George Abawi, Dan Brainard, Dan Clune, Kathryn Duhamel, Beth Gugino, Omololu John Idowu, Hilary Mayt

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George Abawi, Dan Brainard, Dan Clune, Kathryn
Duhamel, Beth Gugino, Omololu (John) Idowu,
Hilary Mayton, Bianca Moebius, Bob Schindelbeck,
Janice Thies, Harold van Es, and David
WolfeDepartments of Crop and Soil Sciences,
Horticulture, and Plant Pathology
Soil Health Assessment on New York Vegetable
Farms
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Aspects of Soil Health

• Inherent soil quality
• Results from natural soil forming processes and
  factors
• Dynamic soil quality
• Changes due to human use and management

interaction
(Pierce and Larson, 1993)
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Soil Health and Processes

• Root proliferation, organismal locomotion
• Aeration
• Water retention
• Water infiltration and transmission erosion
  prevention

• Nutrient retention and release
• N
• P, K, Ca, Mg, etc.
• micronutrients
• pH
• Energy (C) storage
• Toxicity prevention

Chemical
Physical
Biological

• Pest suppression
• N mineralization
• OM decomposition
• Habitat protection

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How Healthy is a Soil?

• How to measure?
• 2. Which are meaningful indicators?
• 3. What are appropriate sampling protocols?

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Soil Health Indicators

• OM
• Active C, N in OM
• Cation exchange capacity
• N, P, K
• Micronutrients
• Toxins, pollutants
• Glomalin

• Bulk density
• Penetration resistance
• Aggregate stability
• Water infiltration rate
• Water holding capacity
• Pore size distribution

Chemical
Physical
Biological

• Soil disease suppressive capacity
• Beneficial and pathogenic nematodes, other
  pathogens
• N mineralization rate (PMN)

• Decomposition rate
• microbial biomass
• Respiration rate
• Earthworm counts
• Genetic diversity

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Soil health testing procedures must be

• Rapid
• Inexpensive
• Scientifically meaningful
• Agronomically useful

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Our Approach Research Farm Experiments Provide
scientific basis from controlled trials to
establish useful indicators Commercial Farm
Samples Provide real-world perspective under
range of conditions

700 SAMPLES WERE ANALYZED FOR MULTIPLE POTENTIAL
SOIL HEALTH INDICATORS
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Criteria for Selecting Soil Health Indicators

• Sensitivity to management
• Functional relevance
• Consistency and reproducibility
• Ease (cost) of sampling
• Cost of analysis
• Opportunity to be estimated by statistical
  correlation

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Field Measurements
PENETRABILITY
INFILTRABILITY
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LAB MEASUREMENTS
DISTURBED SAMPLE
UNDISTURBED SAMPLE
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Aggregates Creating and protecting these crumbs
keeps the soil open to rain and to air exchange.
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Methodology Aggregate Stability disturbed
samples
WSAlg 2mm sieve 2-8mm aggregates
WSAsm 0.25mm sieve 0.25-2mm aggregates
Aggregates before stability test
1.25cm rainfall in 5 min, providing Energy of
0.142mJ/drop, total of 2.5J/sieve
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Results and Interpretation of Aggregate Stability
Test
of Soil crumbs stable to 1.25cm
rain/5mins Organic management 70 -
high Conventional management 20 - low
2mm sieves
Aggregates after stability test
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Soil Pores

• Porosity is important for
• Aeration, permeability, root growth
• Water availability
• Biological habitat (plant roots and
  microorganisms)

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• Methodology
• undisturbed samples flow through analysis

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13 Year Tillage Experiments

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Rotation Experiment

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Comparison of two NY Vegetable Farms Hamlin Silt
Loam

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Roots can be unhealthy due to...

• Poor soil drainage
• Poor nutrient availability
• Soil compaction
• Plant pathogen infection by
• Rhizoctonia
• Fusarium
• Pythium
• Thielaviopsis
• Etc.

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Soil Bioassay w/ Bean for Assessing Soil Health
Beans grown in greenhouse 5 to 6 weeks
Soil collection
Root rot severity rating
(1 healthy to 9 primary roots rotted)
Bean roots are washed
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Organic vs Conventional Vegetable Production
Systems New York Commercial Vegetable Growers
2004 and 2005
Number of Samples
Root Rot Severity Rating
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IPM Systems Comparison Site NYSAES, Geneva, NY
(C. Petzoldt et al.)
Root Rot Severity Rating
Organic
IPM-present
IPM-future
Conventional
Production System
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Potentially Mineralizable Nitrogen (PMN)

• Indicator for capacity of soil microbes to
  convert N tied up in complex organic residues
  into plant-available forms (ammonium and nitrate)
• Technique Soil is measured for total N,
  ammonium-N, nitrate-N at sampling and after a
  7-day incubation
• Interpretation Positively correlated with OM,
  aggregate stability, beneficial nematodes.

