Alteration of size of wheat root systems and nitrogen fixation by associative nitrogen-fixing bacteria measured under field conditions

1988 ◽  
Vol 34 (6) ◽  
pp. 735-739 ◽  
Author(s):  
R. M. N. Kucey
Keyword(s):  
Plant Root ◽  
N Uptake ◽  
Wheat Plant ◽  
Root Systems ◽  
System Size ◽  
Wheat Root ◽  
Field Conditions ◽  
Total N ◽  
Matter Production ◽  
And Control

Spring wheat was inoculated with Azospirillum brasilense Cd or Bacillus C-11-25 under field conditions. Use of a 32P measuring technique showed that the root systems of Azospirillum-inoculated wheat occupied 54% of the soil volumes compared with uninoculated wheat plant root systems. Bacillus-inoculated wheat root systems were 82% of the size of uninoculated wheat root systems. Inoculated and control plants did not differ in dry matter production or in total N content. Inoculated plants received between 5 and 10% of the N contained in their tissues from associative N2 fixation as measured by 15N isotope dilution. Reduction of root system size in inoculated plants explains how the inoculated wheat plants in this study, and in previously reported studies, are able to absorb atmospheric N2 via associative N2 fixation without increasing total plant N uptake.

scholarly journals Aluminum and Phosphorus Interactions in Mycorrhizal and Nonmycorrhizal Highbush Blueberry Plantlets

1997 ◽  
Vol 122 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Wei Qiang Yang ◽  
Barbara L. Goulart
Keyword(s):  
Plant Root ◽  
N Uptake ◽  
Dry Mass ◽  
Vaccinium Corymbosum ◽  
P Uptake ◽  
Highbush Blueberry ◽  
Mycorrhizal Infection ◽  
Negative Effects ◽  
Matter Production ◽  
Al Uptake

Aluminum (Al) and phosphorus (P) interactions were investigated in mycorrhizal (M) and nonmycorrhizal (NM) highbush blueberry (Vaccinium corymbosum L.) plantlets in a factorial experiment. The toxic effects of Al on highbush blueberry were characterized by decreased shoot, root, and total plant dry mass. Many of the negative effects of Al on plant root, shoot, and total dry matter production were reversed by foliar P and N application, indicating P or N uptake were limited by high Al concentration. However, Al-mediated growth reduction in P-stressed plants indicated that the restriction of P uptake by high Al may not have been the only mechanism for Al toxicity in this experiment. Root Al and P concentration were negatively correlated in NM but not M plantlets, suggesting mycorrhizal infection may alter P uptake processes. Al uptake was also affected by mycorrhizal infection, with more Al accumulating in M plantlet roots and leaves. Correlations among foliar ion concentrations were also affected by mycorrhizal fungal infection.

scholarly journals An automatic segmentation method for scanned images of wheat root systems with dark discolourations

2009 ◽  
Vol 19 (4) ◽  
pp. 679-689 ◽  
Author(s):  
Jarosław Gocławski ◽  
Joanna Sekulska-Nalewajko ◽  
Ewa Gajewska ◽  
Marzena Wielanek
Keyword(s):  
Plant Root ◽  
Automatic Segmentation ◽  
Root Systems ◽  
Wheat Root ◽  
Health State ◽  
Segmentation Method ◽  
Wheat Roots ◽  
Fuzzy C Means Clustering ◽  
Scanned Images ◽  
Plant Root System

An automatic segmentation method for scanned images of wheat root systems with dark discolourationsThe analysis of plant root system images plays an important role in the diagnosis of plant health state, the detection of possible diseases and growth distortions. This paper describes an initial stage of automatic analysis—the segmentation method for scanned images of Ni-treated wheat roots from hydroponic culture. The main roots of a wheat fibrous system are placed separately in the scanner view area on a high chroma background (blue or red). The first stage of the method includes the transformation of a scanned RGB image into the HCI (Hue-Chroma-Intensity) colour space and then local thresholding of the chroma component to extract a binary root image. Possible chromatic discolourations, different from background colour, are added to the roots from blue or red chroma subcomponent images after thresholding. At the second stage, dark discolourations are extracted by local fuzzy c-means clustering of an HCI intensity image within the binary root mask. Fuzzy clustering is applied in local windows around the series of sample points on roots medial axes (skeleton). The performance of the proposed method is compared with hand-labelled segmentation for a series of several root systems.

scholarly journals Aluminum and Phosphorus Interactions in Mycorrhizal and Nonmycorrhizal Highbush Blueberry Plantlets

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 672a-672
Author(s):  
Wei Qiang Yang ◽  
Barbara L. Goulart ◽  
Kathleen Demchak
Keyword(s):  
Plant Root ◽  
N Uptake ◽  
Dry Weight ◽  
P Uptake ◽  
Highbush Blueberry ◽  
Negative Effects ◽  
N Application ◽  
Matter Production ◽  
Al Uptake ◽  
Total Plant

