scholarly journals The Contribution of Root Turnover on Biological Nitrification Inhibition and Its Impact on the Ammonia-Oxidizing Archaea under Brachiaria Cultivations

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1003 ◽  
Author(s):  
Satoshi Nakamura ◽  
Papa Sarr Saliou ◽  
Minako Takahashi ◽  
Yasuo Ando ◽  
Guntur Venkata Subbarao
Keyword(s):  
Root Tissue ◽  
Root Turnover ◽  
Nitrification Rate ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrification Inhibition ◽  
N Content ◽  
Available N ◽  
Ammonia Oxidizing Archaea ◽  
Potential Nitrification ◽  
Biological Nitrification

Aims: Biological nitrification inhibition (BNI) has been reported as an emerging technology to control soil nitrifier activity for effective N-utilization in cropping systems. Brachiaria have been reported to suppress nitrifier populations by releasing nitrification inhibitors from roots through exudation. Substantial BNI activity has been reported to be present in the root tissues of Brachiaria grasses; however, BNI contribution, such as root turnover, has not been addressed in previous studies. The present study aimed to clarify the contribution of root turnover on BNI under Brachiaria cultivations and its impact on nitrifier populations. Methods: We monitored root growth, changes in ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) numbers, nitrification rate, and available nitrogen (N) content under seven germplasm lines of Brachiaria, for 18 months with seasonal profile sampling. Results: Brachiaria cultivation increased soil NH4+-N, available N, and total soil carbon levels. Though we did not find any correlation between the changes in AOB populations and potential nitrification, the potential nitrification rate decreased when AOA populations decreased. Multiple regression analysis indicated that BNI substances from root tissue turnover had a significant contribution to the BNI function in the field. Conclusion Results indicated that the inhibitory effect of BNI was mostly evident in AOA, and not in AOB, in this study. Brachiaria cvs. ‘Marandu’, ‘Mulato’, and ‘Tupy’ had the most substantial BNI effect among the seven cultivars evaluated. The estimated total BNI activities and available N content of root tissue explained the observed nitrification inhibition. In conclusion, the release of BNI substances through plant decomposition contributes to the decrease in the abundance of AOA, and thus the inhibition of nitrification under Brachiaria cultivation.

scholarly journals Effectiveness of Nitrification Inhibition on Various Species of Brachiaria Grass Rhizosphere

2018 ◽  
Vol 31 ◽  
pp. 03007
Author(s):  
Purwanto ◽  
Supriyadi ◽  
Aniek Hindrayani
Keyword(s):  
Experimental Method ◽  
Soil Microbes ◽  
Environmentally Friendly ◽  
Nitrogen Utilization ◽  
N Fertilizer ◽  
Nitrification Rate ◽  
Nitrification Inhibition ◽  
Potential Nitrification ◽  
Randomized Design ◽  
Inhibition Of Nitrification

Nitrification has the potential to decrease the efficiency of nitrogen utilization by plants. The use of nitrifying inhibitory chemicals proved to be effective in controlling nitrification, but also affects beneficial soil microbes. Another attempt to inhibit the more environmentally-friendly nitrification is to use plants that have allelochemical nitrification inhibiting compounds such as the grasses of Brachiaria. The aim of this research is to know the effectivity of B.mutica, B.decumbens, and B.humidicola as inhibitors of nitrification rate in soil. The experiment was carried out by pot experimental method based on nondestructive sampling and Complete Randomized Design, consisting of Brachiaria plant types and various doses of N fertilizer, 100 kg/ha, 150 kg/ha, 200 kg/ha. The results of this study show that 1) B.mutica, B.decumbens, and B.humidicola, highly significant to the soil potential nitrification, but the treatment of various doses of N fertilizer is not significant to the soil potential nitrification. 2) the highest soil potential nitrification in B.mutica rhizosphere was 5.160 mg NO2-/g of soil/5h, while the lowest soil potential nitrification in the rhizosphere of B.humidicola plant was 0.414 mg NO2-/g/5h. 3) From the four treatment of Brachiaria plants can be concluded B.humidicola plant more effective in inhibition of nitrification.

scholarly journals Community Structure of Ammonia-Oxidizing Archaea and Ammonia-Oxidizing Bacteria in Soil Treated with the Insecticide Imidacloprid

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Mariusz Cycoń ◽  
Zofia Piotrowska-Seget
Keyword(s):  
Community Structure ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Wiener Index ◽  
Nitrification Rate ◽  
Ammonia Oxidizing Bacteria ◽  
Community Members ◽  
Insecticide Treatment ◽  
Soil Nitrification ◽  
Ammonia Oxidizing Archaea ◽  
Gradient Gel Electrophoresis

