Glory

2016 ◽  
Vol 34 (1) ◽  
pp. 25-33
Author(s):  
F. PICCININI ◽  
T.N. MARTIN ◽  
S.L.O. MACHADO ◽  
N.D. KRUSE ◽  
R. SCHMATZ
Keyword(s):  
Leaf Area ◽  
Dry Mass ◽  
Morning Glory ◽  
Replacement Series ◽  
Yield And Quality ◽  
Randomized Design ◽  
Total Plant ◽  
Soybean Plants ◽  
Herbicide Use

Weeds interfere negatively on development, yield and quality of soybeans (Glycine max). Inadequate weed control by herbicide use can select for resistant or tolerant biotypes, leading to a shift in the weed flora. An example is the increase of incidence of morning glory (Ipomoea spp.) in soybeans growing areas in South Brazil. The aim of this study was to determine the competitiveness of soybeans intercropped with I. triloba, I. indivisa and I. purpurea through a replacement experiments series. Greenhouse experiments were conducted in a completely randomized design with four replications. The first experiment was carried out aiming to get the plant population while total plant dry mass remained constant. Other experiments were done under replacement series experiments with soybeans and morning glory ratios of 100:0, 75:25, 50:50, 25:75 and 100:0 using the 250 plant m-2 defined by the preliminary experiment. Leaf area, root and shoots dry mass were assessed. Diagrams along with index interpretation were used to performed a competitiveness analysis. Soybeans showed greater competitiveness as I. triloba, I. purpurea and I. indivisa species for the leaf area, root and shoots dry mass variables. Intraspecific competition prevails between soybean plants whilst interspecific competition prevails for morning glory.

Effect of soybean population density on soybean yield, nitrogen accumulation and residual nitrogen

1988 ◽  
Vol 28 (1) ◽  
pp. 99 ◽  
Author(s):  
MJ Blumenthal ◽  
VP Quach ◽  
PGE Searle
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Dry Matter ◽  
Nitrogen Accumulation ◽  
Soil N ◽  
Population Densities ◽  
N Accumulation ◽  
Soybean Yield ◽  
Residual Nitrogen ◽  
Residual N

The effect of soybean population density on soybean yield, nitrogen accumulation and residual nitrogen was examined at Camden, N.S.W. (34�S.). In the first experiment, treatments were soybeans (cv. Ransom) at 50, 100, 200 and 400 x 103 plants ha-1; maize (cv. XL66); and a weed-free fallow. Total dry matter yields of tops and grain yields were highest at 200x 103 plants ha-1 (6214 and 3720 kg ha-1, respectively). The yield component most affected by population density was number of branches per plant, with values decreasing with increasing population density. The proportion of unfilled pods was highest at the highest population density. Total nitrogen (N) accumulation in the tops and in the grain was also at a maximum at 200x 103 plants ha-1. The rate of dry matter accumulation declined during pod filling at all population densities. N accumulation continued at high rates throughout the growing season except in the 400x 103 plants ha-1 population. There was a trend for residual dry matter and N in residues to increase with increasing population density. After grain and forage harvest of the first experiment, a crop of wheat (cv. Kite) was sown over the whole area to determine residual N available at anthesis and at maturity (experiment 2). The values of N accumulation in the wheat at maturity were 24 kg N ha-l for the maize treatment, 40-60 kg N ha-l for the soybean treatments and 69 kg N ha-1 for the fallow treatment. Grain yield and grain N followed the pattern of dry matter production and N accumulation at final harvest. The data suggest that soybean depletes soil N to a lesser extent than does maize. For the soybean treatments, there was a trend of increasing residual N at the 3 highest population densities (40-60 kg N ha-1). This was probably a result of an increase in N in leaf fall and in decaying tops and roots at the highest population density. The high value (57 kg N ha-l) at the lowest population density may be due to soybean plants at this density not using as much soil N as the other soybean treatments. No benefit in residual N was gained from planting soybeans at a density beyond the optimum for grain yield when residues were removed by forage harvesting.

scholarly journals Effects of nitrogen accumulation and partitioning of dry matter and nitrogen of vegetables. 1. Brussels sprouts

1995 ◽  
Vol 43 (4) ◽  
pp. 419-433
Author(s):  
H. Biemond ◽  
J. Vos ◽  
P.C. Struik
Keyword(s):  
Dry Matter ◽  
Leaf Number ◽  
Nitrogen Accumulation ◽  
N Accumulation ◽  
Total N ◽  
Brussels Sprouts ◽  
Apical Buds ◽  
Nitrate N ◽  
N Concentration ◽  
Final Harvest

Three greenhouse trials and one field trial were carried out on Brussels sprout cv. Icarus SG2004 in which the treatments consisted of different N amounts and application dates. DM and N accumulation in stems, apical buds and groups of leaf blades, petioles and sprouts were measured frequently throughout crop growth. Total amounts of accumulated DM and N were affected by amount of N applied and date of application, but the final harvest indexes for DM and N (0.10-0.35 and 0.20-0.55, respectively) were not significantly affected by treatments in most experiments. Nitrate N concentrations were only high (up to about 2%) shortly after planting. The total N concentration of leaf blades and petioles increased with increasing leaf number. This increase resulted from a decreasing N concentration during the leaf's life. The total N concentration in sprouts changed little with leaf number.

