1. Soil Health Assessment on New York Vegetable Farms
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

2. Aspects of Soil Health Inherent soil quality Dynamic soil quality
Results from natural soil forming processes and factors
Dynamic soil quality
Changes due to human use and management
interaction
There are two ways to view the quality of soils.
(Pierce and Larson, 1993)

3. 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

4. How Healthy is a Soil?
How to measure?
2. Which are meaningful indicators?
3. What are appropriate sampling protocols?

5. Soil Health Indicators
Bulk density
Penetration resistance
Aggregate stability
Water infiltration rate
Water holding capacity
Pore size distribution
% OM
“Active” C, N in OM
Cation exchange capacity
N, P, K
Micronutrients
[Toxins, pollutants]
[Glomalin]
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

6. Soil health testing procedures must be:
Rapid
Inexpensive
Scientifically meaningful
Agronomically useful
2min

7. Our Approach: Research Farm Experiments Commercial Farm Samples
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

8. 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

9. Field Measurements
PENETRABILITY
INFILTRABILITY

10. LAB MEASUREMENTS
DISTURBED SAMPLE
UNDISTURBED SAMPLE

11. Aggregates:
Creating and protecting these crumbs keeps the soil open to rain and to air exchange.

12. Methodology: Aggregate Stability disturbed samples
WSAlg
2mm sieve
2-8mm aggregates
WSAsm 0.25mm sieve
0.25-2mm aggregates
The Cornell Sprinkler
0.5m above
sample aggregates on sieves
Aggregates before
stability test
wetting
soil aggregates
1.25cm rainfall in 5 min, providing Energy of 0.142mJ/drop, total of 2.5J/sieve
3.5

13. Results and Interpretation of Aggregate Stability Test
% of Soil crumbs stable to 1.25cm rain/5mins:
Organic
management
~70% - high
Conventional management
~20% - low
CONCLUDE that A.S. can serve as a valuable meaningful easily cheaply measured indicator which can give an indication of on-farm problems.
2mm sieves
Aggregates after stability test

14. Soil Pores Aggregate (crumb) Porosity is important for:
large pore
intermediate
pore
small pore
Aggregate (crumb)
Soil Pores
Porosity relates to aeration, Water availability, permeability, rootgrowth
Biological habitat
Porosity is important for:
Aeration, permeability, root growth
Water availability
Biological habitat (plant roots and microorganisms)

15. Methodology undisturbed samples – flow through analysis
Penetration
Resistance
(PR)
4mm micro-penetrometer
Sand Suction Table at
Ψ = -10kPa
(Field Capacity)
High-Pressure Chamber at
Ψ = -1500kPa
(wilting point)
Pore Size Distribution
Constant
Head
Method
Saturated Hydraulic Conductivity (Ks)
Bulk Density
(dried at 105oC) 5

16. 13 Year Tillage Experiments
6.5
Where wider end of triangle shows which treatment has higher value (so we wouldn’t lose the soil health interpretation part… but then again maybe I just don’t have time to talk about it?)

17. Rotation Experiment
9.5

18. Comparison of two NY Vegetable Farms
Hamlin Silt Loam
Use controlled sites to interpret farm indicator values…

19. Roots can be unhealthy due to...
Poor soil drainage
Poor nutrient availability
Soil compaction
Plant pathogen infection by
Rhizoctonia
Fusarium
Pythium
Thielaviopsis
Etc.

20. Soil Bioassay w/ Bean for Assessing Soil Health
Bean seed planted in field soil
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

21. Root Rot Severity Rating
Organic vs Conventional Vegetable Production Systems New York Commercial Vegetable Growers 2004 and 2005
Good
Moderate
Poor
Number of Samples
Root Rot Severity Rating

22. IPM Systems Comparison Site NYSAES, Geneva, NY (C. Petzoldt et al.)
Root Rot Severity Rating
Conventional
Organic
IPM-present
IPM-future
Production System

23. 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.

24. 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

25. 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

26. 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.

27. Effect of Cropping System 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
5.4 a
1.73 a
9.0 a
Organic
Veg/rye
4.5
6.18
17.0
Veg/rye-vetch
4.8
5.78
20.0
Conv
Veg/manure
2.32
0.47
3.9
VegAlfalfa
3.06
1.20
10.0

28. Visible-Near-Infrared Hyperspectral Sensing?

29. Timing of Sampling: Does it affect Indicators Values?
7 or 9.5 min
YES, for most soil quality indicators.
Early spring sampling is recommended.

30. 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

31. Two-Tiered Soil Health Assessment
“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

32. Field Sampling (early spring)
TIER 1:
10 cores in a bag
TIER 1+2:
5*4 penetrations, 3 depths
TIER 2:
5 cores in rings

33. TIER 1 LAB ANALYSES (prices are tentative)
VNIR reflectance

34. TIER 2 LAB ANALYSES (prices are tentative)
VNIR reflectance

35. High Quality Soil (physical and biological)

36. Medium Quality Soil (physical and biological)

37. Low Quality Soil (physical and biological)

38. 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

39. 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

40. 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”

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