The purpose of this experiment was to assess the effect of imidacloprid on the community structure of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in soil using the denaturing gradient gel electrophoresis (DGGE) approach. Analysis showed that AOA and AOB community members were affected by the insecticide treatment. However, the calculation of the richness (S) and the Shannon-Wiener index (H) values for soil treated with the field rate (FR) dosage of imidacloprid (1 mg/kg soil) showed no changes in measured indices for the AOA and AOB community members. In turn, the10*FRdosage of insecticide (10 mg/kg soil) negatively affected the AOA community, which was confirmed by the decrease of theSandHvalues in comparison with the values obtained for the control soil. In the case of AOB community, an initial decline followed by the increase of theSandHvalues was obtained. Imidacloprid decreased the nitrification rate while the ammonification process was stimulated by the addition of imidacloprid. Changes in the community structure of AOA and AOB could be due to an increase in the concentration of N-NH4+, known as the most important factor which determines the contribution of these microorganisms to soil nitrification.

scholarly journals Contingent Effects of Liming on N2O-Emissions Driven by Autotrophic Nitrification

2020 ◽  
Vol 8 ◽  
Author(s):  
Shahid Nadeem ◽  
Lars R. Bakken ◽  
Åsa Frostegård ◽  
John C. Gaby ◽  
Peter Dörsch
Keyword(s):  
Field Experiments ◽  
Pore Space ◽  
Abundance Ratio ◽  
Nitrification Rate ◽  
N2o Emissions ◽  
Ammonia Oxidizing Bacteria ◽  
Product Ratio ◽  
Potential Nitrification ◽  
Aerobic Soil ◽  
Heterotrophic Denitrification

Liming acidic soils is often found to reduce their N2O emission due to lowered N2O/(N2O + N2) product ratio of denitrification. Some field experiments have shown the opposite effect, however, and the reason for this could be that liming stimulates nitrification-driven N2O production by enhancing nitrification rates, and by favoring ammonia oxidizing bacteria (AOB) over ammonia oxidizing archaea (AOA). AOB produce more N2O than AOA, and high nitrification rates induce transient/local hypoxia, thereby stimulating heterotrophic denitrification. To study these phenomena, we investigated nitrification and denitrification kinetics and the abundance of AOB and AOA in soils sampled from a field experiment 2–3 years after liming. The field trial compared traditional liming (carbonates) with powdered siliceous rocks. As expected, the N2O/(N2O + N2) product ratio of heterotrophic denitrification declined with increasing pH, and the potential nitrification rate and its N2O yield (YN2O: N2O-N/NO3–-N), as measured in fully oxic soil slurries, increased with pH, and both correlated strongly with the AOB/AOA gene abundance ratio. Soil microcosm experiments were monitored for nitrification, its O2-consumption and N2O emissions, as induced by ammonium fertilization. Here we observed a conspicuous dependency on water filled pore space (WFPS): at 60 and 70% WFPS, YN2O was 0.03-0.06% and 0.06–0.15%, respectively, increasing with increasing pH, as in the aerobic soil slurries. At 85% WFPS, however, YN2O was more than two orders of magnitude higher, and decreased with increasing pH. A plausible interpretation is that O2 consumption by fertilizer-induced nitrification cause hypoxia in wet soils, hence induce heterotrophic nitrification, whose YN2O decline with increasing pH. We conclude that while low emissions from nitrification in well-drained soils may be enhanced by liming, the spikes of high N2O emission induced by ammonium fertilization at high soil moisture may be reduced by liming, because the heterotrophic N2O reduction is enhanced by high pH.

scholarly journals Biological nitrification inhibition by root exudates of native species,Hibiscus splendensandSolanum echinatum

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4960 ◽  
Author(s):  
Chelsea K. Janke ◽  
Laura A. Wendling ◽  
Ryosuke Fujinuma
Keyword(s):  
Plant Species ◽  
Root Exudates ◽  
Native Species ◽  
N Uptake ◽  
Nitrification Inhibition ◽  
Native Plant ◽  
Native Plant Species ◽  
Potential Nitrification ◽  
Australian Native Plant ◽  
Biological Nitrification

Australian native species grow competitively in nutrient limited environments, particularly in nitrogen (N) limited soils; however, the mechanism that enables this is poorly understood. Biological nitrification inhibition (BNI), which is the release of root exudates into the plant rhizosphere to inhibit the nitrification process, is a hypothesized adaptive mechanism for maximizing N uptake. To date, few studies have investigated the temporal pattern and components of root exudates by Australian native plant species for BNI. This study examined root exudates from two Australian native species,Hibiscus splendensandSolanum echinatum,and contrasted with exudates ofSorghum bicolor, a plant widely demonstrated to exhibit BNI capacity. Root exudates were collected from plants at two, four, and six weeks after transplanting to solution culture. Root exudates contained three types of organic acids (OAs), oxalic, citric and succinic acids, regardless of the species. However, the two Australian natives species released larger amount of OAs in earlier development stages thanS. bicolor. The total quantity of these OAs released per unit root dry mass was also seven-ten times greater for Australian native plant species compared toS. bicolor. The root exudates significantly inhibited nitrification activity over six weeks’ growth in a potential nitrification assay, withS. echinatum(ca. 81% inhibition) >S. bicolor(ca. 80% inhibition) >H. splendens(ca. 78% inhibition). The narrow range of BNI capacity in the study plants limited the determination of a relationship between OAs and BNI; however, a lack of correlation between individual OAs and inhibition of nitrification suggests OAs may not directly contribute to BNI. These results indicate that Australian native species generate a strongly N conserving environment within the rhizosphere up to six weeks after germination, establishing a competitive advantage in severely N limited environments.

