There are different aspects of soils that can be measured to provide useful information.
Soil fertility and pH
It is vital to carry out an assessment of soil fertility before attempting to restore or create a species-rich floodplain meadow, as this will determine whether or not it is feasible. Floodplain meadows require soils that have moderate levels of soil nutrients, particularly phosphorus (P). Soils should be analysed for extractable phosphorus, potassium (K) and magnesium (Mg).
Soil pH should also be measured, as sites that are too acidic (pH < 5.5) are unsuitable for species rich floodplain meadows.
Understanding how much P is deposited in floods will help understand whether there is too much arriving on your site from the wider catchment. The collection of flood sediment in the field can be done by putting out sedimats over winter to collect sediment if the field floods, and then analysing these for P, K, Mg and pH in the lab.
Soil structure
Knowing whether the site has good soil structure or is compacted is really important. Compacted soil will severely limit the potential of the site to be more species rich, and can take many years to remediate. Soil structure and compaction can be assessed by:
- Look at soil structure and profile by using a 50mm Dutch Auger to extract a core up to 1 m deep. Describe the soil type and structure every 10 cm.
- Looking at soil structure by lifting a spit with a spade. Compaction caused by stock is typically seen in the top 25cm.
- Compaction is more accurately assessed by digging a full soil pit or carrying out bulk density assessments. These involve collecting soil cores and drying them in on oven to record dry weight. This would only be advised if lifting a spit shows evidence of compaction.
