Assessing soil health and function Revision as of 17:06, 24 June 2021 by Mtrojan (talk | contribs) (→Ability to support vegetative growth)
Soil health is an assessment of how well soil performs all of its functions now and how those functions are being preserved for future use. The assessment of soil health depends on the desired functions of the soil. In agricultural applications, for example, soil health is determined by assessing properties that affect plant growth, such nutrient status, pH, and bulk density.
For stormwater applications, soil health can be assessed for the following functions.
- Ability to support vegetative growth
- Fully functioning soil ecology
- Supporting hydraulic/hydrologic function
- Ability to minimize erosion
Each of these is discussed below.
Ability to support vegetative growth
The following indicators can be used to assess suitability of a soil to support plant/vegetative growth.
- Soil compaction (bulk density): Soil compaction results from repeated traffic, generally from machinery, or repeated tillage at the same depth, which results in a compacted layer at the tillage depth. Compaction inhibits infiltration, gas and water movement, may impede root growth, disrupts habitat for soil biota, and affects nutrient cycling.
While there are established relationships between acceptable levels of compaction and plant response, bulk density is often used as the indicator for degree of compaction. Relationships of bulk density to root growth are shown in the adjacent table. See methods for measuring and methods for measuring compaction. See Soil physical properties and processes for discussion of bulk density.
General relationship of soil bulk density to root growth based on soil texture
Link to this table
| Soil texture | Ideal bulk densities (g/cm3) | Bulk densities that may affect plantgrowth (g/cm3) | Bulk densities that restrict root growth (g/cm3) |
|---|---|---|---|
| sands, loamy sands | <1.60 | 1.69 | >1.80 |
| sandy loams, loams | <1.40 | 1.63 | >1.80 |
| sandy clay loams, loams, clay loams | <1.40 | 1.60 | >1.75 |
| silts, silt loams | <1.30 | 1.60 | >1.75 |
| silt loams, silty clay loams | <1.40 | 1.55 | >1.65 |
| sandy clays, silty clays, clay loams with 35-45% clay | <1.10 | 1.49 | >1.58 |
| clays (>45% clay) | <1.10 | 1.39 | >1.47 |