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Soil sampling requirements in Virginia

Soil sampling requirements in Virginia

State rules: 4VAC50-85, Nutrient Management Training and Certification Regulations and 9VAC25-192, VPA Regulation and General Permit for Animal Feeding Operations and Animal Waste Management. State guidance: Virginia Cooperative Extension, Soil Sampling Instructions for the Farm.

Soil sampling in Virginia: frequency, area, depth and cores

How often do you need to soil sample in Virginia?

When in the year should soil be sampled in Virginia?

How many acres can one soil sample cover in Virginia?

How deep should soil samples be taken in Virginia?

How many cores go into one soil sample in Virginia?

How many soil samples does a 100-acre field need in Virginia?

Nutrient Management Training and Certification Regulations: A uniform 100-acre field needs at least 5 composite samples of no more than 20 acres each.

Samples and cores for any field size

Soil sampling rules in Virginia, with the exact wording of each source
Country / region Purpose / programme Time / frequency Area per sample Method Depth Cores Status and source
United States
VirginiaUnited StatesVirginia only. Other states set their own rules.Soil analysis behind a nutrient management planNutrient Management Training and Certification Regulations
  • Result valid Dated no more than 3 years before the plan begins
  • Repeat The plan must recommend soil analysis for each field at least once every 3 years
A composite sample should represent up to about 20 acres (8.09 ha). Strip-cropped fields may be combined where soils, cropping history and fertility are similar.Representative results by standard sampling and analysis methods (Methods of Soil Analysis, Part 3, 1996). Subfield grids or management zones may be used.Fields not tilled in the past 3 years: 0 to 4 inches (0 to 10.16 cm). Fields tilled in the past 3 years: 0 to 6 inches (0 to 15.24 cm).Not specifiedConditional4VAC50-85-140, Required nutrient management plan procedures
Who it applies to, the exact wording and every source
Who it applies to
Binds certified nutrient management planners, for the plans they write under Virginia’s voluntary certification program. It does not by itself require a farm to sample: a farm is covered only where it follows such a plan, and other laws, permits or contracts decide which farms must have one.
Laboratory and analysis
Mehlich I extraction for phosphorus, or other methods and laboratories approved by the department and correlated to Mehlich I.
In force from
20 November 2014
Legal text
4VAC50-85, Nutrient Management Training and Certification Regulations, 4VAC50-85-140 A 2 f and D 4

The wording in the source

Timing

  • Soil analysis results shall be dated no more than three years prior to the beginning date of the nutrient management plan.

    4VAC50-85-140 A 2 f

  • Soil analysis shall be recommended for each field at least once every three years to determine the soil fertility and pH, and to update the nutrient management plan.

    4VAC50-85-140 D 4

Area per sample

  • A single composite soil sample should represent an area up to approximately 20 acres.

    4VAC50-85-140 A 2 f

  • Fields such as those common to strip cropping may be combined when soils, previous cropping history, and soil fertility are similar.

    4VAC50-85-140 A 2 f

Method

  • Representative soil analysis results for fields shall be determined by using standard soil sampling and analysis methods according to Methods of Soil Analysis, Part 3, Chemical Methods, 1996

    4VAC50-85-140 A 2 f

  • Soil sampling of fields based on subfield grids or management zones may be utilized.

    4VAC50-85-140 A 2 f

Depth

  • Representative soil sample cores shall be obtained from the soil surface to a depth of four inches (0-4") for fields that have not been tilled within the past three years

    4VAC50-85-140 A 2 f

  • and from the soil surface to a depth of six inches (0-6") for fields that are tilled or have been tilled within the past three years.

    4VAC50-85-140 A 2 f

Who it applies to

  • This chapter governs the department’s voluntary Nutrient Management Training and Certification Program for individuals who prepare nutrient management plans.

    4VAC50-85-20 A

  • A certified nutrient management planner shall include, in each plan, nutrient application practices for each field in the plan.

    4VAC50-85-140 A 1

  • Representative soil analysis results for fields shall be determined by using standard soil sampling and analysis methods

    4VAC50-85-140 A 2 f

Laboratory and analysis

  • utilizing the Mehlich I extraction procedure for phosphorus or other methods and laboratories approved by the department and correlated to Mehlich I

