Soil Fertility Management for Organic Farming Systems and Potential Disease Control Benefits

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Soil Fertility Management forOrganic Farming
Systems andPotential Disease Control Benefits
Dr. Sajeemas Mint Pasakdee, Soil
Scientist/Agronomist College of Agricultural
Sciences Tech., Fresno State
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Outline

• Definition--Organic Production
• Soil Fertility Management for Organic Crops
• Soil Organic Matter Plant Nutrition
• Nutrient and Water Management
• Organic Sources of Nutrients
• Potential Disease Control Benefits

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Organic Production

• USDA National Organic Program Standards 7 CFR
  PART 205
• A production system that is managed in accordance
  with the Act and regulations in this part to
  respond to site-specific conditions by
  integrating cultural, biological, and mechanical
  practices that foster cycling of resources,
  promote ecological balance, and conserve
  biodiversity.

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Soil Fertility Management

• Feed the soil to feed the plant
• Holistic approach
• Soil and plant interactions
• Soil properties
• Biology
• Chemistry
• Physics
• Soil Organic Matter (nutrient reservoir)
• Soil quality
• Soil health

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Soil Organic Matter

• Organic and Inorganic Nutrient Reservoirs
• Agricultural top soil 1-6
• In CA, 1-3 SOM

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Soil Fertility Management

• Nutrient and Irrigation Management
• Crop residue, Fertilizers
• Nutrient availability
• Biotic factors microbial activities, earthworm,
  etc.
• Abiotic factors water, soil temperature, O2
• Timing and Nutrient Availability
• Max. Nutrient Use Efficiency and Min. Nutrient
  Loss (N P)
• Soil Plant Tissue Testing

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Ranges of Total Soil C

• Locations Total Soil C ()
• (0-6 depth) Yr 1 Yr 3
• Santa Cruz 1.36 1.45 1.22 1.32
• (new org land)
• Five Points 6.78 8.36 7.32 8.72
• (gt5 yrs. org land)
• Compost applications at 5 tons/A annually
• S. Pasakdee (2006)

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Plant Nutrition

• Macronutrients C, H,
• O, N, P, K, S, Ca, Mg
• Micronutrients
• Trace elements
• B, Cl, Cu, Fe, Mn,
• Mo, and Zn

Plant Nutrition Manual by J. B. Jones (1998)
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Soil pH Nutrient Availability
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N Availability

• Mineralization
• Organic N to mineral N (NH4, NO3-)
• Nitrification (need O2)
• NH3 (Nitrosomonas) ?NO2- (Nitrobacter) ? NO3-
• Denitrification (depleted O2)
• NO3- ? NO2- ? NO ? N2O ? N2 gas
• Biological N Fixation
• Legume family (when N limit)
• N2 ? NH3 ? NH4

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Maximize Nutrient Uptake
Cool season vegetables (broccoli)
N (100-200 lbsN/A) Crop N Uptake
Side-dress N
Additive effects
Compost
Time (days)
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Interactions (Additive Effects)

• Compost only
• Compost mixed with Guano
• S. Pasakdee (2006)

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Improve Water Use Efficiency

• Crop evapotranspiration (ETc)EToKc
• Reference evapotranspiration (ETo)
• Crop coefficient (Kc)

CIMIS weather station
FAO, 1999
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Soil and Plant Tissue Testing

• Organic vs. Inorganic forms
• Organic N vs. NO3-, NH4
• Farm scale nutrient management plan (NMP)
• Input, Output, Nutrient Carry Over (residues)
• Soil test
• Plant tissue test
• Petiole nitrate
• Whole leaf total N (tomato-UCD,
  broccoli-Pasakdee, 2006)

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Leaf Total N vs. Yield Petiole Nitrate vs. Yield
UCSC farm
S. Pasakdee (2006)
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(Organic) Nutrient Budget

• Crop nutrient requirement
• Crop uptake, removal, and residue
• 10 to 15 of total N from manure will be
  available during the first year
• Recognize the nutrient accumulation over time
  from slow release nutrient sources
• Issue of P accumulation and water quality

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Organic Sources of Nutrients

• Natural-based fertilizers
• Compost
• Cover crops/Green manure/Catch crop
• Raw-Fresh-Aged manure
• Biosolids (composted sewage sludge)
• Urea (1st organic compound to be artificially
  synthesized from inorganic starting materials)

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USDA-NOP National List

• Approved materials by
• USDA-NOP
• Organic Materials Review Institute (OMRI)
• Washington State Dept. of Agri. (WSDA)
• International Federation of Organic Agriculture
  Movements (IFOAM)

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Which materials are approved?

