DIY Field Soil Tests
DIY Field Soil Tests
Ground penetration
A penetrometer is a device to test the hardness of the soil. While you can buy sophisticated ones for hundreds of dollars, you can make your own from a few cents worth of fencing wire as explained below.
- Take a 40 cm length of 3 mm fencing wire.
- Use 15 cm of the length to make a handle, and
- on the remaining 25 cm make file marks every 2 cm from the end.
Source: Tuckombil Landcare Inc
Using the penetrometer
- Push your homemade penetrometer into the soil as deep as you can with modest effort.
- Record the depth of penetration
If you hit a rock or tree root, choose another spot.
The easier it is to penetrate the soil, the better the deep root development and water infiltration.
Infiltration
Infiltration is the rate at which water enters into the soil from the surface. Infiltration is determined by soil texture, changes in soil texture between surface and subsurface, impermeable layers, and depth to bedrock, as well as by soil management. Soil management that improves structure will help to increase water infiltration.
Soil tillage creates an immediate increase in infiltration, but as the growing season progresses, the infiltration rate decreases. In a no-tilled soil, infiltration rates are determined by macropores such as old root channels and earthworm burrows. On an annual basis, infiltration in long-term no-till soils often exceeds that in tilled soils because of the abundance of macropores, but it takes time to build up this pore system.
DIY Test: Infiltration
Tin can infiltration test
- Carefully clear aside vegetation and ground cover.
- Push a tin can (with both ends removed) one to two cm into the soil, avoiding cracks and other holes in the ground.
- Gently fill the can with 500ml of water.
- Time for 60 seconds.
- With a ruler, measure how far the water level has fallen.
A higher rate of infiltration will mean your soil will absorb rainfall more quickly, resulting in less run off and erosion.