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

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)

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

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

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

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

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

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 MEASUREMENTS DISTURBED SAMPLE UNDISTURBED SAMPLE

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

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

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

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)

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

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?)

Rotation Experiment 9.5

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

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 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

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

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

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 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

Visible-Near-Infrared Hyperspectral Sensing ?

Timing of Sampling: Does it affect Indicators Values? 7 or 9.5 min 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 “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 1: 10 cores in a bag TIER 1+2: 5*4 penetrations, 3 depths TIER 2: 5 cores in rings

TIER 1 LAB ANALYSES (prices are tentative) VNIR reflectance

TIER 2 LAB ANALYSES (prices are tentative) VNIR reflectance

High Quality Soil (physical and biological)

Medium Quality Soil (physical and biological)

Low Quality Soil (physical and biological)

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)