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ROOTSThe hidden half of agriculture
How many of you regularly   look at crop roots ?                   John McGillicuddy                   IA crop scout
Bill Darrington (Persia, IA)One of several readings     for this week
Read the attached article and submit answers using WO before the start of classnext Wednesday.1)Describe several factors c...
Ken Ferrie – Farm Journal
All you need to do to grow healthy roots       is use rootworm resistant genetics… right??When rootworm pressure is high, ...
Rootworm resistant genetics are not a silver bullet !                                     Severe damage by corn           ...
We have witnessed the historically low densities of  European corn borers across Illinois and some nearbystates that are n...
U of I Corn Borer survey results
The seed roots stop growing shortly after the coleoptile emerges from the soil surface. The nodal root system   becomes vi...
16 weeks  8  47 feet deep !!
1926
Sub-soil waterand nutrients                 Brady and Weil (2002)
Sidewall compaction        ?
Waiting for drier soilis the most important strategySidewall compaction             ?
Tillage systems   affect root  architecture            Adapted from Hunt et al. (1986)
Long term no-till                                  (w/ healthy soil biology)             Intensive tillage                ...
Which solutionwould you use ?
WIU Allison Organic Research Farm – September 2007
January
February
Early MayWarmer and drier than soilwith other cover crops and almost no weed growth
Visual evidence of biodrillingCanola rootRapeseed root
The experiment was planted to     corn on May 29 2008     Corn following radishestablished well, had the lowest   in-row w...
Chemical toxicitiescan inhibit root growth             Aluminum              toxicity                          Aluminum   ...
Galled root system of tomato infected with root-knot nematode, Meloidogyne sp., compared with non-                infected...
Root knot juvenile penetrating a tomato root
You won’t know what is happeningunderground unless you take a look…
All you need          is a shop-vac           and a hose!Its just like going to the dentist!
Roots have many functions !
Absorptive network for limiting soil resourcesof water and nutrientsMechanical structures that support plants,strengthen...
Carbon pumps that feed soil organisms and      contribute to soil organic matter             Storage organsChemical fac...
Macro-anatomy of roots
Micro-anatomy of rootshttp://www.sparknotes.com/biology/plants/plantstructures/section2.rhtml
What is the function of the root cap?
The cell wall of the endodermis (pink inner strip of cells) is waterproofed by theCasparian strip, which forces water to e...
Apoplast vs. symplastThe movement of fluids from the root hairs to the xylemcan occur through one of two conductive pathwa...
http://www.mie.utoronto.ca/labs/lcdlab/biopic/fig/35.03.jpg
Water moves upwardthrough plantswhenever there is aprogressively morenegative gradient ofwater potential alongthe soil-pla...
H20A continuous                 Solar energychain of water                              drives the molecules is           ...
Understanding nutrient uptake                                                      H20              Root exudatesN, S, P  ...
Nutrient uptake is an active and selective process  outside cell                                               inside cell
Rhizosphere Roots normally occupy < 1% of topsoil volumeThe rhizophere isnormally < 10 % of soilvolume                    ...
Navigating the rhizosphere                                                          End of the                           R...
Both strategies are important !Feed the soil vs. Feed the crop??? Unhealthy roots use nutrients inefficiently…  Healthy ro...
How do you know if a crop has healthy roots?                                     extend into the   white color            ...
Healthycowpeanodule with a  pinkinterior
Legume  nodules  come inmany shapes and sizes
Lots of complicated biochemistry – very intensively studied!!Legume  love affair                                          ...
Examples of rhizobia innoculant
Inoculation groups for commonly grown legumes   Alfalfa Group                        Alfalfa       (Rhizobium meliloti)   ...
Mycorrhizal associations                      Ectomycorrhizae                                         AM endomycorrhizaeAr...
Ectomycorrhizal roots
Close up of ecto-mycorrhiza
Mycorrhizal Networks: Connecting    plants intra- and interspecifically                                 •Many plants are  ...