Aluminum and P interactions were investigated in mycorrhizal (M) and nonmycorrhizal (NM) highbush blueberry plantlets in a factorial experiment. The toxic effects of Al on highbush blueberry were characterized by decreased shoot, root, and total plant dry weight. Many of the negative effects of Al on plant root, shoot, and total dry-matter production were reversed by foliar P and N application, indicating P or N uptake were limited by high Al concentration. However, Al mediated growth reduction in P-stressed plants suggested that the restriction of P uptake by high Al may not have been the only mechanism for Al toxicity in this experiment. Root Al and P concentration were negatively correlated in NM plantlets but not in M plantlets, suggesting mycorrhizal infection may alter P uptake processes. Al uptake also was affected by M infection, with more Al accumulating in M plantlet roots and leaves. Correlations among foliar ion concentrations were also affected by M fungal infection.

Nitrate and water uptake, rather than rhizodeposition, control denitrification in the presence of growing plants

2021 ◽  
Author(s):  
Pauline Sophie Rummel ◽  
Reinhard Well ◽  
Birgit Pfeiffer ◽  
Klaus Dittert ◽  
Sebastian Floßmann ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Uptake ◽  
Plant Root ◽  
Oxygen Deficiency ◽  
N Uptake ◽  
Root Exudation ◽  
Root Systems ◽  
Plant N Uptake ◽  
N Losses ◽  
Double Labeling

<p>The main prerequisites for denitrification are availability of nitrate (NO<sub>3</sub><sup>-</sup>) and easily decomposable organic substances, and oxygen deficiency. Growing plants modify all these parameters and may thus play an important role in regulating denitrification. Previous studies investigating plant root effects on denitrification have found contradictive results. Both increased and decreased denitrification in the presence of plants have been reported and were associated with higher C<sub>org</sub> or lower NO<sub>3</sub><sup>-</sup> availability, respectively. Accordingly, it is still unclear whether growing plants stimulate denitrification through root exudation or restrict it through NO<sub>3</sub><sup>-</sup> uptake. Furthermore, reliable measurements of N<sub>2</sub> fluxes and N<sub>2</sub>O/(N<sub>2</sub>O+N<sub>2</sub>) ratios in the presence of plants are scarce.</p><p>Therefore, we conducted a double labeling pot experiment with either maize (<em>Zea mays</em> L.) or cup plant (<em>Silphium perfoliatum</em> L.) of the same age but differing in size of their shoot and root systems. The <sup>15</sup>N gas flux method was applied to directly quantify N<sub>2</sub>O and N<sub>2</sub> fluxes in situ. To link denitrification with available C in the rhizosphere, <sup>13</sup>CO<sub>2</sub> pulse labeling was used to trace C translocation from shoots to roots and its release by roots into the soil.</p><p>Plant water uptake was a main factor controlling soil moisture and, thus, daily N<sub>2</sub>O+N<sub>2</sub> fluxes, cumulative N emissions, and N<sub>2</sub>O production pathways. However, N fluxes remained on a low level when NO<sub>3</sub><sup>-</sup> availability was low due to rapid plant N uptake. Only when both N and water uptake were low, high NO<sub>3</sub><sup>-</sup> availability and high soil moisture led to strongly increased denitrification-derived N losses.</p><p>Total CO<sub>2</sub> efflux was positively correlated with root dry matter, but there was no indication of any relationship between recovered <sup>13</sup>C from root exudation and cumulative N emissions. We anticipate that higher C<sub>org</sub> availability in pots with large root systems did not lead to higher denitrification rates, as NO<sub>3</sub><sup>-</sup> was limiting denitrification due to plant N uptake. Overall, we conclude that root-derived C stimulates denitrification only when soil NO<sub>3</sub><sup>-</sup> is not limited and low O<sub>2</sub> concentrations enable denitrification. Thus, root-derived C may stimulate denitrification under small plants, while N and water uptake become the controlling factors with increasing plant and root growth.</p>

Using advanced control, post-denitrification and equalisation to improve the performance of a submerged filter

2000 ◽  
Vol 41 (4-5) ◽  
pp. 177-184 ◽  
Author(s):  
K.H. Sørensen ◽  
D. Thornberg ◽  
K.F. Janning
Keyword(s):  
Energy Consumption ◽  
Total N ◽  
Control Loops ◽  
Effluent Quality ◽  
Advanced Control ◽  
Before And After ◽  
And Control ◽  
Side Flow ◽  
Configuration Control ◽  
Control Post

