Choose one of the two following methods.

1. Infiltration rate

Importance

Infiltration rate or infiltration capacity is a good indicator of physical soil quality since it reflects the hydrodynamic aspect of soil structure. Infiltration capacity is defined as the maximum rate at which water soaks into or is absorbed by the soil through the soil surface. There are several devices and approaches to assess infiltration capacity in soils. Here, we propose the method developed at the University of Bern (Switzerland), which was calibrated to assess soil damage due compaction.

Assessment

• Introduce the metal tube carefully into the soil to a depth of 20 cm using a rubber hammer. Do not disturb soil with horizontal movements while introducing the tube.
• Take out the metal tube by turning it slightly.
• Introduce the penetrometer carefully into the soil to a depth of 20 cm (without using the rubber hammer).
• Fill the Plexiglas tube with water (370 mL). Start to record time immediately. After 20 minutes record the volume of water infiltrated into the soil by measuring the height of the infiltrated water (1 cm = 7.1429 ml).
• Conduct at least 3 measurements (within a radius of 0.50 m) to characterize one plot (one control).

Experimental set up

Scoring

Good condition: Score 2

Water volume > 50 mL

Moderate condition: Score 1

30 mL<Water volume>50 mL

Poor condition: Score 0

Water volume < 30 mL

2. Penetration resistance

Importance

Penetration resistance (PR) is correlated with root growth, earthworm activity, and tillage effects. When PR exceeds 2 MPa, root growth is often reduced by half, while values > 3 MPa often prevent root growth. Tillage may increase the critical stress value of a hard-pan to > 3.5 MPa depending on the nature of the pore system and the type of soil structure.

Assessment

In each plot, PR should be measured at least 10 times within a radius of 0.50m down to a depth of 0.40 m. Measurements should be made with a cone with a cross-sectional area of 1 cm². The cone should be pushed slowly and regularly into the soil. The depth and the force resolutions are 0.01m and 1 N respectively (see manual below for more explanation). The vertical measurements have to be averaged for each depth layer and the measurements of the plot_AMP and these of the control have to be statistically compared.

Penetrometer

Scoring

Good condition: Score 2

< 2 MPa

Moderate condition: Score 1

2– 3 MPa

Poor condition: Score 0

> 3 MPa

References:

https://en.eijkelkamp.com/products/field-measurement-equipment/penetrologger-set-a.html