Tools for Soil Diagnostics

Hands

Don’t overlook the value of a hands-on approach to diagnosing soil problems. Use a hand texturing chart to estimate the soil texture at the surface or throughout the depth of the soil profile. Hands can also be used to estimate the soil moisture content with the aid of the chart on pg. 31 of the Best Management Practices - Irrigation Management booklet.

Knife

Knives can be used to assess soil density or compaction. They can be used to probe the soil, find seeds, and estimate planting or tillage depth. They are also used to gage the severity of a soil crust. Keep a separate knife for soil diagnostics as soil will rapidly dull the edge on any blade.

Shovel, Spade and Hand Trowel

Shovels and hand trowels can be used to gather soil samples, check soil moisture, and assess soil structure. A spade is the recommended tool for use in the Visual Evaluation of Soil Structure, a simple framework for scoring soil structure quality. Use a shovel or spade to dig up and compare roots of both healthy and unhealthy plants to assess possible soil, disease, or insect related problems affecting the crop's growth.

Soil Probe

The soil probe is a highly versatile tool. It can be used to take soil samples for nutrient analysis. Standard soil samples are taken to a depth of 15 cm (6 in.) while soil nitrate samples are taken to 30 cm (1 ft.). Insert the probe straight into the soil to ensure an accurate depth of core.

A probe can also be used to check the soil profile for soil moisture status, resistance or compacted layers. Inspect the soil core for colour and textural changes through the profile. Avoid soil probes with foot pedals or select a probe that has a removable pedal. While the pedal assists with insertion, it also prevents the use of the probe for deeper profile sampling.

Soil Auger or “Dutch” Auger

Soil augers are available in a variety of diameters. Like the soil probe, an auger can be used to examine the soil profile with minimal disturbance. The curved blade is particularly useful for sampling in dry, stony, or coarse textured soils. Augers allow the gathering of samples for nutrient or chemical testing, soil moisture, or to assess texture, colour, stoniness, and presence of carbonates at depth.

Tile Probe

A tile probe is a straight, slightly flexible, steel rod approximately 1 to 1 1/2 metres (3-5 ft.) in length with a cross bar handle to allow for insertion and removal from the soil. The rod has a sharp, cone-shaped tip, with a diameter slightly greater than the rod to allow for easy insertion and minimal soil friction.

Tile probes can be used to locate tile or to locate compacted soil layers. Use the tile probe to test the suspected area to a depth of 50 cm (1 ½ ft.) and compare to a fencerow or unaffected area. Insert the tile probe into the ground at a slow and steady pace. Keep your arms slightly bent; they act as the pressure gauge feeling the force required to push the tip through the soil. Record the depths at which the tip of the probe meets resistance. Keep in mind that soil moisture plays a large part in soil strength – a dry soil will resist penetration more than a wet soil, regardless of soil compaction.

Marking Flags

Marking flags can be used to assess compaction. Insert the wire gently and smoothly until the wire starts to bend. Measuring compaction in several areas across the field may help to identify patterns and possible causes of the compaction.