1 / 14

Reading Assignment Chapter 7: Soil Aeration and Temperature

Reading Assignment Chapter 7: Soil Aeration and Temperature. Too much water for too long. Aeration relates to: Ventilation of soil with air (moving in and out of soil) The rate of gas exchange with atmosphere Proportion of pore spaces filled with air Composition of soil air

amela-simmons
Download Presentation

Reading Assignment Chapter 7: Soil Aeration and Temperature

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. Reading Assignment Chapter 7: Soil Aeration and Temperature Too much water for too long

  2. Aeration relates to: • Ventilation of soil with air (moving in and out of soil) • The rate of gas exchange with atmosphere • Proportion of pore spaces filled with air • Composition of soil air • Potential for oxidation and reduction (“redox”) within soil • Moisture status of soil • Temperature of soil • Survival of plants or vegetation

  3. Composition of Air & Soil Atmosphere

  4. GASEOUS EXCHANGE Mass flow (quicker, at shallow depth) Diffusion (concentration gradient, more important)

  5. Soil properties affecting aeration - Structure - Texture - Compaction - Drainage

  6.  Effect of poor aeration on plants and soil properties - As gas exchange is slowed, CO2 produced by organisms cannot escape fast enough and O2 required by organisms cannot enter fast enough - Other gases (H2S, methane, ethylene, etc.) produced by organisms can accumulate and maybe harmful to organisms and change soil chemical properties

  7. If soil contains < 15% O2, plant roots begin to suffer • < 10% O2, toxic substances may be produced

  8. Nutrients Bright Color.................................... Dull Color Fe+3 (oxidized) -------------------- Fe+2 (reduced) Mn+4 (oxidized) --------------------- Mn+2 (reduced) NO3- (oxidized) ---------------------- N2 (reduced) Insufficient oxygen Well Oxidized: sufficient Oxygen

  9.  How to improve Aeration? • Improve drainage • breakup impervious layers • improve aggregation (crumb structure) • prevent crusting

  10. REDOX POTENTIAL Oxidation reduction (REDOX) • Soil REDOX potential is a measure of a soil's ability to lose or gain electrons • Oxidation is the major mechanism of energy generation by organisms • Oxygen is required for respiration by plants and animals • The consumption of oxygen by biota is what reduces the REDOX potential in soil

  11. Oxidation from divalent to trivalent (loses an electron) (2+) (3+) 2 FeO + 2 H2O < = > 2 FeOOH + 2H+ + 2e- Fe(II) Fe(III)

More Related