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.

Nitrogen Balance of Field Pea Crops in South Western Australia, Studied Using the 15N Natural Abundance Technique

1994 ◽  
Vol 21 (4) ◽  
pp. 533 ◽  
Author(s):  
EL Armstrong ◽  
JS Pate ◽  
MJ Unkovich
Keyword(s):  
Western Australia ◽  
N Uptake ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Field Pea ◽  
N Balance ◽  
Total N ◽  
Peak Biomass ◽  
Biomass N ◽  
Total Plant

The nitrogen economies of six contrasting field pea (Pisum sativum L.) genotypes were examined at three widely separated sites in south Western Australia, using the 15N natural abundance technique to asssess proportional dependence on fixed N, harvests at peak biomass to assess total N yields and harvests at crop maturity to examine partitioning of N between seed and non harvested crop residues. The budgets for one site (Wongan Hills) included N of nodulated roots which on average comprised 12% of total plant N at peak crop biomass and 25% of recoverable plant N after harvest of seed. At this site maximum potential (residual) benefits to a following crop (peak total plant biomass N - N uptake from soil and N taken off as harvested seed) varied between genotypes from 8 to 41 g N ha-1 (mean 26; n = 6). Data for the other two sites, based solely on N budgets of above-ground parts, provided evidence of substantial site- and genotype-specific differences in N balance in terms of shoot residues (i.e. + 7 to - 24 kg N ha-1 (mean - 5) at Avondale, + 40 to - 29 (mean + 3) at Mt Barker). The results collectively indicated a general relationship between peak biomass N of a crop and its potential or otherwise to effect a net input of residue N to the ecosystem. There were, however, considerable variations between genotypes and sites due to differences in proportional dependence on fixation (range across all sites and genotypes 60-91%) and crop harvest indices for N (corresponding range 53-90%). Correlation plots were constructed from the data for N2 fixed against crop dry matter yield and residual nitrogen benefit against nitrogen harvest index. Results are discussed in relation to values for N balance of field pea and other grain legumes obtained elsewhere by other investigators.

scholarly journals Crop performance, biological N fixation and pre-crop effect of pea ideotypes in an organic farming system

2019 ◽  
Vol 115 (3) ◽  
pp. 391-405 ◽  
Author(s):  
Gabriele Gollner ◽  
Walter Starz ◽  
Jürgen K. Friedel
Keyword(s):  
Grain Yield ◽  
Field Pea ◽  
N Balance ◽  
Grain Legume ◽  
Wheat Crop ◽  
N Fixation ◽  
Site Conditions ◽  
Organic Systems ◽  
Biological N Fixation ◽  
N Concentration

Abstract Pea (Pisum sativum L.) is a valuable grain legume in organic crop rotations. Pea rotations provide nitrogen (N) to the system through N fixation and produce animal feed or human food. Because of the high susceptibility of pea to pests, diseases and weeds and due to low profitability, especially in organic systems, pea cropping intensity decreased in the last 15 years in Austria. Therefore, it is important to find strategies for improving pea cropping systems in organic systems, by increasing yields and providing a positive N balance. The objective of this study was to compare pea genotypes of selected field and fodder pea in pure and mixed pea stands for biomass performance, biological N fixation and pre-crop effect under dry site conditions in a 2-year study in Eastern Austria. Pea N fixation was estimated using the extended N-difference method, with oat as the reference crop. The highest grain yield was found for the leafed field pea, with 2.5 Mg dry mass (DM) ha−1, followed by the semi-leafless field pea with 2.1 Mg DM ha−1 and the pea-mixtures with 2.2 Mg DM ha−1. The field pea cultivars yielded more than the fodder pea cultivars with 1.6 Mg DM ha−1. The average N concentration in pea grains was 3.6 mg g−1. The fodder pea type contained 3.8 mg g−1, significantly more N (p < 0.0001) than the semi-leafless and leafed field pea. Pea N fixation ranged from 53 to 75 kg N ha−1, corresponding to 42–50% of N derived from the atmosphere (% Ndfa). No differences in N fixation were found among cultivars, types and field/fodder pea. The fodder pea exported less N from the field because of their lower grain yield. Therefore, the N balance (N-input − N-output) of fodder pea was positive, with + 3.4 kg N ha−1 compared to the negative N balance of − 0.6 to − 3.6 kg N ha−1 for the leafed field pea types. These differences were not reflected in the following winter wheat crop, where the DM grain yield was 3.6–3.9 Mg ha−1 with no differences between cultivars and ideotypes. The results demonstrate that leafed field pea could have a sufficient grain yield and fodder pea could produce high N concentration in the grains. Because there are no differences regarding the effect of pea types on the yield of the following crop, it can be concluded that all tested pea types are suitable for successful organic pea production under dry site conditions. While there were no negative effects on the subsequent crop, the different ideotypes and mixtures may be selected based on different management goals.

