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 Wolfe
Departments of Crop and Soil Sciences, Horticulture, and Plant Pathology
Soil Health Assessment on New York Vegetable Farms
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(Pierce and Larson, 1993)
interaction
Soil Health and Processes
Physical Chemical
Biological
•Nutrient retention and release
• N
• P, K, Ca, Mg, etc.
• micronutrients
• pH
•Energy (C) storage
•Toxicity prevention
•Root proliferation, organismal locomotion
•Aeration
•Water retention
•Water infiltration and transmission; erosion prevention
•Pest suppression
•N mineralization
•OM decomposition
•Habitat protection
How Healthy is a Soil?How Healthy is a Soil?
1.1. How to measure?How to measure?2. Which are meaningful indicators?2. Which are meaningful indicators?3. What are appropriate sampling 3. What are appropriate sampling
protocols?protocols?
Soil Health Indicators
Physical Chemical
Biological
• % 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
• Soil disease suppressive capacity
• Beneficial and pathogenic nematodes, [other pathogens]
• N mineralization rate (PMN)
• Decomposition rate• microbial biomass• Respiration rate• Earthworm counts • Genetic diversity
Soil health testing procedures must be:
Rapid Inexpensive Scientifically
meaningful Agronomically
useful
Our Approach:Our Approach:
Research Farm ExperimentsResearch Farm ExperimentsProvide scientific basis from controlled trials to establish useful indicators
Commercial Farm SamplesProvide real-world perspective under range of conditions
~700 SAMPLES WERE ANALYZED FOR MULTIPLE POTENTIAL SOIL HEALTH INDICATORS
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
Field Measurements
PENETRABILITY INFILTRABILITY
LAB MEASUREMEN
TS
DISTURBED SAMPLE
UNDISTURBED SAMPLE
Aggregates: Creating and protecting these crumbs keeps the soil
open to rain and to air exchange.
Methodology: Aggregate Methodology: Aggregate Stability Stability disturbed samplesdisturbed samples
The Cornell Sprinkler 0.5m above
sample aggregates on sieves
Aggregates before stability test
WSAlg 2mm sieve
2-8mm aggregates
WSAsm
0.25mm sieve
0.25-2mm aggregates
1.25cm rainfall in 5 min, providing Energy of
0.142mJ/drop, total of
2.5J/sieve
wetting soil aggregates
Results and Interpretation Results and Interpretation of Aggregate Stability Testof Aggregate Stability Test
% of Soil crumbs stable to 1.25cm rain/5mins:
Organic management ~70% - high
Conventional management ~20% - low
Aggregates after stability test2mm sieves
large pore
intermediatepore
small pore
Aggregate (crumb)
Porosity is important for:• Aeration, permeability, root growth• Water availability• Biological habitat (plant roots and
microorganisms)
Soil Pores
MethodologyMethodologyundisturbed samples – flow through analysisundisturbed samples – flow through analysis
Constant Head
Method
Saturated Hydraulic Conductivity (Ks)
Sand Suction Table at
Ψ = -10kPa (Field
Capacity)
High-Pressure Chamber at
Ψ = -1500kPa (wilting point)
Pore Size Distribution
PenetrationResistance
(PR)
4mm micro-penetrometer
Bulk Density(dried at 105oC)
13 Year Tillage Experiments 13 Year Tillage Experiments
Indicators showing
agricultural management
difference (p<0.05): Plow Till No Till Plow Till No Till
Bulk Density (g cm-3) ns ns 1.21 1.03
Pores > 30µm (%) 13 17 12 16
Pores > 0.1µm (%) ns ns 29 34
AWC (%) 12 16 ns ns
WSAsm (%) 20 41 30 68
Silt Loam Clay Loam
(Aurora) (Willsboro)
Rotation ExperimentRotation Experiment
Indicators showing
agricultural management Corn after Continuous Corn after Continuous
difference (p<0.05): Grass Corn Grass Corn
Bulk Density (g cm-3) 1.31 1.36 ns ns
Pores > 30µm (%) ns ns 10 16
Pores > 0.1µm (%) 42 38 ns ns
AWC (%) 28 23 24 20
WSAlg (%) 34 10 ns ns
WSAsm (%) 40 32 65 33
Loamy Sand Sandy Clay
Comparison of two NY Comparison of two NY Vegetable FarmsVegetable Farms
Hamlin Silt LoamHamlin Silt Loam
Physical Soil Health Indicator: Conventional OrganicAggregate Stability (%) 20 70Total Porosity (%) 45 59Macroporosity (%) 2.8 4.0Bulk Density (g/cc) 1.4 1.2Penetration Resistance (MPa) 1.2 0.8
Management:
Roots can be unhealthy due to...
