1 / 20

Soil resistance and resilience to compaction as affected by the clay-organic carbon relation

Emmanuel Arthur Per Moldrup Per Schj ønning Lis W. de Jonge. Soil resistance and resilience to compaction as affected by the clay-organic carbon relation. ASA , CSSA, and SSSA  International Annual Meetings Oct 16-19, 2011 San Antonio, TX. Introduction.

teague
Download Presentation

Soil resistance and resilience to compaction as affected by the clay-organic carbon relation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Emmanuel Arthur Per Moldrup Per Schjønning Lis W. de Jonge Soil resistance and resilience to compaction as affected by the clay-organic carbon relation ASA, CSSA, and SSSA International Annual Meetings Oct 16-19, 2011San Antonio, TX

  2. Introduction • Anthropogenic stresses imposed on soils challenge their ability to function • Soil stability is characterized by its resistance and resilience to imposed stress • Compaction by agricultural machinery increases bulk density and reduces pore functions ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  3. Introduction • Soils resistance and resilience to compaction is driven by several factors (water content, texture, clay type, organic matter etc.) Hypothesis • The main driver governing resilience in soils is the level of clay saturation by organic carbon ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  4. Introduction Objective • Assess the role of clay saturation by organic carbon in soil resilience to compaction using three functional indicators ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  5. Methodology • Functional indicators: • Void ratio, e • Air permeability, ka • Air filled porosity, ε ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  6. Methodology • Soils – 3 sandy loams: ~17 % clay Different long term management = different organic carbon contents: MFC = Mixed forage cropping MCC = Mixed cash cropping CCC = Cereal cash cropping 10g clay ≈ 1g OC (Dexter et al., 2008) 1:10 line ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  7. Methodology • Compaction test Freeze-thaw cycles [FT] -10°C & -100 hPa Compaction (200kPa) @2mm/min 100 cm3 7 days -100 hPa drained to -100 hPa (Void ratio, e; air permeability, ka Air filled porosity, ε) Rebound recovery [RR] (ka, ε, e) ka, ε, e Wet-dry cycles [WD] saturation & 40°C Resistance (RST) ka, ε, e ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  8. Methodology • Quantification of resistance and resilience • Compression index, Cc, from Gompertzmodel σ = applied stress e = void ratio a, b, c = model parameters Low Cc = high resistance to compaction ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  9. Methodology • Quantification of resistance and resilience • Compression index, Cc, from Gompertzmodel • Absolute values (e, ka, ε) • Indexed values: Resistance [RST] = Original value – Value after compaction Original value Resilience [PR] = Original value – Recovery value Original value Range : 0 – 1 0 = maximum resistance/resilience 1 = no resistance/resilience ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  10. Results • Functional indicators prior to compaction (-100hPa) ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  11. Results • Functional indicators prior to compaction (-100hPa) ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  12. Results • Compaction resistance (Cc) ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  13. Results • Compaction resistance (Cc) • Higher clay saturation = higher compression resistance • Increasing initial void ratio has relatively less impact on Cc for MFC ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  14. Results • Resistance (RST) and resilience (PR) • Air permeability Absolute values Indexed values ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  15. Results • Resistance (RST) and resilience (PR) • Void ratio Absolute values Indexed values ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  16. Results • Resistance (RST) and resilience (PR) • Air-filled porosity Absolute values Indexed values ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  17. Results • Relation between resistance and resilience (void ratio) ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  18. Conclusions • For differently managed soils, the clay-organic carbon relation governs structural stability • Increased saturation of clay by organic matter: • increased compaction resistance usingεand e as indicators • reduced the effect of initial void ratio on compression resistance • Increased soil resilience after natural recovery, wet-dry and freeze-thaw cycles ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  19. Acknowledgements • Project Soil Infrastructure, Interfaces, and Translocation Processes in Inner Space (Soil-it-is) • Funding Danish Research Council for Technology and Production Sciences • STAiR ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

  20. ASA, CSSA, and SSSA International Annual Meetings. Oct 16-19. San Antonio, TX

More Related