Effects of grazing and depth on two wetland plant species

1994 ◽  
Vol 45 (8) ◽  
pp. 1387 ◽  
Author(s):  
SJ Blanch ◽  
MA Brock
Keyword(s):  
Morphological Changes ◽  
New South ◽  
Shoot Length ◽  
Water Levels ◽  
Growth Responses ◽  
Ground Biomass ◽  
South Wales ◽  
Shoot Production ◽  
Below Ground ◽  
Total Plant

Wetland plants in Llangothlin Lagoon, northern New South Wales, are subject to grazing and trampling by cattle, sheep and waterbirds and to fluctuating water levels. Myriophyllum variifolium J. Hooker, an aquatic dicotyledon with dispersed meristems, exhibited different morphological changes to the emergent monocotyledon Eleocharis acuta R. Br, under simulated and natural grazing at different water depths. Responses were principally determined by position and number of meristems. Growth point production (numbers of shoots and branches) increased under light, frequent clipping (25% every 14 or 7 days) in non-submerged plants only. Node production, total plant or shoot length, and above- and below-ground biomass decreased under similar clipping treatments. E. acuta did not increase shoot production or above-ground biomass under any clipping treatment, and only for the lightest clipping treatment (clipped once to 7 cm when non-submerged) was no decrease in total shoot length observed. More intense and frequent clipping treatments and submersion to 15 cm prevented both species from replacing lost tissues. Interaction between clipping and submersion occurred in both species, indicating that growth responses are complex. The distribution and abundance of the two species reflect the greater tolerance of M. variifolium than E. acuta to grazing and inundation. Low intensities of cattle and sheep grazing may be beneficial by increasing species diversity.

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

Use of in situ 15N-labelling to estimate the total below-ground nitrogen of pasture legumes in intact soil - plant systems

1997 ◽  
Vol 48 (3) ◽  
pp. 295 ◽  
Author(s):  
Ann M. McNeill ◽  
Chunya Zhu ◽  
Ian R. P. Fillery
Keyword(s):  
Subterranean Clover ◽  
Bulk Soil ◽  
Vegetative Stage ◽  
Residual Fraction ◽  
N Fixation ◽  
15N Labelling ◽  
Below Ground ◽  
Sampling Procedures ◽  
Intact Soil

A leaf-feeding technique for in situ 15N-labelling of intact soil–pasture plant systems was assessed, using subterranean clover (Trifolium subterraneum L.) and serradella (Ornithopus compressus L.) grown under glasshouse conditions. Total recoveries of fed 15N were 87–100% following leaf-feeding of plants at flowering but were lower (74–84%) following the feed at the vegetative stage. Below-ground recovery of fed 15N ranged from 7 to 26%, with serradella partitioning a greater proportion of labelled N below ground than subterranean clover. Additionally, plants of both species fed at the vegetative stage accumulated a greater proportion of the 15N label below ground than did those fed at flowering. Dry sampling procedures, which utilised freeze-drying, enabled fractionation of the below-ground portion of the system into ‘clean’ nodulated macro-roots with no adhering soil, residual uncleaned root, rhizosphere, and bulk soil. Calculated specific enrichment for the ‘clean’ roots at different depths demonstrated a relatively uniform distribution of 15N label in the subterranean clover roots, whereas the presence of large indeterminate nodules in the crown region of serradella roots contributed to apparent uneven distribution of label. Approximately half of the N in the residual fraction of both species consisted of labelled material, postulated to be mostly fine root. Additionally, 5–20% of the rhizosphere N and 0·5–3% of the N in bulk soil was legume root-derived, with some 15N detected in the extractable total soluble N and microbial N pools. Rhizodeposition of N represented approximately 10% of total plant N and 17–24% of total below-ground N for subterranean clover, whereas values for serradella were 20 and 34–37%, respectively. Estimated total below-ground N of subterranean clover reached a maximum value of 177 mg N/plant at 98 days after sowing, which corresponded with a peak shoot N of 243 mg N. Maximum below-ground N for serradella attained 196 mg N/plant 84 days after sowing with a corresponding shoot biomass of 225 mg N. There was a decline in the total below-ground N of serradella at maturity. Overall, recovered clean root N represented 30–62% of estimated total below-ground N, so it was concluded that standard root recovery procedures might be likely to underestimate severely the total below-ground N accretion and N turnover by legumes. The implications of these results for field estimation of total legume N yield, biological N fixation, and the N benefit from legumes in rotations are discussed.