In 1998, the capacity of the BIOSTYR® submerged biofilter at Nyborg WWTP was extended from 48,000 PE to 60,000 PE including advanced sensor based control, post-denitrification in BIOSTYR® and equalization of side flows. The existing configuration with 8 BIOSTYR® DN/N cells is based on pre-denitrification and an internal recirculation of 600–800%. The extended plant comprises 7 BIOSTYR® DN/N cells with 50–225% recirculation followed by 3 BIOSTYR DN cells for post-denitrification. The advanced control loops include blower control, control of the number of active cells (stand-by), automatic switch to high load configuration, control of the side flow equalization, control of the internal recirculation and control of the external carbon source dosing. In this paper, the achieved improvements are documented by comparing influent and effluent data, methanol and energy consumption from comparable periods before and after the extension. Although the nitrogen load to the plant was increased by 20% after the extension, the effluent quality has improved significantly with a reduction of Total-N from 7–8 mg/l to 3–4 mg/l. Simultaneously, the methanol consumption has been reduced by more than 50% per kg removed nitrogen. The energy consumption remained constant although the nitrogen load was increased by 20% and the inflow by 80%.

scholarly journals Biochar and urease inhibitor mitigate NH3 and N2O emissions and improve wheat yield in a urea fertilized alkaline soil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Khadim Dawar ◽  
Shah Fahad ◽  
M. M. R. Jahangir ◽  
Iqbal Munir ◽  
Syed Sartaj Alam ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Grain Yield ◽  
Block Design ◽  
N Uptake ◽  
Nitrous Oxide Emissions ◽  
N2o Emissions ◽  
Urease Inhibitor ◽  
Alkaline Soil ◽  
Total N ◽  
N Assimilation

AbstractIn this study, we explored the role of biochar (BC) and/or urease inhibitor (UI) in mitigating ammonia (NH3) and nitrous oxide (N2O) discharge from urea fertilized wheat cultivated fields in Pakistan (34.01°N, 71.71°E). The experiment included five treatments [control, urea (150 kg N ha−1), BC (10 Mg ha−1), urea + BC and urea + BC + UI (1 L ton−1)], which were all repeated four times and were carried out in a randomized complete block design. Urea supplementation along with BC and BC + UI reduced soil NH3 emissions by 27% and 69%, respectively, compared to sole urea application. Nitrous oxide emissions from urea fertilized plots were also reduced by 24% and 53% applying BC and BC + UI, respectively, compared to urea alone. Application of BC with urea improved the grain yield, shoot biomass, and total N uptake of wheat by 13%, 24%, and 12%, respectively, compared to urea alone. Moreover, UI further promoted biomass and grain yield, and N assimilation in wheat by 38%, 22% and 27%, respectively, over sole urea application. In conclusion, application of BC and/or UI can mitigate NH3 and N2O emissions from urea fertilized soil, improve N use efficiency (NUE) and overall crop productivity.

scholarly journals Combined application of biochar with fertilizer promotes nitrogen uptake in maize by increasing nitrogen retention in soil

Biochar ◽  
2021 ◽  
Author(s):  
Jing Peng ◽  
Xiaori Han ◽  
Na Li ◽  
Kun Chen ◽  
Jinfeng Yang ◽  
...  
Keyword(s):  
Crop Yield ◽  
N Uptake ◽  
Nitrogen Retention ◽  
N Recovery ◽  
Chemical Fertilizers ◽  
Total N ◽  
Residual Rate ◽  
The Third ◽  
Combined Application ◽  
Entire Experiment

AbstractCombined application of biochar with fertilizers has been used to increase soil fertility and crop yield. However, the coupling mechanisms through which biochar improves crop yield at field scale and the time span over which biochar affects carbon and nitrogen transformation and crop yield are still little known. In this study, a long-term field trial (2013–2019) was performed in brown soil planting maize. Six treatments were designed: CK—control; NPK—application of chemical fertilizers; C1PK—low biochar without nitrogen fertilizer; C1NPK, C2NPK and C3NPK—biochar at 1.5, 3 and 6 t ha−1, respectively, combined with chemical fertilizers. Results showed that the δ15N value in the topsoil of 0–20 cm layer in the C3NPK treatment reached a peak of 291 ‰ at the third year (2018), and demonstrated a peak of 402 ‰ in the NPK treatment in the initial isotope trial in 2016. Synchronously, SOC was not affected until the third to fourth year after biochar addition, and resulted in a significant increase in total N of 2.4 kg N ha−1 in 2019 in C3NPK treatment. During the entire experiment, the 15N recovery rates of 74–80% were observed highest in the C2NPK and C3NPK treatments, resulting in an annual increase in yields significantly. The lowest subsoil δ15N values ranged from 66‰ to 107‰, and the 15N residual rate would take 70 years for a complete decay to 0.001% in the C3NPK. Our findings suggest that biochar compound fertilizers can increase C stability and N retention in soil and improve N uptake by maize, while the loss of N was minimized. Biochars, therefore, may have an important potential for improving the agroecosystem and ecological balance. Graphic abstract

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