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Available or Active Carbon (C)

• Indicator for Fraction of C and nutrients in
  total OM that is actually available for soil food
  web and plants. Shows response to soil mgmt
  sooner than total OM changes can be detected.
• Technique Measure C in specific OM fractions
  separated by wet-sieving (shown in photo), or by
  a more rapid, cheaper colorimetric technique that
  oxidizes only active C.
• Interpretation Positively correlated with OM,
  and with measures of biological activity

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Weed Seed Bank Index

• Indicator for Weed seed pressure from common
  broadleaf species and grasses.
• Technique Still in research phase. Composite
  soil samples are spread in thin layer in small
  flats and monitored for 4 weeks for number of
  selected common broadleaf species, grasses, and
  other. A cold treatment may be used to test for
  weed species requiring vernalization.
• Interpretation Will be primarily useful for
  tracking a farm over time to see if new practices
  are effectively reducing the seed bank

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Decomposition Rate

• Indicator for capacity of soil microbial
  community to breakdown crop residue
• Technique Moist, sieved soil placed in petri
  dish with cellulose filter paper rate of
  breakdown monitored weekly by counting grid cells
  degraded, or by digital imaging.
• Interpretation Positively correlated with OM
  (e.g., muck soils have very high rates), and with
  other measures of soil biological activity.

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Effect of Cropping System on Selected Soil
Health Indicators (2004)
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Visible-Near-Infrared Hyperspectral Sensing
?
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Timing of Sampling Does it affect Indicators
Values?

YES, for most soil quality indicators. Early
spring sampling is recommended.
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Criteria for Selecting Soil Health Indicators

• Sensitivity to management
• Functional relevance
• Consistency and reproducibility
• Ease (cost) of sampling
• Cost of analysis
• Opportunity to be estimated by statistical
  correlation

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Two-Tiered Soil Health Assessment

• Tier 1
• Standard soil health test
• 40-60 per sample
• based on disturbed soil samples (with use of
  sampling ring)
• includes in-field penetrometer readings
• Tier 2
• Based on purpose and site-specific needs
• Undisturbed soil samples
• Higher and variable cost, with a la carte
  options

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Field Sampling(early spring)
TIER 1 10 cores in a bag
TIER 2 5 cores in rings
TIER 12 54 penetrations, 3 depths
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TIER 1 LAB ANALYSES(prices are tentative)
VNIR reflectance
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TIER 2 LAB ANALYSES(prices are tentative)
VNIR reflectance
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High Quality Soil (physical and biological)
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Medium Quality Soil (physical and biological)
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Low Quality Soil (physical and biological)
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Linking Indicators to Constraints

• ROOT ROT RATING SUSCEPTIBILITY TO ROOT DISEASES
  
• ACTIVE CARBON ENERGY STORAGE, ABILITY TO SUPPORT
  SOIL ORGANISMS
• POTENTIALLY MINERALIZABLE NITROGEN ABILITY TO
  SUPPLY NITROGEN
• AGGREGATE STABILITY WATER INFILTRATION AND
  TRANSMISSION PREVENTION OF RUNOFF AND EROSION
  RESISTANCE TO HARDSETTING AND CRUSTING, AERATION
• BULK DENSITY AERATION, ROOT PROLIFERATION,
  ORGANISM MOBILITY
• AVAILABLE WATER CAPACITY WATER STORAGE AND
  RELEASE
• PENETROMETER READINGS SHALLOW AND DEEP ROOT
  PROLIFERATION, DRAINAGE

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Linking Indicators to Management

• HIGH ROOT ROT RATING proper rotation, cover
  crops
• LOW ACTIVE CARBON cover crops, sod rotation
  crops, manure, compost
• LOW POTENTIALLY MINERALIZABLE NITROGEN add OM,
  leguminous cover/rotation crops
• LOW AGGREGATE STABILITY reduce tillage,
  shallow-rooted cover/sod crops, manure
• HIGH BULK DENSITY add OM through cover crops,
  perennial sod crops, manure, compost limited
  soil loosening
• LOW AVAILABLE WATER CAPACITY add stable OM
  (compost) reduce tillage
• HIGH PENETROMETER READINGS deep tillage/zone
  building, deep-rooted cover crops

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Whats Next?

• Develop service lab infrastructure
• Expand into Northeast Region (NE SARE)
• Further test methodologies (incl. VNIR)
• Further develop database
• Link soil health to soil value

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Funding

• Northern New York Agricultural Development
  Program
• USDA Northeast Sustainable Agriculture Research
  and Extension Program (SARE)