scholarly journals Root biomass and root traits of Alnus glutinosa show size-dependent and opposite patterns in a drained and a rewetted forest peatland

2020 ◽  
Author(s):  
Sarah Schwieger ◽  
Gesche Blume-Werry ◽  
Felix Ciesiolka ◽  
Alba Anadon-Rosell
Keyword(s):  
Root Biomass ◽  
Environmental Changes ◽  
Alnus Glutinosa ◽  
Root Turnover ◽  
Functional Characteristics ◽  
Size Dependent ◽  
Root Age ◽  
C Stocks ◽  
Annual Growth Rings ◽  
Below Ground

Abstract Background and Aims Forest peatlands represent 25 % of global peatlands and store large amounts of carbon (C) as peat. Traditionally they have been drained in order to increase forestry yield, which may cause large losses of C from the peat. Rewetting aims to stop these losses and to restore the initial storage function of the peatlands. As roots represent major peat-forming elements in these systems, we sampled roots with diameter &lt;5 mm in a drained and a rewetted forest peatland in north-east Germany to evaluate differences in tree biomass investments below ground, root functional characteristics and root age. Methods We cored soil next to Alnus glutinosa stems and sorted root biomass into &lt;1, 1–2 and 2–5 mm diameter classes. We measured biomass distribution and specific root area (SRA) in 10-cm depth increments down to 50 cm, and estimated root age from annual growth rings. Key Results Root biomass in the rewetted site was more than double that in the drained site. This difference was mostly driven by very fine roots &lt;1 mm, which accounted for 51 % of the total root biomass and were mostly (75 %) located in the upper 20 cm. For roots &lt;1 mm, SRA did not differ between the sites. However, SRA of the 1–2 mm and 2–5 mm diameter roots was higher in the drained than in the rewetted site. Root age did not differ between sites. Conclusions The size-dependent opposite patterns between root biomass and their functional characteristics under contrasting water regimes indicate differences between fine and coarse roots in their response to environmental changes. Root age distribution points to similar root turnover rates between the sites, while higher root biomass in the rewetted site clearly indicates larger tree C stocks below ground under rewetting, supporting the C sink function of the ecosystem.

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.

scholarly journals High Below-Ground Productivity Allocation of Alpine Grasslands on the Northern Tibet

Plants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 535 ◽  
Author(s):  
Ben Niu ◽  
Chaoxu Zeng ◽  
Xianzhou Zhang ◽  
Yongtao He ◽  
Peili Shi ◽  
...  
Keyword(s):  
Alpine Meadow ◽  
Critical Parameters ◽  
Root Turnover ◽  
Desert Steppe ◽  
Meadow Steppe ◽  
Alpine Grasslands ◽  
Alpine Steppe ◽  
Northern Tibetan Plateau ◽  
Below Ground ◽  
Biomass Dynamics

The allocation of net primary production (NPP) between above- and belowground components is a key step of ecosystem material cycling and energy flows, which determines many critical parameters, e.g., the fraction of below ground NPP (BNPP) to NPP (fBNPP) and root turnover rates (RTR), in vegetation models. However, direct NPP estimation and partition are scarcely based on field measurements of biomass dynamics in the alpine grasslands on the Northern Tibetan Plateau (NTP). Consequently, these parameters are unverifiable and controversial. Here, we measured above- and belowground biomass dynamics (monthly from May to September each year from 2013 to 2015) to estimate NPP dynamics and allocations in four typical alpine grassland ecosystems, i.e., an alpine meadow, alpine meadow steppe, alpine steppe and alpine desert steppe. We found that NPP and its components, above and below ground NPP (ANPP and BNPP), increased significantly from west to east on the NTP, and ANPP was mainly affected by temperature while BNPP and NPP were mainly affected by precipitation. The bulk of BNPP was generally concentrated in the top 10 cm soil layers in all four alpine grasslands (76.1% ± 9.1%, mean ± SD). Our results showed that fBNPP was significantly different among these four alpine grasslands, with its means in alpine meadow (0.93), alpine desert steppe (0.92) being larger than that in the alpine meadow steppe (0.76) and alpine steppe (0.77). Both temperature and precipitation had significant and positive effects on the fBNPP, while their interaction effects were significantly opposite. RTR decreased with increasing precipitation, but increased with increasing temperature across this ecoregion. Our study illustrated that alpine grasslands on the NTP, especially in the alpine meadow and alpine desert steppe, partitioned an unexpected and greater NPP to below ground than most historical reports across global grasslands, indicating a more critical role of the root carbon pool in carbon cycling in alpine grasslands on the NTP.

