Maintaining soil quality supports soil productivity and crop profitability. Soil changes over the rotation are important indicators of how management decisions are impacting soil quality.
Regular soil quality assessments carried out by farmers can assist with:
- Understanding the full impact of prior management decisions.
- Identifying existing constraints to production.
- Selecting and implementing future management strategies that improve soil quality and are feasible for your operation.
- Measuring progress and adjusting management appropriately.
- Providing evidence of good soil management practices to support FEP audits.
The visual soil assessment
This simple soil quality ‘mini’ visual soil assessment (mini VSA) for cropping farmers is adapted from the Soil Quality Management Assessment (SQMS) developed by Plant & Food Research, the Visual Soil Assessment produced by the Soil Management Initiative (UK) and Manaaki Whenua - Landcare Research’s visual soil assessment field guide.
It involves carrying out three quick tests on:
- Structure & porosity
- Turbidity
- Earthworms
A good soil structure provides greater resistance to compaction and maintains the necessary soil porosity for roots to access air, water and nutrients. The structure & porosity score along with the turbidity score assess the structure and stability of soil aggregates.
Earthworms are an important biological indicator. Through their feeding and burrowing activities, earthworms can enhance nutrient availability, increase the infiltration and movement of air and water, and improve the structural condition and stability of soils.
Scores for each test are recorded on a score sheet. They are likely to fluctuate as the rotation transitions through depletive and restorative phases, but they will allow overall trends to be tracked over time.