Towards assessing climate sensitivity of microbial processes and its effect on greenhouse gas fluxes in subtropical pastures

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Information about Towards assessing climate sensitivity of microbial processes and its...

Published on December 23, 2016

Author: NIFA_IBCE

Source: slideshare.net

1. Stefan Gerber, Saroop Sandhu, Dipti Rai, Kanika Inglett, Patrick Inglett, Ryan Penton, and Maria Silveira sgerber@ufl.edu Towards assessing climate sensitivity of microbial processes and its effect on greenhouse gas fluxes in subtropical pastures

2. Site location: USDA-LTAR - UF IFAS Range and Cattle Research and Education Center, Ona Florida

3. • Characterize the soil microbial community across different management practices and measure the corresponding greenhouse gas fluxes. • Determine the adaptation and acclimation of the soil microbial community climate change. • Improve a soil greenhouse gas emission model to predict greenhouse gas emissions under global change scenarios Project start was August, 2016 Project Objectives

4. Consistently managed sites

5. Native Rangeland Improved Pasture

6. Preliminary Laboratory Analyses

7. Initial Soil Characterization

8. • Management has no impact on bulk density of soil. However, bulk density is significantly different for soil horizons. • Bh horizon has lower bulk density compared to E2 probably be due to more organic carbon present. • Soil pH is higher in managed grassland might be due to the addition of manure from cattle grazing. • Also, soil pH increases with depth. Preliminary results

9. • Management has no impact on moisture content of soil. However, moisture content is significantly different for soil horizons. • Managed grassland has higher aerobic respiration rate which may be due to extra nitrogen source available by manure and chemical fertilizer additions. Preliminary results

10. • Enzymes –β-glucosidase –Cellobiose Dehydrogenase –N-Acetyl-β-D Glucosaminidase –Leucyl aminopeptidase • Microbial biomass carbon and nitrogen • Total carbon and nitrogen • Anaerobic respiration • Isotope analysis • Carbon fractions Analyses in progress

11. Future steps Adressing Microbial Response • 3 Key responses - Kinetic response (e.g. Vmax) - fast - molecular analysis to address functional (gene expressions) slower - community response – slowest • Incorporation of key responses into a new microbial-based decomposition and greenhouse gas production module in DNDC

12. Conceptual/Numerical Model Functional and community response Kinetic Response Sihi et al., 2016, Biogeoscience

13. Expect different climate response Sihi et al., 2016

14. Laboratory experiment and field data – Assessing of CO2, N2O fluxes In the field: take advantage of seasonal and interannual cycle

15. We’ll go out some more!

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