Poor soil drainage Poor nutrient availability Soil compaction Plant pathogen infection by
Rhizoctonia
Fusarium
Pythium
Thielaviopsis
Etc.
Soil Bioassay w/ Bean for Assessing Soil HealthSoil Bioassay w/ Bean for Assessing Soil Health
Soil collectionSoil collection
Root rot severity rating (1 = healthy to 9 =
primary roots rotted)
Root rot severity rating (1 = healthy to 9 =
primary roots rotted)
Beans grown in greenhouse5 to 6 weeks
Beans grown in greenhouse5 to 6 weeks
Bean roots are washedBean roots are washed
Bean seed planted in field soil
Bean seed planted in field soil
Root Rot Severity RatingRoot Rot Severity Rating
Organic vs Conventional Vegetable Production Systems New York Commercial Vegetable Growers 2004 and 2005
Organic vs Conventional Vegetable Production Systems New York Commercial Vegetable Growers 2004 and 2005
0
5
10
15
20
25
30
35
40
1 2 3 4 5 6 7 8 9
Conventional production
Organic production
Num
ber
of S
ampl
esN
umbe
r of
Sam
ples
Good Moderate Poor
Conventional Organic IPM-present IPM-future
Ro
ot R
ot S
eve
rity
Ra
ting
Ro
ot R
ot S
eve
rity
Ra
ting
Production SystemProduction System
IPM Systems Comparison Site NYSAES, Geneva, NY (C. Petzoldt et al.)IPM Systems Comparison Site NYSAES, Geneva, NY (C. Petzoldt et al.)
aa
b b
c
ab
c
c
1
2
3
4
5
6
7
8
92002
2003
2004
2005
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.
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
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
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.
Effect of Cropping System Effect of Cropping System on Selected Soil Health Indicators (2004)on Selected Soil Health Indicators (2004)
Treatment Crop
Org Matter (%)
N Min Rate (ugN per g soil per wk)
Decomp Rate(% per wk)
Plow Corn Grain 4.0 b 1.48 b 3.0 b
No-Till Corn Grain 5.4 a 1.73 a 9.0 a
Organic Veg/rye 4.5 6.18 17.0
Organic Veg/rye-vetch
4.8 5.78 20.0
Conv Veg/manure
2.32 0.47 3.9
Conv VegAlfalfa
3.06 1.20 10.0
Visible-Near-Infrared Hyperspectral Sensing
?
Timing of Sampling:Timing of Sampling:Does it affectDoes it affect
Indicators Values?Indicators Values?
YES, for most soil quality indicators.Early spring sampling is recommended.
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
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
Field Sampling(early spring)
TIER 2:5 cores in rings
TIER 1:10 cores in a bag
TIER 1+2:5*4 penetrations, 3 depths
TIER 1 LAB ANALYSES(prices are tentative)
Physical ($15)/Sample Biological ($15-35)/Sample
Chemical ($10)/Sample
Bulk density (Composite 6 cores in a plastic bag)
Water Stable Aggregates (2 -0.25 mm)
Available Water Capacity (by measurement and estimation)
Textural class (by feel)
Field Penetration Resistance
Potentially Mineralizable Nitrogen ($10)
Active Carbon ($5)
Root Rot Assay ($15)
Weed assay (under development, $5)
Standard Chemical Test ($10)
VNIR reflectance
TIER 2 LAB ANALYSES(prices are tentative)
Physical ($45)/4 Cores Biological (up to $90) Chemical ($10+?)
