Linda Poole

NCAT Regenerative Grazing Specialist
NCAT Sustainable Ag Specialist Lee Rinehart put together a useful resource for producers investigating residual ag chemicals in their soils. In case you have trouble downloading the attached file, I've also pasted Lee's information below. Thank you, Lee, for putting together and sharing this resource!

Chemical testing for residues in agricultural soils

Past use of persistent organic pesticides, e.g. DDT and dieldrin, means that some agricultural soils are contaminated with chemical residues. In broadacre farming, these chemicals were used directly on soil or applied to crops, contaminating soil via runoff or spray drift. Similarly, arsenic used in cattle and sheep dip baths has contaminated soils around these facilities. Pesticide contamination may cause residues in stock or crops raised on affected land. Soil residue tests determine if pesticides are present and at what levels, so that the risk to livestock or crops can be assessed and managed. The core purpose of managing chemical residues is to minimize risk to the human food chain from grazing animals (1).
Other resources

A bioassay is a technique for determining if herbicide (or other chemical) residues are present and bioavailable in soil or water at high enough concentrations to adversely affect plant growth. This is a simple, economical, and direct method to determine if it is safe to seed or plant into areas previously treated with herbicides or into soil with an unknown history of herbicide use. In its simplest form, a bioassay uses susceptible plants to identify if the herbicide is present in concentrations high enough to inhibit germination and/or alter plant growth. However, scientists sometimes use sensitive bioassay species to estimate herbicide concentrations in soil and water, and to identify unknown herbicide residues from exhibited injury symptoms (2).

Conducting a Bioassay For Herbicide Residues | NC State Extension Publications (

Check your soil for herbicide residue - Grainews


Testing soils for residues of persistent chemicals, July 2017, Primefact 320, third edition. Animal Biosecurity and Welfare, NSW DPI
Conducting a Bioassay For Herbicide Residues, NC State Extension


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