| Physical Properties |
Optimal range |
Effect |
| Moisture (%) |
35 - 55 |
Higher moisture, increased handling and transportation costs |
| Organic matter (%) |
50 or more |
Higher organic matter lowers application rate |
| pH |
5.0 - 8.0 |
In acidic soil, alkaline compost will raise pH |
| Water holding capacity (WHC) (%) |
20 - 60 |
Higher WHC leads to lower irrigation frequency |
| Soluble salts (dS@m-1) |
less than 6.0 |
Higher than 6.0 means potential toxicity |
| Bulk density (lb/cu yd fresh weight) |
500 - 1000 |
Higher moisture content means a greater bulk density |
| Particle size |
Passes 1 inch screen |
Increase soil porosity |
| C:N ratio |
15 - 25:1 |
Higher C:N ratio causes "N-immobilization" |
| Maturity (G.I.y) |
Over 60 |
GI lower than 60 indicates phytotoxicity |
| Compost stability |
Stable |
Instability can cause "N-immobilization" |
| Weed seeds |
None |
Uncomposted materials disseminate weeds |
