| Indicator |
Time to test |
Healthy Condition |
| Earthworm presence |
When soil is moist |
>10 worms/ft3 castings in tilled clods |
| Color |
When soil is moist |
Topsoil remains darker than subsoil |
| Presence of plant residues |
Anytime |
Residue on most of soil surface |
| Conditions of plant roots |
Late spring or during rapid growth |
Roots extensively branched, white, extended into subsoil |
| Degree of subsurface compaction |
Before tillage or after harvest |
A stiff wire goes in easily to 2x plow depth |
| Soil tilth or friability |
When soil is moist |
Soil crumbles easily |
| Signs of erosion |
After heavy rainfall |
No gullies, runoff from field clear |
| Water holding capacity |
After rainfall during growing season |
Soil holds moisture at least a week w/o signs of drought stress |
| Water infiltration |
After rainfall |
Norunoff; soil surface does not remain excessively wet |
| pH |
Same time each year |
Near neutral and appropriate for crop |
| Nutrient holding capacity |
Similar time of each year |
N, P, and K stable and sufficient content |
