Introduction

Introduction to Break New Ground Project

Good practice in wildflower landscaping has shown that seed establishment occurs best on low fertility substrates (Flowers in the Grass, English Nature (1992), Wildflowers Work, Landlife (1995)). Creative conservation project work, by Landlife on a large scale, has further demonstrated the advantages of utilising low fertility substrates. soil inversion would give woodland wildflowers an opportunity to develop in situations where high fertility would otherwise be a problem, and it may provide a solution to enable the parallel establishment of woodland flora with new tree plantings. Wildflowers benefit both from reduced competition by aggressive and dominating species and from a reduced seed bank of weedy species. In the long term this would help to establish a landscape rich in biodiversity rather than a simplified landscape of trees with grass. Landlife was invited to submit an article for the June issue of Landscape Design (print run 6,500 readership estimated 20,000 plus), which highlighted our creative conservation philosophy and announced the Break New Ground project.

Top soil stripping a precursor to soil inversion

Creative conservation landscapes advocated by Landlife are established using a simple matrix of species allowing nature to mould the final result, with an appropriate level of management. This has been most successfully demonstrated at the 1.7 hectare soil stripping site in Huyton using simple combinations of key common species on a low fertility substrate. The landscape was sown with a total of 16 species in 1993, and in 2000 it was recorded as having a total of 57 in the space of six years.

Theory underlying soil inversion

By exposing the underlying subsoil, through soil inversion, wildflower species can be sown directly into the substrate in the same manner as soil stripping. The soil will be inverted by deep ploughing to bring the soil to the surface exposing the clean and weed free substrate, to enable a companion trees and flowers approach.

The advantages of the soil inversion technique the project seeks to demonstrate are:-

• The existing seed bank in the soil is buried, bringing a weed free subsoil to the surface.
• Reduced fertility and weed growth in the soil should result in reduced weed competition and hence reduce the need for herbicide and management costs in the tree establishment phase.
• Trees will be rooting into the soil at a lower horizon, so can access the nutrients and moisture available from the now upturned soil, with the buried humus layer.
  
• Wildflower species can be introduced with the advantage of reduced competition on a low fertility substrate.
• By the time the canopy has established and light stress comes into play, the basic components of a simple and attractive woodland flora should be flourishing.
• The soil resource is retained on site.
• An open sward, with some bare ground encourages invertebrate populations.

Additional implications

At the time of ground disturbance there will be an initial flush of nutrients, due to the mechanical disturbance of the soil, and an impact on soil micro fauna and flora. There may also be a problem with soil erosion due to areas remaining free from vegetation for long periods. This will be overcome by sowing wildflower seed mixes onto the bare subsoil. Seed provenance must also be considered and Landlife will advocate the use of seeds from local sources to supplement the sowing of common UK species. Damage to archaeology due to the depth of ploughing must also be considered. A full archaeological survey must be carried out before the ploughing is done.

Pilot projects

Pilot projects to demonstrate this technique are being initially jointly undertaken by Landlife, the Woodland Trust and the National Forest. The selection of potential areas will target soils that are most amenable to this technique. Monitoring will be an important part of the soil inversion pilot projects in order to test crucial aspects of the hypothesis. Essential funding by the Esmee Fairbairn Foundation has facilitated the Woodland Wildflowers Project. The project is managed by Landlife and involves all twelve of the Community Forests. Its objectives are to create a collection of keynote woodland flora species, for future creative conservation initiatives, and to improve the diversity of sites within each Community Forest through a sowing regime using appropriate wildflower species. Some of the sites selected by the Community Forests will have the topsoil removed, exposing the subsoil, on to which the wildflower seed will be sown. Research data from the Woodland Wildflower project will be used to enhance the results from the soil inversion pilot projects.

Following further research we were able to ascertain the practical possibilities of finding a plough capable of inverting the soil profile. The World Ploughing Organisation - an organisation which organises the annual World ploughing championships, and aims to progress good practice in ploughing- was able to locate a plough manufacturer in Denmark, who had long term experience of building and supplying ploughs of this type. Deep ploughing in fact had been a traditional means of dealing with weed control in Danish forestry, and we were able to source direct recent experience from both the Danish Forest and Landscape Institute and a special project where deep ploughs were being used in Lithuania. A paper titled the Novelty of Something Forgotten (Gediminas Survila, 2000) highlighted the success of this technique in Lithuania, and reinforced many of our own assertions.

Subsequent contact with key Danish researchers concerning our own hypothesis confirmed our hopes, and even though the Danish work had only been concerned with the reduction of weed control it became clear that the opportunity for combined wildflower and tree planting was a primary bonus.