• All aspects of agricultural practices, harvest,
  processing, and retails
• Fertilizers Soil Amendments
• Check up-to-date list before making decision
• Formulation and Manufacturing processes
• Not all organic materials are allowed
  (urea.GMOs).
• Some synthetic materials are allowed, e.g.,
• K2SO4 from mining is allowed.
• Humic Acid only natural ones not synthetic ones
• NaNO3 _at_20 of total N application (only for
  USDA but not for IFOAM label)

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Chilean Nitrate (NaNO3) Soil EC
2004
2002
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Manure vs. Compost
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Raw/Fresh/Aged Manure Application

• Food safety issues
• at least 120 days prior to the harvest of a
  product whose edible portion touches the soil or
  soil particle
• at least 90 days prior to the harvest of a
  product whose edible portion does not touch the
  soil or soil particles

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Cover Crops

• Crop rotation
• Biological control
• Green manure
• Biological N fixation
• Soil organic matter
• Catch crop (root depth)
• Minimize nutrient leaching

UC SAREP Cover Crop Database http//www.sarep.ucda
vis.edu/ccrop/
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Integrated Pest Management
Biological Control
Chemical Control
Cultural Control
Physical Control
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General IPM Guidelines for Weeds, Diseases, and
Insects

• Monitor populations
• Rotate crops
• Edge effect
• Alternate hosts
• Plant debris
• Barriers
• Mechanical traps

• Clean seeds
• Windbreaks
• Plant spacing
• Colors of crops
• Cover crops
• Trap crops

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Economic Thresholds
Maine Pest Management Dower, Dill, and Carter
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Potential Disease Control Benefits

• The American Phytopathological Society
• Compost (P.D. Miller, 2006)
• Raised-bed
• Alternative to fumigation
• Control of strawberry black root rot
• Compost (Abbasi et al., 2002)
• Conv. Org. tomato production system
• Reduction of fruit bacterial spot
• Reduction of anthracnose fruit spot

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Potential Disease Control Benefits

• Compost water extracts (Al-Dahmani et al., 2003)
• Reduction of bacterial spot (Xanthomonas
  vesicatoria) on tomato fruits and infected leaves
• Extracts performed better than direct soil
  application
• Notes Efficacy of the water extracts was not
  affected by oxygen conc. in the suspension during
  extraction, compost maturity, or sterilization by
  filtration or autoclaving.

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Potential Disease Control Benefits

• Poultry litter, Poultry compost, and Cover crops
  (Everts et al., 2006)
• Rotations potato, soybean, cucumber, grain
  sorghum, sorghum sudangrass
• Poultry litter and compost mixed with or without
  cover crops reduced root-lesion nematode
  incidence

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Potential Disease Control Benefits

• Hairy vetch (Zhou et al., 2006)
• Suppression of Fusarium wilt of watermelon
• Paper mill residuals (Stone et al., 2003)
• Compost and Non-composted PMR
• Suppressed cucumber damping-off, Pythium blight,
  foliar brown spot of snap bean

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Further Questions

• Dr. Sajeemas Mint Pasakdee
• spasakdee_at_csufresno.edu
• Tel. [phone]

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References

• Pasakdee, S. (2006) NITROGEN AND WATER MANAGEMENT
  IN ORGANIC VEGETABLE PRODUCTION IN CALIFORNIA
  IMPLICATIONS FOR SOIL PROPERTIES, PLANT NUTRIENT,
  AND FARM BUDGET ANALYSIS. PhD Dissertation. UC
  Santa Cruz.
• Images
• Earth worm http//www.edupic.net/animals.htm