Proceedings available at: http://www.extension.org/67590
Soil microbial communities have been proposed as indicators of soil quality due to their importance as drivers of global biogeochemical cycles and their sensitivity to management and climatic conditions. Despite the importance of the soil microbiota to nutrient transformation and chemical cycling, physio-chemical properties rather than biological properties of soils are traditionally used as measures of environmental status. In general, much is unknown regarding the effect of management fluctuations on important functional groups in soils systems (i.e., methanogens, nitrifiers and denitrifiers). It is only recently that it has been possible, through application of sophisticated molecular microbiological methods, to sensitively and specifically target important microbial populations that contribute to nutrient cycling and plant health present at the field-scale and in differentially managed soil systems.
Introduction to ArtificiaI Intelligence in Higher Education
Influence of Swine Manure Application Method on Concentrations of Methanogens and Denitrifiers in Agricultural Soils
1. Influence of Swine Manure ApplicationInfluence of Swine Manure Application
Method on Concentrations of MethanogensMethod on Concentrations of Methanogens
and Denitrifiers in Agricultural Soilsand Denitrifiers in Agricultural Soils
Kimberly Cook & Karamat SistaniKimberly Cook & Karamat Sistani
Bowling Green, KYBowling Green, KY
2. Microbes & Biogeochemical CyclesMicrobes & Biogeochemical Cycles
Indicators of soil qualityIndicators of soil quality
Drivers of global biogeochemical cyclesDrivers of global biogeochemical cycles
Sensitive to soil managementSensitive to soil management
Sensitive to climate conditionsSensitive to climate conditions
Physical vs BiologicalPhysical vs Biological
Traditional measures focused on physio-chemicalTraditional measures focused on physio-chemical
Molecular methods contribute to microbial analysesMolecular methods contribute to microbial analyses
Better understand relationship between physical,Better understand relationship between physical,
chemical and biological processes in agriculturalchemical and biological processes in agricultural
systemssystems
3. Microbes & GHGMicrobes & GHG
Major Ag associated GHG: COMajor Ag associated GHG: CO22,,CHCH44 & N& N22OO
Bacteria are largest producers of methane andBacteria are largest producers of methane and
NN22OO
Methane productionMethane production
Complex anaerobic consortiaComplex anaerobic consortia
Fermentative bacteria & methanogenic archaeaFermentative bacteria & methanogenic archaea
Livestock and soilsLivestock and soils
Anaerobic manure management systemsAnaerobic manure management systems
NN22O from denitrification (anaerobic) andO from denitrification (anaerobic) and
nitrification (anaerobic)nitrification (anaerobic)
4.
5. Cause & EffectCause & Effect
How does management or environment affectHow does management or environment affect
GHG production?GHG production?
How does management or environment affectHow does management or environment affect
bacteria that producebacteria that produce GHG?GHG?
6. Swine Effluent Application StudySwine Effluent Application Study
Evaluate the effect of pre-plant swine effluentEvaluate the effect of pre-plant swine effluent
application method on GHG (COapplication method on GHG (CO22 ,CH,CH44 & N& N22O)O)
emissions from soil in a no-till corn grainemissions from soil in a no-till corn grain
production systemproduction system
Sistani, K.R., Warren, J.G., Lovanh, N.C.,Sistani, K.R., Warren, J.G., Lovanh, N.C.,
Higgins, S., Shearer, S. 2010. Green House GasHiggins, S., Shearer, S. 2010. Green House Gas
Emissions from Swine Effluent Applied to SoilEmissions from Swine Effluent Applied to Soil
by Different Methods. Soil Sci. America J. 74(2):by Different Methods. Soil Sci. America J. 74(2):
429-435.429-435.
