Soil stabilisation

Please refer to final report below.

The Problem:

With up to 28 weeks storage required under the proposed revisions to the NVZ action programme measures, and the extension of the designed areas (from 55% to 68% of England), many livestock farmers will find themselves in need of additional slurry storage with the next two years.  On heavier soils the construction of earth-banked lagoons to CIRIS/SSAFO standards is by far the most cost-effective approach to the storage of whole slurry.  In chalk and sandy areas, where farmers have traditionally spread manures through much of the season, achieving the standards is much more difficult, and the alternative options of concrete or steel stores are significantly more expensive.  Artificial liners, whilst more cost effective, are less resilient than earth-banked stores, and are generally better suited to very low DM material and dirty water.

Soil stabilisation techniques (the use of lime and cement powder and other materials mixed with native site materials in-situ and consolidated) have advanced significantly, and appear to offer a low cost approach to significantly enhancing both the impermeability and bearing capacity of sub soils in light land areas.

Project Aims:

1. To assess the potential of an existing technique for road construction for the stabilisation of highly permeable soils and subsoils for slurry and effluent storage
2. To assess the optimum design criteria for the technique when used for slurry storage on permeable soils
3. To demonstrate the suitability of the approach for slurry storage and capability of achieving the required construction standards for impermeability
4. To confirm the suitability of the approach for a follow-on assessment at the field scale, via construction and monitoring of a storage lagoon on a suitable farm site.

Approach:

The technique will be trialled on a bench scale, with experiments on rate of inclusion and a range of particle sizes/moisture contents will be conducted on cores of sandy and chalk/shallow limestone soils.  Cores will also be taken and tested from sites where the technique has been used for the construction of farm/forestry tracks.

Deliverables:

The results will be used to advise livestock producers about their options for increasing slurry storage.