Soil sampling requirements in South Dakota

Q: How many soil samples does a 100-acre field need in South Dakota?

Under SDSU Extension, Recommended Soil Sampling Methods for South Dakota: A uniform 100-acre field needs at least 40 composite samples of no more than 2.5 acres each, and at least 240 cores in all, 6 per sample.

State guidance: SDSU Extension, Recommended Soil Sampling Methods for South Dakota.

Soil sampling in South Dakota: frequency, area, depth and cores

How often do you need to soil sample in South Dakota?

SDSU Extension, Recommended Soil Sampling Methods for South Dakota Official guidance P, K, pH, salts, Ca, Mg and micronutrients every 2 to 3 years. Nitrate every year before non-legume crops.

When in the year should soil be sampled in South Dakota?

SDSU Extension, Recommended Soil Sampling Methods for South Dakota Official guidance Mobile nutrients, nitrate in particular: late fall once soil is below 50 F, winter, or early spring. Most other tests any time of year.

How many acres can one soil sample cover in South Dakota?

SDSU Extension, Recommended Soil Sampling Methods for South Dakota Official guidance Grid cells no larger than 2.5 acres (1.01 ha).

How deep should soil samples be taken in South Dakota?

SDSU Extension, Recommended Soil Sampling Methods for South Dakota Official guidance 0 to 6 inches (0 to 15.24 cm) for P, K, pH, organic matter, soluble salts, zinc, iron, manganese, copper and boron. For mobile nutrients such as nitrate, chloride and sulfur, a 24 inch sample split into 0 to 6 and 6 to 24 inches (15.24 to 60.96 cm).

How many cores go into one soil sample in South Dakota?

SDSU Extension, Recommended Soil Sampling Methods for South Dakota Official guidance At least 15 cores for a whole field or a zone. A grid sample is usually 6 to 8 cores.

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

SDSU Extension, Recommended Soil Sampling Methods for South Dakota: A uniform 100-acre field needs at least 40 composite samples of no more than 2.5 acres each, and at least 240 cores in all, 6 per sample.

Samples and cores for any field size

Soil sampling rules in South Dakota, with the exact wording of each source
Country / region	Purpose / programme	Time / frequency	Area per sample	Method	Depth	Cores	Status and source
United States
South DakotaUnited StatesSouth Dakota only. Other states set their own rules.	Routine soil fertility and nitrate samplingSDSU Extension, Recommended Soil Sampling Methods for South Dakota	Repeat P, K, pH, salts, Ca, Mg and micronutrients every 2 to 3 years. Nitrate every year before non-legume crops. Season Mobile nutrients, nitrate in particular: late fall once soil is below 50 F, winter, or early spring. Most other tests any time of year.	Grid cells no larger than 2.5 acres (1.01 ha)	Whole field composite, a grid of 2.5 acres or less, or directed zone sampling by landscape, yield, imagery or soil conductivity.	0 to 6 inches (0 to 15.24 cm) for P, K, pH, organic matter, soluble salts, zinc, iron, manganese, copper and boron. For mobile nutrients such as nitrate, chloride and sulfur, a 24 inch sample split into 0 to 6 and 6 to 24 inches (15.24 to 60.96 cm).	At least 15 cores for a whole field or a zone. A grid sample is usually 6 to 8 cores.	Official guidanceSDSU Extension P-00132 (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 South Dakota. Not law. In force from Under review Legal text SDSU Extension P-00132, Recommended Soil Sampling Methods for South Dakota (September 2019) The wording in the source Timing In general, soil tests for P, K, pH, soluble salts, calcium (Ca), magnesium (Mg), and micronutrients will change very little from year to year and need to be analyzed only every 2 to 3 years. P-00132 p. 1, When and how often to sample In contrast, levels of NO3-N can change dramatically from year to year and should be analyzed every year prior to planting non-legume crops. P-00132 p. 1, nitrate In summary, a soil sample for most soil tests can be taken anytime during the year. P-00132 p. 2, summary For most mobile nutrients, in particular NO3-N, samples should be taken in late fall (when soil temperatures are below 50° F), in winter, or in early spring. P-00132 p. 2, summary Area per sample the largest grid size that will adequately measure nutrient variability for a field should be no more than 2.5 acres in size. P-00132 p. 5, Grid sampling Method Fields may be divided into smaller parcels or “zones” or sampled as a whole field. P-00132 p. 4, Field sampling methods The field is divided into rectangular grids and a sample is taken from each grid. P-00132 p. 5, Grid sampling Detailed information about a field, such as yield monitor maps, remote sensing imagery, digital soil survey or topographic maps, and/or electrical conductivity data, can all help define nutrient management zones. P-00132 p. 5, Directed sampling Depth A 0-6 inch sample is recommended for P, K, pH, organic matter, soluble salts, zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), and boron (B). P-00132 p. 2, Nutrients A deep sample (24-inch) is recommended for mobile nutrients such as NO3-N, chloride (Cl), and sulfur … P-00132 p. 2, Nutrients It is recommended to separate deep samples (0-24 inch) into two separate samples; one representing the 0-6 inch depth and the other a 6-24 inch depth (Figure 2). P-00132 p. 2, Nutrients Cores taking at least 15 random cores from the field and compositing (mixing) by depth increment P-00132 p. 4, Whole field composite method Each grid sample is usually a composite of 6 to 8 cores. P-00132 p. 5, Grid sampling A field with four landscape zones would have four separate samples, each with a minimum of 15 cores. P-00132 p. 6 Sources SDSU Extension P-00132 (PDF) Guidance 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.

Products

AI Reasoning Assistant NEW

Automated Yield Report NEW

Management Zones & VRA Maps

Crop Monitoring

Topography analytics

3D Maps

Scouting

Soil data analytics

Farm View: Field Benchmarking NEW

As-Applied & As-Planted Data

Yield Data

BY ROLE

For Growers

For Ag Consultants & Service Companies

For Cooperatives & AgriHoldings

For Ag Input Producers & Dealers

For Ag Equipment Producers & Dealers

For AgTech Companies

For Science and Education

BY USE-CASE

Carbon Farming

Biodiversity

Products

By Role

By Use-case

Precision Agriculture API

GeoPard MCP

White Label Solutions

Widgets

MyJohndeere Ops Center Connected

Blog

One Pager Pdf

Sustainability

Distributors & Partners

Documentation

Tutorial - Web

Tutorial - Mobile

Data Compatibility

About Us

API documentation

Product Releases

Newsletters

Newsletters

Soil sampling requirements in South Dakota

Soil sampling requirements in South Dakota

Soil sampling in South Dakota: frequency, area, depth and cores

How often do you need to soil sample in South Dakota?

When in the year should soil be sampled in South Dakota?

How many acres can one soil sample cover in South Dakota?

How deep should soil samples be taken in South Dakota?

How many cores go into one soil sample in South Dakota?

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

The wording in the source

Timing

Area per sample

Method

Depth

Cores

Sources

Plan the points to the rule that applies

Service without extra costs

Get Demo