Soil Biological Responses to Biochar Amendments Janice E. Thies Crop and Soil Sciences Cornell University Midwest Biochar Conference August 2014
Proposed benefits of energy and biochar coproduction from biomass 2
How is the soil microbial community affected by the micro-environment on and around biochar? J. Grossman Live (green) Dead (red)
Variation among feedstocks is high and measurements change over time Characterization is critical Photo by M. Yamato
Characterizing biochar for soil use Downie, Joseph and Lehmann, 2009 Feedstock - physical and chemical properties Process Conditions - time temperature, activation Post Processing - ageing, oxidation, added nutrients Biochar physical and chemical properties Bulk density, surface area, porosity and pore size distribution CEC, ph, electrical conductivity C/H/O/N/P/S, Ash %, other elements Composition and % volatile organics Surface functional groups Distribution of mineral phases (surface and bulk) Solubility of organics and minerals 5
Biochars are not created equal
Biochars are not created equal
Soil quality and processes Root proliferation, Movement of soil organisms Aeration Water retention Water infiltration and transmission; erosion prevention Physical Biological Pest suppression N mineralization OM decomposition Habitat protection Chemical Nutrient retention and release N P, K, Ca, Mg, etc. micronutrients ph Energy (C) storage Salinity/Toxicity prevention
Model of potential interactions Microbes Inorganic nutrients Exoenzymes Soil organic matter
Soil microbial response metrics Abundance Microbial biomass PLFA qpcr Culturing Activity CO 2 evolution Other GHGs N cycling Soil enzymes Diversity PLFA Culturing T-RFLP Sequencing Constraints Adsorption
Biochar Amendment Soil Mixed samples Biochar particles Microbial respiration DNA extraction Exoenzyme activity Exoenzyme Localization Microbial biomass Exoenzyme dynamics Fungi 18S rrna PCR Bacterial 16S rrna PCR Microbial activity Microbial abundance T-RFLP Fingerprinting Microbial community composition
Adsorption of DOC on biochar and soil 54.0% 32.4% 12
Microbial Biomass C
Microbial abundance
qpcr of N cycling genes
CO2 evolution 16
Bulk soil Soil respiration Rhizosphere soil 17
Metabolic quotient Increased C use efficiency 18
Soil respiration in bulk soil at 5 years Cumulative CO 2 6 week incubation Accumulated CO2 (mg) 180 160 140 120 100 80 60 40 20 0 Series1 Series2 Series3 Series4 Series5 Weeks
Bacterial diversity 24 months Bulk [12 & 30 t ha -1 ] Rhizosphere [0 and 1 t ha -1 ] 20
2007 vs. 2008
2007-2008 Microbial abundance (culturable and total microbial biomass) was higher in biochar-amended soils. Community composition of Bacteria, Archaea and fungi varied in relation presence or absence of biochar. Presence of roots and seasonal changes are also dominant drivers.
Fig. 4. AMMI analysis of bacterial community composition generated by T-RFLP after filtering noise and aligning T-RFs (Peaks) Rhizosphere 16S rdna (15.46%) Replicates Char (tons/ha) E1, E2, E3: 0 E4, E5, E6: 1 E7, E8, E9: 3 E10,E11,E12: 12 E13, E14: 30 E15 (27R 30 char): Data NA due to poor quality of T-RFLP. (19.18%)
Fig. 1. AMMI analysis of bacterial community composition generated by T-RFLP after filtering noise and aligning T-RFs (Peaks) (17.09%) Bulk soils 16S rrna Replicates Char (tons/ha) E1, E2: 0 E3, E4, E5, 1 E6, E7, E8: 3 E9, E10,E11: 12 E12, E13, E14: 30 8B (0 char): Data Not Available (NA) due to poor quality of T-RFLP. (27.30%)
Bulk vs Rhizosphere soil (20.19%) Bulk Rhizosphere Samples Char (t/ha) E1, E6: 0 E2, E7: 1 E3, E8: 3 E4, E9: 12 E5, E10: 30 (22.67%) AMMI analysis of bacterial community composition generated by T-RFLP (16S rrna genes)
Enzyme activities
Enzyme linked fluorescence Phosphatase activity β-d-glucuronidase activity 27
Enzyme linked fluorescence Biochar amended 3 hr 4 hr Unamended 4 hr Phosphatase β D glucuronidase Phosphatase 28
Summary of GeoChip operations A. GeoChip development Sequence retrieval B. Target preparation Environmental sampling DNA extraction & purification C. GeoChip analysis Array scanning & image analysis Data preprocessing Probe design and verification DNA amplification Target labeling Data normalization Array construction Array hybridization Statistical analysis He et al. (2011), FESEC.
GeoChip 4.0 The most comprehensive functional gene array Functional process No. of gene categories No. sequences retrieved No. of probes designed No. CDS covered Antibiotic resistance 11 15754 3349 5547 Bacterial phage 40 3644 1100 2083 Carbon degradation 33 21529 9033 13667 Carbon fixation 5 5252 1762 3398 Methane metabolism 3 9718 507 1677 Nitrogen cycling 17 47988 7552 17550 Phosphorus utilization 3 3783 1378 2261 Stress 45 75305 21574 41033 Sulfur cycling 6 8078 3254 4461 Metal remediation 44 25277 9478 17575 Contaminant degradation 184 44220 17919 30361 Energy process 4 1762 862 1131 Virulence 13 16762 3732 7444 Others ( gyrb, bchy) 2 7830 2492 4226 Total 410 286,902 83,992 152,414
All samples Bulk and Rhizosphere Soil Rhizosphere soil Bulk soil
All Samples Biochar Applied 0, 3, 12,30 t ha -1
N cycling processes
Biological nitrogen fixation
Biological nitrogen fixation David Guerena
Biological nitrogen fixation David Guerena David Guerena
(1) Chemotaxis (2,3,4) Flavonoids (5) Aliphatic acids (6) Cytokinins (7) QS and attractants (8) Fatty acids (9) Proteins (10) Other secretions of unknown function
Sorption of signaling molecules blocks bioreactions Masiello et al
Reduced soil-borne disease Charcoal compost Control Yang et al., 2003 40
Future directions Develop a mechanistic understanding of Feedstock x pyrolysis conditions interactions and resultant effects on microbial responses over time in the field. How the unique properties of biochar, soil type and climate interact to influence the soil microbial community preserve soil fertility.
Acknowledgements Hongyan Jin Jin Su Kai Xue David Güereña Julie Grossman Johannes Lehmann