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Compost tea: a brewable food web for disease control

Compost tea: a brewable food web for disease control. Martha Rosemeyer June 25, 2003 rosemeym@evergreen.edu. Outline. Background- what is compost tea? Organisms involved Does it work? How does it work? Future research Resources How to make it- David Bell. Photo: Seth Book.

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Compost tea: a brewable food web for disease control

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  1. Compost tea: a brewable food web for disease control Martha Rosemeyer June 25, 2003 rosemeym@evergreen.edu

  2. Outline • Background- what is compost tea? • Organisms involved • Does it work? • How does it work? • Future research • Resources • How to make it- David Bell Photo: Seth Book

  3. What is compost tea? • Water extract of compost that is brewed, ie fermented (Ingham, E. 2001) • Specifically the organisms are released from the compost and increase in number • Nutrients may be added to further increase organisms • Used for disease control, as well as a plant nutrient source

  4. Manure tea made as a nutrient source Plant extracts or herbal teas for disease control or plant health, for example biodynamic preparations Not to be confused with: Photos: Eliot Coleman’s European tour (Diver 2001)

  5. What does compost tea contain? • plant nutrients and humic acids • active bacteria (1 billion to 10 trillion cfu/ml) • active fungi • protozoa • nematodes • products of microbes that can have antibiotic properties Photo from: Compost Food Web slide show

  6. Why compost tea? Why now? • Increasing societal concern for health and environment and organic production • Lack of disease control mechanisms for organic farmers and gardeners • Restricting agrochemicals due to recognized toxicity, for example FQPA • Organic farmers need control methods that work within a holistic system

  7. Organic sales increasing at 20+% per year Worldwatch Institute. 2000. Why Poison Ourselves.

  8. Used extensively due to perceived benefits • Homeowners • Nurseries • Organic crop growers • Golf courses • Organic landscape management • municipal parks and recreation dept BUT LITTLE RESEARCH HAS BEEN DONE Without tea With Tea Ingham 2001

  9. Background • Since 1920’s compost water used to soak seeds for nutrients, prevent disease • Two main approaches • compost extracts = watery fermented compost extract= steepages =non-aerated compost tea (Scheuerell and Mahaffee 2002) • fermented but not aerated, stirred occasionally • lower costs, lower energy • much research • disease control has been documented

  10. aerated compost tea • fermented, aerated • higher costs, energy • little research, some disease control reports Diver 2001

  11. Benefits of compost tea • Nutrient application, lesser • Disease control • Foliar disease • Root disease • Inoculation of functioning soil food web

  12. How to make non-aerobic compost tea • Mix ratio of compost to water-1:4-1:10 compost to water in an open container, stir occasionally • At least 3 days at 15-25°C (50-70 °F)

  13. How to make Aerobic Compost Tea • Choose compost- well aged • plant based or worm compost • In water (remove chlorine from water) • Ratio 1 compost:10 water to 1:50 • Add nutrients (optional) like molasses, humic acids, kelp • Aerate and mix solution for 12 - 24 - 48 hours

  14. Commercial aerobic compost tea brewers • Soil Soup: www.soilsoup.com • Microb Brewer: www.microbbrewer.com • Growing Solutions: www.growingsolutions.com • Earth Tea Brewer: www.composttea.com • Xtractor: compara.nl/compost_tea_systems.

  15. Soil Soup www.soilsoup.com

  16. Microb Brewerwww. microbbrewer.com

  17. Growing Solutions www.growingsolutions.com • bubbling aeration

  18. What happens in the compost tea while brewing? ? ?

  19. TESC Student expts: Scott Chichester and Seth Book • Changes in compost tea • during brewing • Preventing damping off • of marjoram Photos: Seth Book

  20. ppm Dissolved Oxygen >5.5 ppm 48 hrs 24 hrs ppm 20 hrs From: Book and Chichester

  21. pH > 7.2 °C From: Book and Chichester

  22. Food web concept ”Everything eats, everything excretes, and everything is food for something" • Elaine Ingham, 2001 A great resource: SWCS/NRCS, Soil Biology Primer

  23. A functioning food web is desirable in a compost tea From: Soil Biology Primer

  24. Most bacteria (99%) cannot be cultured • Direct counts and genetic diversity assessment • Activity of bacteria important • Nutrients can help to “wake up” to active state A ton of microscopic bacteria may be active in each acre of soil. Bacteria dot the surface of strands of fungal hyphae. From: Soil Biology Primer

  25. Fungus beginning to decompose leaf veins in grass clippings. Soil Microbiology and Biochemistry Slide Set. 1976. J.P. Martin, et al.,eds. SSSA, Madison WI. From: Soil Biology Primer

  26. bacteria Protozoa: Flagellates have one or two flagella which they use to propel or pull their way through soil. A flagellum can be seen extending from the protozoan on the left. The tiny specks are bacteria. Credit: Elaine R. Ingham, Oregon State University From: Soil Biology Primer

  27. Protozoa:Ciliates are the largest of the protozoa and the least numerous. They consume up to ten thousand bacteria per day, and release plant available nitrogen. Ciliates use the fine cilia along their bodies like oars to move rapidly through soil Credit: Elaine R. Ingham, Oregon State University, Corvallis From: Soil Biology Primer

  28. cysts Interaction Vampyrellidae attack fungus “take all” of wheat From: Soil Biology Primer

  29. Most nematodes in the soil are not plant parasites. Beneficial nematodes help control disease and cycle nutrients. Credit: Elaine R. Ingham, Oregon State University, Corvallis From: Soil Biology Primer

  30. Interactions: Nematode trapping fungi From: Soil Biology Primer

  31. Total population of active microbes • Bacteria minimum 107-1010 (Scheurell and Mahaffee) • But may not be associated with disease control, if appropriate agent not present!