    4VAC50-85-140 A 2 f

In force

Sources

Sources re-checked every two months, last update October 2026. Reviewed by GeoPard editorial team.
VirginiaUnited StatesVirginia only. Other states set their own rules.Soil monitoring on animal waste land application sitesVirginia Pollution Abatement (VPA) general permit for animal feeding operations and animal waste management
  • Repeat Once every 3 years (1/3 years)
Not specifiedComposite samples. pH, phosphorus, potash, calcium and magnesium.0 to 6 inches (0 to 15.24 cm), unless the approved nutrient management plan says otherwiseNot specifiedConditional9VAC25-192-70, Contents of the general permit
Who it applies to, the exact wording and every source
Who it applies to
Owners of animal feeding operations with 300 or more animal units using a liquid manure collection and storage system, and animal waste end-users (Part III), once the department accepts their registration for the VPA general permit. Applies on their land application sites.
Laboratory and analysis
Methods specified in the approved nutrient management plan. Monitoring data kept on site for five years.
In force from
Under review
Legal text
9VAC25-192, VPA Regulation and General Permit for Animal Feeding Operations and Animal Waste Management, 9VAC25-192-70, Part I A 8 and A 9, Table 2 (Part III repeats them for animal waste end-users)

The wording in the source

Timing

Method

Depth

  • Soil monitoring shall be conducted at a depth of between 0-6 inches, unless otherwise specified in the approved nutrient management plan written for the animal feeding operation.

    Part I A 9

Who it applies to

  • owners of animal feeding operations having 300 or more animal units utilizing a liquid manure collection and storage system

    9VAC25-192-70, general permit cover page

  • Any owner or animal waste end-user whose registration statement is accepted by the department will receive the following general permit and shall comply with the requirements of the general permit

    9VAC25-192-70, opening paragraph

  • Soil at the land application sites shall be monitored as specified in Table 2 of Part I.

    Part I A 8

  • Soil at the land application sites shall be monitored as specified in Table 2 of Part III.

    Part III A 8 (animal waste end-users)

Laboratory and analysis

  • Analysis of soil and waste shall be according to methods specified in the approved nutrient management plan written for the animal feeding operation.

    Part I A 11

  • All monitoring data collected as required by this section and any additional monitoring shall be maintained on site for a period of five years

    Part I A 12

Sources

Sources re-checked every two months, last update October 2026. Reviewed by GeoPard editorial team.
VirginiaUnited StatesVirginia only. Other states set their own rules.Routine soil fertility samplingVirginia Cooperative Extension, Soil Sampling Instructions for the Farm
  • Season Fall sampling suggested, so lime can go on before the next season
  • Wait At least 6 to 8 weeks after liming or fertilizing
Areas of 5 to 10 acres (2.02 to 4.05 ha) where fields vary. Precision grids typically 2.5 acres, 1 acre on small fields.Zig-zag across each uniform area. Grid sampling, typically 2.5 acres, or smart sampling by topography, yield or soil map unit.Cropland: plow depth, 6 to 8 inches or more (15.24 to 20.32 cm). Pasture and no-till crop fields: 2 to 4 inches (5.08 to 10.16 cm).20 or more places per field, and at least 5 cores per acre represented. Grid points: 6 to 8 subsamples.Official guidanceVirginia Cooperative Extension SPES-141NP (PDF)
Who it applies to, the exact wording and every source
Who it applies to
Advice from the public land-grant university extension service for Virginia. Not law.
In force from
Under review
Legal text
Virginia Cooperative Extension SPES-141NP, Soil Sampling Instructions for the Farm (2019)

The wording in the source

Timing

  • Sampling in the fall allows time to apply lime to adjust the soil pH before next year’s growing season

    SPES-141NP, step 2

  • For areas recently limed or fertilized, delay sampling at least six to eight weeks.

    SPES-141NP, step 2

Area per sample

Method

  • Zig-zag across the field or area as shown in the diagram.

    SPES-141NP, step 4

  • “Smart sampling” consists of sampling those areas of the field that are obviously different, such as with respect to topography (hilltops, low areas), or if a combine yield monitor has been used, high-yielding and low-yielding areas in the field.

    SPES-141NP, precision farming

  • If the field has been mapped, it can be divided by soil series (i.e., soil mapping unit).

    SPES-141NP, precision farming

Depth

  • The desired depth for cropland is plow depth (6 to 8 inches or more), and 2 to 4 inches for pasture land, or no-till crop fields.

    SPES-141NP, step 5

Cores

Sources

Sources re-checked every two months, last update October 2026. Reviewed by GeoPard editorial team.

United States: federal rules and every other state

Soil sampling regulations in every country

Report an outdated requirement: info@geopard.tech

Plan the points to the rule that applies

Set the area per sample, the cores and the depth your rule asks for. GeoPard places the points on a grid or by zone, routes the walk, prints the labels and takes the plan to the field on a phone.

Create a sampling plan See the Soil Sampling Planner

A planning reference built from official sources, not legal advice. Rules apply by jurisdiction, nutrient, land use and programme: check the current official text and your laboratory’s instructions before fieldwork.

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