Nitrogen fixation in field beans (Vicia faba) as affected by population density, shading and its relationship with soil moisture

1977 ◽  
Vol 88 (2) ◽  
pp. 303-310 ◽  
Author(s):  
Janet I. Sprent ◽  
Alison M. Bradford
Keyword(s):  
Acetylene Reduction ◽  
Field Experiments ◽  
Reduction Technique ◽  
N Fixation ◽  
N Accumulation ◽  
Total N ◽  
Nodule Senescence ◽  
Total Plant ◽  
Acetylene Reducing Activity ◽  
High Yields

SUMMARYN fixation data, estimated by the acetylene reduction technique and by total N content are given for the field experiments reported by Sprent, Bradford & Norton (1977).Maximum potential acetylene reducing activity per plant varied little from year to year. At low population densities a maximum rate of activity was observed shortly after flowering. As density increased this maximum became less pronounced and environmental factors (such as water supply) exerted increasing effects on activity. Shading prolonged activity and delayed nodule senescence.Total plant N continued to increase almost to seed maturation. As plants aged, the acetylene reduction technique progressively underestimated N accumulation. Maximum Nfixed/ha/year was over 600 kg. Itis concluded that the potential for N fixation in this crop is sufficient to sustain high yields.

Temporal dynamics of nitrogen rhizodeposition in field pea as determined by 15N labeling

2013 ◽  
Vol 93 (5) ◽  
pp. 941-950 ◽  
Author(s):  
Melissa M. Arcand ◽  
J. Diane Knight ◽  
Richard E. Farrell
Keyword(s):  
Temporal Dynamics ◽  
Field Pea ◽  
N Balance ◽  
Vegetative Stage ◽  
Root Turnover ◽  
Seed Harvest ◽  
15N Labeling ◽  
Below Ground ◽  
Total Plant ◽  
Intact Roots

Arcand, M. M., Knight, J. D. and Farrell, R. E. 2013. Temporal dynamics of nitrogen rhizodeposition in field pea as determined by 15 N labeling. Can. J. Plant Sci. 93: 941–950. Assessing the contribution of symbiotically fixed N2 to soil from pulse crops necessitates a full accounting of the total crop residue N remaining in the field after seed harvest. Below-ground N, including root and rhizodeposit N, comprises an important component of this total plant N balance – without it the N input to soil is underestimated. Under controlled conditions in a greenhouse, N in intact roots and N rhizodeposition were quantified in field pea (Pisum sativum L.) using the cotton-wick 15N labeling technique. Plants were supplied with 15N on a continuous basis and harvested at the vegetative stage (nine leaves unfolded), flowering, and maturity. As the plants aged, the 15N enrichment in the rhizosphere soil decreased, whereas that in the bulk soil increased, suggesting that N released as root exudates comprised a more important proportion of N rhizodeposition in plants at the early vegetative stage compared with mature plants. In mature plants, N rhizodeposition was comprised predominantly of N associated with root turnover. The contribution of N rhizodeposition recovered in soil to the total plant N balance decreased from 17.8% at the vegetative stage harvest, to 12.3% at flowering, and finally to 7.5% at maturity. However, the total amount of root-derived N released to soil by pea increased with plant development. Below-ground N, including N rhizodeposition and N in intact roots contributed 11.3% to the total plant N balance of mature pea.

Ovipositional Sites of the Potato Leafhopper (Homoptera: Cicadellidae) on Vegetative Stage Soybean Plants

1985 ◽  
Vol 14 (2) ◽  
pp. 165-169 ◽  
Author(s):  
A. M. Simmons ◽  
L. D. Godfrey ◽  
K. V. Yeargan
Keyword(s):  
Potato Leafhopper ◽  
Vegetative Stage ◽  
Soybean Plants

Effects of Azospirillum inoculation on root infection and nitrogen incorporation in wheat