  32. Do we know what the diversity or quantity of microbes means with respect to disease? • Not entirely • Most soil organisms are unknown! • Does microbial diversity increase microbial function? • If we are mainly interested in disease prevention then do we know what mechanism and whether that organism is involved? • In general more diversity means better change that have the appropriate organism

  33. Does it work? • NCT- Good evidence under certain circumstances • Much research with • grey mold (Botrytis cineraria) Downy mildew of grape (Plasmopara viticola)

  34. Evidence of NCT disease suppression Diver, 1998

  35. Is ACT better than NCT? • Both ferment well-characterized compost in water for a period of time, with or without nutrients • Few studies have actually compared the two • NCT has been suggested to cause plant problems and potentially an environment for human pathogen growth (Ingham) • According to Scheuerell and Mahaffee, there is no evidence that phytotoxic symptoms

  36. Apple scab control using NCT but not ACT manure-based spent mushroom compost (Cronin et al. 1996) • ACT (7 d) vs. NCT (7d) • In vitro effect on germination of conidia of Venturia inaequalis, pathogen of apple scab • NCT reduced conidia germination, not ACT unless let sit for another 7 days Apple scab on leaf and fruit

  37. Powdery mildew of rose(Scheurell and Mahaffee 2000) • Three sources of compost • ACT commercial preparation vs. 7-day NCT • All equal results on powdery mildew of rose (Sphaerotheca pannosa) within source of compost • Authors concluded that source of compost more important than ACT or NCT

  38. Tests for Disease control of ACT

  39. Disease control with ACTGranatstein 1999 • ACT had effects on yield and disease control • No effect on early blight of tomato • Lettuce drop incidence decrease in summer not spring • Post harvest rot of blueberries significantly reduced, but reduced yields • Spinach yield decreased, but broccoli spring and summer increased • No general pattern

  40. Disease control with ACTPresidio golf greens Decreased No effect Microdochium Anthracnose Conforti et al. 2002

  41. Bacterial vs. fungal dominated teas can be determined by added nutrients (Ingham 2001) • Bacterial- use simple sugars to fulvic acids • Fungal- use humic acids Have been difficult for some to produce fungal dominated teas (Scheuerell and Mahaffee 2002) • Reports on reduction of suppression due to nutrient competition? • Useful to know nutrients that support antagonists

  42. How might compost teas work?Mechanisms from NCT • Prevention of pathogen colonization • due to competition of space or nutrients • direct destruction of pathogen • Antibiosis • Release of antimicrobial compounds • Induced resistance

  43. Colonization of phylloplane If 70% of leaf covered by organisms reduction of disease (Ingham) • 60-70% active bacteria and 2-5% active fungi • Various authors Pseudomonads, aerobic Bacillus, aerobic spore forming bacteria with reduction in powdery mildew of grape

  44. Predation NCT: Fusarium spore rupture • Root drench for Fusarium diseases of pepper and cucumber • Direct destruction on disease-causing spores Ascospores of Fusarium solani

  45. Antibiosis: what organisms and metabolites may be involved? • Bacteria- Bacillus, Pseudomonas, Serrantia • Yeast- Sporobolomyces, Cryptococcus • Fungi- Trichoderma, Gliocladium and Penicillium Chemicals involved - phenols, amino acids, low molecular weight non-protein (sometimes produced by fermentation and other times already within compost)

  46. NCT induced resistance to plant pathogens • Powdery mildew of cucurbits (Sphaerotheca fuliginea) • NCT changed host response to pathogen • papillae (bumps) • necrotic reaction • leaf toughens (lignification)

  47. Standards for compost tea So far only one proposed minimum standards (Ingham 2001) • oxygen concentration remain above 5.5 ppm or 60% DO [but there is disease suppression in NCT] • in vitro pathogen inhibition [but question as to whether this reflects field conditions]

  48. Minimum standards for compost tea/mL (Ingham 2001) • 10-150 g active bacteria,150-300 g total bacteria • 2-10 g active fungi, 5-20 total fungi • 1000 flagellated protozoa • 1000 amoeba-type protozoa • 20-50 ciliates protozoa • 2-10 beneficial nematodes (soil drench)

  49. How to test? • Send compost tea to Soil Food Web (direct counts) • BBC Labs, Vicki Bess • Need to correlate counts to field performance

  50. Potential to support human pathogens • Appears that despite popular conception, ACT can support human pathogens if fermented with sugars (2 papers) • If no sugars, including molasses, are used then neither ACT and NCT appear to be able to maintain human enteric pathogens (Escherichia, Salmonella, Shigella, Yersinia) even if contain low levels of pathogens • If use worm compost as source appears that can avoid pathogens • Needs more research

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