scholarly journals Effects of Phosphorus on Nitrification Process in a Fertile Soil Amended with Urea

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 523
Author(s):  
Jianfeng Ning ◽  
Yuji Arai ◽  
Jian Shen ◽  
Ronghui Wang ◽  
Shaoying Ai
Keyword(s):  
Nutrient Management ◽  
N:P Ratio ◽  
Nitrification Rate ◽  
Ammonia Oxidizing Bacteria ◽  
N Losses ◽  
N Cycle ◽  
Ammonia Oxidizing Archaea ◽  
Nitrification Process ◽  
Monopotassium Phosphate ◽  
P Addition

While the effects of carbon on soil nitrogen (N) cycle have been extensively studied, it is not clearly understood how co-existing macronutrients, such as phosphorus (P), affect the N cycle in agroecosystems. In this study, P amendment effects on nitrification in a fertile agricultural soil were investigated under a typical N-P amendment rate. In a laboratory incubation study, soils were amended with urea, monopotassium phosphate and a mixture of urea and monopotassium phosphate at the same rate. In soils that received no amendments (control), P only, urea only, and urea plus P amendment, nitrification occurred within the first five days, with an average net nitrification rate of 5.30, 5.77, 16.66 and 9.00 mg N kg−1d−1, respectively. Interestingly, nitrification in urea-treated soils was retarded by P addition where a N:P ratio seemed to be a key factor impeding nitrification. This was also supported by the response of ammonia-oxidizing bacteria (AOB), which was more sensitive to P addition than ammonia-oxidizing archaea (AOA). The outcome of this study showed that application of P fertilizer suppressed the nitrification process in urea amended soil, suggesting that a synergistic aspect of N and P nutrient management should be further explored to retard N losses from agricultural systems.

How sequential reduction of terminal electron acceptors modulates nitrification and dynamics of nitrifying bacteria and archaea in a tropical vertisol

2018 ◽  
Vol 156 (2) ◽  
pp. 215-224
Author(s):  
Santosh Ranjan Mohanty ◽  
Rakhi Yadav ◽  
Garima Dubey ◽  
Usha Ahirwar ◽  
Neha Ahirwar ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Principal Component ◽  
Electron Acceptors ◽  
Nitrifying Bacteria ◽  
Nitrification Rate ◽  
Ammonia Oxidizing Bacteria ◽  
Linear Regression Models ◽  
Reducing Conditions ◽  
Potential Nitrification ◽  
Sequential Reduction

AbstractNitrification potential of a tropical vertisol saturated with water was estimated during sequential reduction of nitrate (NO3−), ferric iron (Fe3+), sulphate (SO42−) and carbon dioxide (CO2) in terminal electron-accepting processes (TEAPs). In general, the TEAPs enhanced potential nitrification rate (PNR) of the soil. Nitrification was highest at Fe3+reduction followed by SO42−reduction, NO3−reduction and lowest in unreduced control soil. Predicted PNR correlated significantly with the observed PNR. Electron donor Fe2+stimulated PNR, while S2−inhibited it significantly. Terminal-restriction fragment length polymorphism targeting theamoAgene of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) highlighted population dynamics during the sequential reduction of terminal electron acceptors. Only the relative abundance of AOA varied significantly during the course of soil reduction. Relative abundance of AOB correlated with NO3−and Fe2+. Linear regression models predicted PNR from the values of NO3−, Fe2+and relative abundance of AOA. Principal component analysis of PNR during different reducing conditions explained 72.90% variance by PC1 and 19.52% variance by PC2. Results revealed that AOA might have a significant role in nitrification during reducing conditions in the tropical flooded ecosystem of a vertisol.

scholarly journals Ammonium Availability Affects the Ratio of Ammonia-Oxidizing Bacteria to Ammonia-Oxidizing Archaea in Simulated Creek Ecosystems