Increase nutrient (P) uptake          suppress pathogens Mediate plant competition           Improve soil structure       ...
Roots
Roots
Roots
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Roots

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2nd lecture presentation of the semester for my Soil Fertility class

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Roots

  1. 1. ROOTSThe hidden half of agriculture
  2. 2. How many of you regularly look at crop roots ? John McGillicuddy IA crop scout
  3. 3. Bill Darrington (Persia, IA)One of several readings for this week
  4. 4. Read the attached article and submit answers using WO before the start of classnext Wednesday.1)Describe several factors contributing to deep root growth on Bill Darringtonsfarm.2) The article refers to Ray Rawson as the guru of "vertical farming"... what is"vertical farming" and what did Bill Darrington learn from Ray Rawson about soilaeration?3) Why does Bill Darrington dig so many soil pits and what does he look for?4) What is Bill Darringtons perspective on anhydrous ammonia? Do you agreewith this perspective?5) Have you ever looked at roots in a soil pit? If so, describe something youobserved. If not, when do you think you will have an opportunity to look at someroots? What do you think you will see?
  5. 5. Ken Ferrie – Farm Journal
  6. 6. All you need to do to grow healthy roots is use rootworm resistant genetics… right??When rootworm pressure is high, rootworm resistant genetics normally result in much healthier roots
  7. 7. Rootworm resistant genetics are not a silver bullet ! Severe damage by corn rootworm larvae to roots of a biotech corn rootworm hybrid http://www.ipm.iastate.edu/ipm/icm/2006/11-13/btcorn.html
  8. 8. We have witnessed the historically low densities of European corn borers across Illinois and some nearbystates that are now believed to be linked to the widespread adoption of Bt corn hybrids. Will we see a similar phenomenon unfold with western corn rootworms? I suspect we might be headed down this road. Will westerncorn rootworms adapt as they have repeatedly done so in the past? If we dont integrate management tactics, we could have the answer sooner than we would like.
  9. 9. U of I Corn Borer survey results
  10. 10. The seed roots stop growing shortly after the coleoptile emerges from the soil surface. The nodal root system becomes visible at ~ V1. The nodal root system becomes the dominant system by V6.
  11. 11. 16 weeks 8 47 feet deep !!
  12. 12. 1926
  13. 13. Sub-soil waterand nutrients Brady and Weil (2002)
  14. 14. Sidewall compaction ?
  15. 15. Waiting for drier soilis the most important strategySidewall compaction ?
  16. 16. Tillage systems affect root architecture Adapted from Hunt et al. (1986)
  17. 17. Long term no-till (w/ healthy soil biology) Intensive tillage Network Plow pan of bioporesOntario Ministry of Ag and Food
  18. 18. Which solutionwould you use ?
  19. 19. WIU Allison Organic Research Farm – September 2007
  20. 20. January
  21. 21. February
  22. 22. Early MayWarmer and drier than soilwith other cover crops and almost no weed growth
  23. 23. Visual evidence of biodrillingCanola rootRapeseed root
  24. 24. The experiment was planted to corn on May 29 2008 Corn following radishestablished well, had the lowest in-row weed pressure and yielded about 10 bu more.
  25. 25. Chemical toxicitiescan inhibit root growth Aluminum toxicity Aluminum toxicity
  26. 26. Galled root system of tomato infected with root-knot nematode, Meloidogyne sp., compared with non- infected root system Root pathogens can inhibit root growth http://www.agnr.umd.edu/users/nrsl/entm/nematology/images/eis143.jpg
  27. 27. Root knot juvenile penetrating a tomato root
  28. 28. You won’t know what is happeningunderground unless you take a look…
  29. 29. All you need is a shop-vac and a hose!Its just like going to the dentist!
  30. 30. Roots have many functions !
