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.

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)

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

8. InjectionInjection
Surface ApplicationSurface Application
AerationAeration
Methods ofMethods of
Swine ManureSwine Manure
ApplicationApplication

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

16. NitrifiersNitrifiers

18. DenitrifiersDenitrifiers
Nitrate Reducers;Nitrate Reducers; narGnarG
Nitrite Reducers;Nitrite Reducers; nirKnirK
Nitrous Oxide Reducers;Nitrous Oxide Reducers; nosZnosZ

19. Nitrate Reducers;Nitrate Reducers; narGnarG

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