2011 ◽  
Vol 77 (5) ◽  
pp. 1896-1899 ◽  
Author(s):  
Martina Herrmann ◽  
Andrea Scheibe ◽  
Sharon Avrahami ◽  
Kirsten Küsel
Keyword(s):  
Microbial Community ◽  
Incubation Period ◽  
Gene Copy ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonia Oxidizing Archaea ◽  
Flow Channels ◽  
Copy Numbers ◽  
Potential Nitrification ◽  
Gene Copy Numbers ◽  
Clay Tiles

ABSTRACTThe ammonia-oxidizing microbial community colonizing clay tiles in flow channels changed in favor of ammonia-oxidizing bacteria during a 12-week incubation period even at originally high ratios of ammonia-oxidizing archaea to ammonia-oxidizing bacteria (AOB). AOB predominance was established more rapidly in flow channels incubated at 350 μM NH4+than in those incubated at 50 or 20 μM NH4+. Biofilm-associated potential nitrification activity was first detected after 28 days and was positively correlated with bacterial but not archaealamoAgene copy numbers.

scholarly journals Ammonia-oxidizing archaea are integral to nitrogen cycling in a highly fertile agricultural soil

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Laibin Huang ◽  
Seemanti Chakrabarti ◽  
Jennifer Cooper ◽  
Ana Perez ◽  
Sophia M. John ◽  
...  
Keyword(s):  
Nitrogen Cycle ◽  
Agricultural Soil ◽  
Agricultural Soils ◽  
Ammonia Oxidizing Bacteria ◽  
Central Process ◽  
Soil Nitrification ◽  
Plant Nitrogen ◽  
Ammonia Oxidizing Archaea ◽  
Activity Measurements ◽  
Nitrite Oxidizing Bacteria

AbstractNitrification is a central process in the global nitrogen cycle, carried out by a complex network of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), complete ammonia-oxidizing (comammox) bacteria, and nitrite-oxidizing bacteria (NOB). Nitrification is responsible for significant nitrogen leaching and N2O emissions and thought to impede plant nitrogen use efficiency in agricultural systems. However, the actual contribution of each nitrifier group to net rates and N2O emissions remain poorly understood. We hypothesized that highly fertile agricultural soils with high organic matter mineralization rates could allow a detailed characterization of N cycling in these soils. Using a combination of molecular and activity measurements, we show that in a mixed AOA, AOB, and comammox community, AOA outnumbered low diversity assemblages of AOB and comammox 50- to 430-fold, and strongly dominated net nitrification activities with low N2O yields between 0.18 and 0.41 ng N2O–N per µg NOx–N in cropped, fallow, as well as native soil. Nitrification rates were not significantly different in plant-covered and fallow plots. Mass balance calculations indicated that plants relied heavily on nitrate, and not ammonium as primary nitrogen source in these soils. Together, these results imply AOA as integral part of the nitrogen cycle in a highly fertile agricultural soil.

scholarly journals Biological nitrification inhibition in maize—isolation and identification of hydrophobic inhibitors from root exudates

2021 ◽  
Author(s):  
Junnosuke Otaka ◽  
Guntur Venkata Subbarao ◽  
Hiroshi Ono ◽  
Tadashi Yoshihashi
Keyword(s):  
Root Exudation ◽  
Root Systems ◽  
Root Surface ◽  
Maize Root ◽  
Nitrification Inhibition ◽  
Isolation And Identification ◽  
N Losses ◽  
Chemical Structures ◽  
Maize Roots ◽  
Biological Nitrification

AbstractTo control agronomic N losses and reduce environmental pollution, biological nitrification inhibition (BNI) is a promising strategy. BNI is an ecological phenomenon by which certain plants release bioactive compounds that can suppress nitrifying soil microbes. Herein, we report on two hydrophobic BNI compounds released from maize root exudation (1 and 2), together with two BNI compounds inside maize roots (3 and 4). On the basis of a bioassay-guided fractionation method using a recombinant nitrifying bacterium Nitrosomonas europaea, 2,7-dimethoxy-1,4-naphthoquinone (1, ED50 = 2 μM) was identified for the first time from dichloromethane (DCM) wash concentrate of maize root surface and named “zeanone.” The benzoxazinoid 2-hydroxy-4,7-dimethoxy-2H-1,4-benzoxazin-3(4H)-one (HDMBOA, 2, ED50 = 13 μM) was isolated from DCM extract of maize roots, and two analogs of compound 2, 2-hydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (HMBOA, 3, ED50 = 91 μM) and HDMBOA-β-glucoside (4, ED50 = 94 μM), were isolated from methanol extract of maize roots. Their chemical structures (1–4) were determined by extensive spectroscopic methods. The contributions of these four isolated BNI compounds (1–4) to the hydrophobic BNI activity in maize roots were 19%, 20%, 2%, and 4%, respectively. A possible biosynthetic pathway for zeanone (1) is proposed. These results provide insights into the strength of hydrophobic BNI activity released from maize root systems, the chemical identities of the isolated BNIs, and their relative contribution to the BNI activity from maize root systems.

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