scholarly journals Carbon and nutrient stocks in roots of forests at different altitudes in the Ecuadorian Andes

2007 ◽  
Vol 23 (3) ◽  
pp. 319-328 ◽  
Author(s):  
Nathalie Soethe ◽  
Johannes Lehmann ◽  
Christof Engels
Keyword(s):  
Fine Roots ◽  
Root Biomass ◽  
Plant Biomass ◽  
Coarse Roots ◽  
Nutrient Analysis ◽  
Tropical Montane Forests ◽  
Nutrient Stocks ◽  
Below Ground ◽  
Total Plant Biomass ◽  
Total Plant

Carbon and nutrient stocks in below-ground biomass have rarely been investigated in tropical montane forests. In the present study, the amounts of carbon, nitrogen, phosphorus, sulphur, potassium, calcium and magnesium in root biomass were determined by soil coring and nutrient analysis in forests at three altitudes (1900, 2400 and 3000 m) in the Ecuadorian Andes. Root biomass increased markedly from 2.8 kg m−2 at 1900 m and 4.0 kg m−2 at 2400 to 6.8 kg m−2 at 3000 m. The contribution of coarse roots (> 2 mm in diameter) to total root biomass increased from about 70% at 1900 m to about 80% at higher altitudes. In fine roots (≤ 2 mm in diameter), concentrations of nutrients except calcium markedly decreased with altitude. Therefore, the nutrient stocks in fine roots were similar at 1900 m and 3000 m for nitrogen and sulphur, and were even lower at higher altitudes for phosphorus, potassium and magnesium. In coarse roots of Graffenrieda emarginata concentrations of nutrients were substantially lower than in fine roots, and were little affected by altitude. The data suggest that the importance of coarse roots for long-term carbon and nutrient accumulation in total plant biomass increases with increasing altitude.

The nitrogen economy of broadacre lupin in southwest Australia

1994 ◽  
Vol 45 (1) ◽  
pp. 149 ◽  
Author(s):  
MJ Unkovich ◽  
JS Pate ◽  
J Hamblin
Keyword(s):  
N2 Fixation ◽  
Crop Residues ◽  
Nitrogen Accumulation ◽  
Study Region ◽  
South West ◽  
Peak Biomass ◽  
Below Ground ◽  
Southwest Australia ◽  
Total Plant ◽  
Time Courses

The time courses of above- and below-ground accumulation of biomass and N were followed in a crop of narrowleaf lupin (Lupinus angustifolius L. cv. Illyarrie) at Geraldton, W.A., and concurrent N2 fixation assessed using the 15N natural abundance technique. Crop biomass peaked at 10 t DM and 231 kg N ha-1 with 13% of this N below ground. The crop accumulated the bulk (90%) of its N through symbiotic N2 fixation. Of the 164 kg total plant N ha-1 remaining in recoverable biomass at maturity 44% was recovered as grain, 49% as other above-ground residues and 7% as roots. Despite a decrease in recoverable N of 67 kg ha-1 between peak biomass and maturity, 96 kg N ha-1 was returned as crop residues after grain harvest. Investigation of six farm crops in the study region gave values for nitrogen accumulation at peak biomass ranging from 199 to 372 kg ha-1 of which, on average, 86% (222 kg ha-1) was fixed from the atmosphere. Predicted N returns to the soil from fixation averaged 65 kg ha-1, though the range (32-96 kg ha-1) indicated that south-west Australian lupin crops provide somewhat variably sized pools of mineralizeable crop residues for following cereal growth.

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