  31. 31. Absorptive network for limiting soil resourcesof water and nutrientsMechanical structures that support plants,strengthen soil, construct channels, breakrocks, etc.Hydraulic conduits that redistribute soil waterand nutrientsHabitats for mycorrhizal fungi, rhizosphereand rhizoplane organisms
  32. 32. Carbon pumps that feed soil organisms and contribute to soil organic matter Storage organsChemical factories that may change soil pH, poison competitors, filter out toxins, concentrate rare elements, etc.A sensor network that helps regulate plant growth
  33. 33. Macro-anatomy of roots
  34. 34. Micro-anatomy of rootshttp://www.sparknotes.com/biology/plants/plantstructures/section2.rhtml
  35. 35. What is the function of the root cap?
  36. 36. The cell wall of the endodermis (pink inner strip of cells) is waterproofed by theCasparian strip, which forces water to enter the symplast before it can enter theroot xylem phloem root hair xylemepidermis endodermis cortex
  37. 37. Apoplast vs. symplastThe movement of fluids from the root hairs to the xylemcan occur through one of two conductive pathways–the apoplast and the symplast.The apoplast route consists of inter-cellular spaceswithin the root cortex along which water and solutescan diffuse.The symplast route consists of channels through cellsalong which water and solutes are actively transported.
  38. 38. http://www.mie.utoronto.ca/labs/lcdlab/biopic/fig/35.03.jpg
  39. 39. Water moves upwardthrough plantswhenever there is aprogressively morenegative gradient ofwater potential alongthe soil-plant-atmospherecontinuum
  40. 40. H20A continuous Solar energychain of water drives the molecules is process pulled up through the Plants provide plant the conduit H20 H20 H20
  41. 41. Understanding nutrient uptake H20 Root exudatesN, S, P activate soil microbes Transpirational Root growth stream H 20 Diffusion
  42. 42. Nutrient uptake is an active and selective process outside cell inside cell
  43. 43. Rhizosphere Roots normally occupy < 1% of topsoil volumeThe rhizophere isnormally < 10 % of soilvolume Zone of root influence
  44. 44. Navigating the rhizosphere End of the Rhizoplane rhizosphere Endo- Rhizosphere Ecto-RhizosphereMicrobial activity > 90% < 10% of soil volume of soil volume A few millimeters (Lavelle and Spain, 2001)
  45. 45. Both strategies are important !Feed the soil vs. Feed the crop??? Unhealthy roots use nutrients inefficiently… Healthy roots need available nutrients ! Acute root disease Chronic root malfunction
  46. 46. How do you know if a crop has healthy roots? extend into the white color B horizonproliferate in all minimal directions evidence of deformities
  47. 47. Healthycowpeanodule with a pinkinterior
  48. 48. Legume nodules come inmany shapes and sizes
  49. 49. Lots of complicated biochemistry – very intensively studied!!Legume love affair Sarrantonio
  50. 50. Examples of rhizobia innoculant
  51. 51. Inoculation groups for commonly grown legumes Alfalfa Group Alfalfa (Rhizobium meliloti) Black medic Bur clover Button clover White sweetclover Yellow sweetclover Clover Group Alsike clover (Rhizobium trifolii) Arrowleaf clover* Ball clover Berseem clover Crimson clover Hop clover Persian clover Red clover Rose clover* Subterranean clover* White clover Cowpea Group AlycecloverSoybean has its own inoculation group!! (Bradyrhizobium japonicum spp.) Cowpea Kudzu Peanut
  52. 52. Mycorrhizal associations Ectomycorrhizae AM endomycorrhizaeArbutoidmycorrhizae Ericoid endomycorrhizae Orchid endomycorrhizae Lavelle and Spain (2001)
  53. 53. Ectomycorrhizal roots
  54. 54. Close up of ecto-mycorrhiza
  55. 55. Mycorrhizal Networks: Connecting plants intra- and interspecifically •Many plants are connected underground by mycorrhizal hyphal interconnections. •Mycorrhizal (AM) fungi are not host specific.Illustration by Mark Brundrett
  56. 56. Increase nutrient (P) uptake suppress pathogens Mediate plant competition Improve soil structure Glomalin Superglue of the soil ??

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