Science · Soils
Organic & Peat Soils
Soils high in organic matter that hold very large amounts of water but can subside and become water-repellent when dried.
Profile
- Material
- Organic-rich soil or peat; determine carbon content, thickness, decomposition and classification rather than using a universal 20% organic-matter cutoff.
- Physical behavior
- Density and retention depend on decomposition, shrinkage and material composition.
- Drainage risk
- Aeration of peat can accelerate oxidation and subsidence.
Source: USDA Soil Survey Manual (2017), Chapter 3: Examination and Description of Soil Profiles ↗ — Organic Soils and Organic Soil Materials sections: decomposition, fiber and material definitions. No universal 20% organic-matter criterion.
Classification or material name does not establish field capacity, permanent wilting point, salinity, fertility or a calibrated sensor irrigation target. Symptoms are investigation prompts, not diagnoses.
Water & soil context
- Moisture (VWC)
- No universal field-capacity or permanent-wilting-point VWC for this label. Measure retention and field dry-down at relevant depths; validate sensor response for the installed material.
- Salinity tolerance
- Determine salinity from an appropriate laboratory EC method and irrigation-water chemistry; texture/order alone does not establish salt status.
- Drought tolerance
- Available storage depends on retention, rooting depth, restrictive layers and vegetation demand.
Assess water table, aeration, shrinkage and rewetting; avoid prescribing either permanent saturation or complete drying for every peat use.
Source: Hydrophobic Soil? #722976 — Ask Extension ↗ — Expert response: dry peat can be hydrophobic and slow to moisten. Practical case evidence, not a quantitative retention study.
Source: Soil moisture sensors for irrigation scheduling — University of Minnesota Extension ↗ — Sections on volumetric sensors, calibration, field capacity and allowable depletion. Supports site-specific sensor interpretation, not a universal texture/order VWC threshold or any product performance claim. Verification: direct HTTP fetch blocked (403); publication title and relevant content verified through indexed search text, not a full-text inspection.
Problems to watch
- Subsidence
- Water repellency
- Nitrogen release swings
Stress signs
- Dry crust that won't rewet
Source: Histosols — USDA NRCS ↗ — Organic accumulation and accelerated decomposition/subsidence after drainage. Peat material is not automatically a classified Histosol.
Where you'll find it
- Wetland-edge sites
- Specialty agriculture
Sources & scope
- USDA Soil Survey Manual (2017), Chapter 3: Examination and Description of Soil Profiles ↗
Organic Soils and Organic Soil Materials sections: decomposition, fiber and material definitions. No universal 20% organic-matter criterion.
- Histosols — USDA NRCS ↗
Organic accumulation and accelerated decomposition/subsidence after drainage. Peat material is not automatically a classified Histosol.
- Hydrophobic Soil? #722976 — Ask Extension ↗
Expert response: dry peat can be hydrophobic and slow to moisten. Practical case evidence, not a quantitative retention study.
- Soil moisture sensors for irrigation scheduling — University of Minnesota Extension ↗
Sections on volumetric sensors, calibration, field capacity and allowable depletion. Supports site-specific sensor interpretation, not a universal texture/order VWC threshold or any product performance claim. Verification: direct HTTP fetch blocked (403); publication title and relevant content verified through indexed search text, not a full-text inspection.
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All Science profilesPublished botanical and soil references are distinct from GroundWorx product guidance. Moisture thresholds and monitoring depths require site calibration; sources do not establish product performance or diagnose stress.