Macro-, meso-, and micro-pores
Penetration resistance
Water stable aggregates
Textural class
Field penetration resistance
PMN ($10)
Active Carbon ($5)
Root Assay ($15)
Weed Bioassay (under dev, $5)
Nematode Assessment ($25)
Microbial Biomass ($20)
Respiration Rate ($10)
Field Earthworm Counts
Standard Chemical Test ($10)
Large selection of other a la carte analyses
VNIR reflectance
High Quality Soil (physical and biological)
Date: 2-8-06
INDICATORS Measured ValuesAverage
Rela RATING CONSTRAINTSCONSTRAINT
Sub-optimal
50th Pecentile
Optimal
Root Rot Rating 3.50 1
Potentially Mineralizable Nitrogen 24.27 2
Organic Matter (%) 4.21 1
Aggregate Stability 0.25 - 2mm (%) 50.50 2
Bulk Density (g/cc) 1.04 2
Available Water Capacity (m/m) 0.16 1
9F
Depth Value (Psi) Rating Symptom
0-6 inches 120 Low - Excellent
6-12 inches 160 Medium - Good
12-18 inches 200 Medium - Good
Sandy SoilsSoil Quality Rating Model by Cornell Soil Health Team
OVERALL QUALITY
Farm: Bob Fresh Veggies Field: East BarnSoil Type: Sandy Loam
Soil Texture: Sand Drainage: Good Percentile
Slope (%): 1%
out of 12 ( Low:0-4; Medium:5-8; High:9-12)
FIELD PENETROMETER ASSESSMENT
0 - Low; 1 -Medium; 2 -High
Medium Quality Soil (physical and biological)
Date: 2-8-06
INDICATORS Measured ValuesAverage
Rela RATING CONSTRAINTSCONSTRAINT
Sub-optimal
50th Pecentile
Optimal
Root Rot Rating 4.13 1
Potentially Mineralizable Nitrogen 1.20 0
Nitrogen Release and Microbial Activity
Organic Matter (%) 3.06 1
Aggregate Stability 0.25 - 2mm (%) 15.79 0
Water Intake and Transmission
Bulk Density (g/cc) 1.28 1
Available Water Capacity (m/m) 0.17 2
5F
Depth Value (Psi) Rating Symptom
0-6 inches 210 Medium - Good
6-12 inches 270 Medium - Good
12-18 inches 370 High - Bad Deep Compaction
Sandy SoilsSoil Quality Rating Model by Cornell Soil Health Team
OVERALL QUALITY
Farm: Bob Fresh Veggies Field: West BarnSoil Type: Sandy Loam
Soil Texture: Sand Drainage: Good Percentile
Slope (%): 1%
out of 12 ( Low:0-4; Medium:5-8; High:9-12)
FIELD PENETROMETER ASSESSMENT
0 - Low; 1 -Medium; 2 -High
Low Quality Soil (physical and biological)
Date: 2-8-06
INDICATORS Measured ValuesAverage
Rela RATING CONSTRAINTSCONSTRAINT
Sub-optimal
50th Pecentile
Optimal
Root Rot Rating 6.38 0Root Health
Potentially Mineralizable Nitrogen 5.68 1
Organic Matter (%) 3.73 1
Aggregate Stability 0.25 - 2mm (%) 31.56 1
Bulk Density (g/cc) 1.59 0
Root Proliferation, Hardsetting and
Crusting
Available Water Capacity (m/m) 0.13 0
Water storage
3F
Depth Value (Psi) Rating Symptom
0-6 inches 320 High - Bad Surface Compaction
6-12 inches 360 High - Bad Subsurface Pan
12-18 inches 400 High - Bad Deep Compaction
Sandy SoilsSoil Quality Rating Model by Cornell Soil Health Team
OVERALL QUALITY
Farm: Bob Fresh Veggies Field: North BarnSoil Type: Sandy Loam
Soil Texture: Sand Drainage: Good Percentile
Slope (%): 1%
out of 12 ( Low:0-4; Medium:5-8; High:9-12)
FIELD PENETROMETER ASSESSMENT
0 - Low; 1 -Medium; 2 -High
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
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
What’s 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”
Funding
Northern New York Agricultural Development Program
USDA Northeast Sustainable Agriculture Research and Extension Program (SARE)