7. MethodsMethods
Two growing seasons of no-till cornTwo growing seasons of no-till corn
Gases measured using vented chambersGases measured using vented chambers
Three effluent application methodsThree effluent application methods
SurfaceSurface
Direct InjectionDirect Injection
Plus AerationPlus Aeration
Microbiology – one sample point 2 weeks afterMicrobiology – one sample point 2 weeks after
application in 2008application in 2008
10. COCO22 production similarproduction similar
in all treatmentsin all treatments
No influence of swineNo influence of swine
effluent applicationeffluent application
11. Total bacterial cell numbers similar in all treatmentsTotal bacterial cell numbers similar in all treatments
Total fungal cell numbers similar in all treatmentsTotal fungal cell numbers similar in all treatments
Averaged 3 orders of magnitude lower than total cellsAveraged 3 orders of magnitude lower than total cells
12. CHCH44 higher in injectionhigher in injection
treatmenttreatment
Emissions spiked for up toEmissions spiked for up to
11 days after application11 days after application
13. Concentrations of methanogens (Concentrations of methanogens (mcrAmcrA) were up to) were up to
7 orders of higher than background7 orders of higher than background
Methane oxidizers (Methane oxidizers (pmoApmoA) were up to 6 orders of) were up to 6 orders of
magnitude highermagnitude higher
14. NN22O flux highest in injectionO flux highest in injection
treatmenttreatment
Peak in flux at 6 dPeak in flux at 6 d
However, aeration & injectionHowever, aeration & injection
treatments continued totreatments continued to
increase & peaked after 18 dincrease & peaked after 18 d
20. ConclusionsConclusions
Two groups showed significant response toTwo groups showed significant response to
effluent applicationeffluent application
Nitrifying Bacteria (AOB)Nitrifying Bacteria (AOB)
Nitrate Reducers (Nitrate Reducers (narGnarG))
Methanogens and methane oxidizers alsoMethanogens and methane oxidizers also
increased orders of magnitude but were broughtincreased orders of magnitude but were brought
in with slurryin with slurry
Sampling method, targeted genes and analysisSampling method, targeted genes and analysis
method are all significantmethod are all significant
21. Integrating MicrobiologyIntegrating Microbiology
Integrate into field analyses; incorporateIntegrate into field analyses; incorporate
thinking into management practicesthinking into management practices
Biological perspectiveBiological perspective
Enzyme dependent pHEnzyme dependent pH
Requirement for co-factorsRequirement for co-factors
Mitigation of NMitigation of N22OO in atmosphere exclusively
carried out by nitrous oxide reducers (nosZ)nitrous oxide reducers (nosZ)
Requires 12 Copper ionsRequires 12 Copper ions
Optimum pH over 7Optimum pH over 7
22. CollaboratorsCollaborators
Special thanks to Dr. Jason Warren (OK StateSpecial thanks to Dr. Jason Warren (OK State
University) for collaborative efforts on thisUniversity) for collaborative efforts on this
projectproject
Thanks also to Rohan Parekh and JasonThanks also to Rohan Parekh and Jason
Simmons for technical assistanceSimmons for technical assistance
This research was conducted as part of USDA-This research was conducted as part of USDA-
ARS National Program 214: Agricultural andARS National Program 214: Agricultural and
Industrial By-ProductsIndustrial By-Products
Notes de l'éditeur
We sampled 2 weeks after application – 4 days before the peak, so the microbial population should be responding to the application in distinguishable ways At the time of sampling Nitrifiers oxidize ammonium to nitrate under aerobic conditions Denitrifying bacteria reduce nitrate to n2o or n2 gas under anaerobic conditions N2O produced from NH2OH (hydroxylamine) or from nitrite reduction Ammonia and methan-oxidizing organisme produce n20 during the oxidation of hydroxylamine to nitrite AOB also reduce NO2- to N2O and N2 under anoxic conditions – through denitrification Nitrate reduction can be performed with three different purposes: the utilization of nitrate as a nitrogen source for growth (nitrate assimilation), the generation of metabolic energy by using nitrate as a terminal electron acceptor (nitrate respiration), and the dissipation of excess reducing power for redox balancing (nitrate dissimilation). IN absense of oxygen nitrifiers (facultative anaerobes) may switch to respiring nitrate