1983 ◽  
Vol 29 (8) ◽  
pp. 924-929 ◽  
Author(s):  
Vera L. D. Baldani ◽  
José Ivo Baldani ◽  
Johanna Döbereiner
Keyword(s):  
Dry Matter ◽  
Field Experiments ◽  
Nitrogen Accumulation ◽  
Root Infection ◽  
Wheat Roots ◽  
N Accumulation ◽  
Total N ◽  
Total Plant ◽  
Chloramine T ◽  
Heading Stage

In two field experiments, wheat was inoculated with various strains of Azospirillum spp. The two A. brasilense nir− strains isolated from surface-sterilized wheat roots increased the number of Azospirillum in surface-sterilized roots, plant dry matter, and percent N. The total N accumulated in plant tops at heading stage was increased by 30% in the first experiment (strain Sp 107 st) and by 51 and 89% (strains Sp 107 st and Sp 245, respectively) in the second experiment. The Azospirillum numbers (MPN) in chloramine-t treated roots were correlated with total nitrogen accumulation in plant tops (r = 0.92**). Numbers of Azospirillum in nonsterilized roots did not correlate with total plant N accumulation.

scholarly journals Soil Flooding Tolerance in Lentil at Vegetative Stage

2013 ◽  
Vol 18 (2) ◽  
pp. 17-24 ◽  
Author(s):  
B Nessa ◽  
MR Islam ◽  
MM Haque ◽  
JU Ahmed
Keyword(s):  
Plant Biomass ◽  
Recovery Period ◽  
Vegetative Stage ◽  
Flooding Tolerance ◽  
Relative Growth ◽  
Soil Flooding ◽  
Excess Water ◽  
Total Plant Biomass ◽  
Total Plant ◽  
Plant Components

The experiment compared the relative tolerance of some advanced lines and a variety of lentil viz. BD3859, BD3905, BD3867, ILL5087, ILL5133 and BINAmasur1 (variety) to soil flooding. The growth rates of the genotypes considerably reduced when flooding imposed at vegetative stage. However, the genotypes responded differently to flooding onward during recovery period. Leaf and roots showed highly vulnerable to flooding. Flooding promoted extensive leaf senescence and desiccation. Flooding induced damaging of root system was highly striking, despite there existed remarkable recoveries in some genotypes. The adverse effect of flooding was less pronounced on stem than other plant components. However, shoot growth reduction was 76-86% relative to control. Relative growth rate (RGR) of most plant components showed negative rate during flooding, but it varied from negative to positive during recovery period. Considering total plant biomass, flooding tolerance (FT) indices indicated that BINAmasur1 and BD3859 had comparatively better degree of tolerance to excess water. In contrast, ILL5133 and ILL5087 were susceptible to flooding for having negative FT indices.DOI: http://dx.doi.org/10.3329/pa.v18i2.17460 Progress. Agric. 18(2): 17 - 24, 2007

N2 fixation and dry matter and N accumulation in soybean lines with different seed-fill periods

1992 ◽  
Vol 72 (4) ◽  
pp. 1067-1074 ◽  
Author(s):  
B. L. Vasilas ◽  
R. L. Nelson
Keyword(s):  
Glycine Max ◽  
Seed Yield ◽  
Dry Matter ◽  
Dry Matter Accumulation ◽  
N Accumulation ◽  
Total N ◽  
Glycine Max L ◽  
Small Plot ◽  
Total Plant ◽  
Seed Fill

A positive relationship generally exists between the duration of seed-fill period (SFP) and seed yield in soybean, but exceptions have been reported. The objective of this research was to determine if differences in N2 fixation or N accumulation could explain inconsistent relationships between duration of SFP and seed yield in soybean. For this study, five experimental soybean (Glycine max L. [Men.]) lines were selected on the bases of differences in SFP and seed yield in previous experiments. The experiment was designed to compare lines differing in both SFP and seed yield, differing in SFP but not seed yield, and differing in seed yield but not SFP. Total N2 fixation, using 15N-dilution techniques; total N accumulation, using a semi-micro-Kjeldahl procedure; and total dry matter accumulation, including all vegetative material abscised before maturity were measured on these lines grown in a Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudolls) in 1984 and 1985 at Urbana, IL. Mean dinitrogen fixed ranged from 36 to 76 kg ha−1 in 1984 and from 65 to 113 kg ha−1 in 1985. The percentage of the total plant N derived from fixation ranged from 17 to 35% in 1984 and from 32 to 48% in 1985. Statistically significant differences in seed yield were not detected in this experiment because of the high coefficient of variation associated with the small plot size. High N2 fixation was not related to duration of SFP or previous seed yield classification. Total plant N did not differ among these genotypes. For these soybean lines differences in duration of SFP and previous seed yield classification were not related to total N2 fixation or N accumulation.Key words: Glycine max, harvest index, N partitioning, N2 fixation, seed-fill period

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