Understanding A Site

When presented with a field, working out whether or not it is suitable and coming up with a design can be challenging for a newcomer like myself. So I thought I would share the tools and resources that helped me go through the process.

Finding out about the soil

There are lots of basic tools and tests out there to help you get a sense of the nature of the soil you are working with. Ranging from; basic ‘soil modelling’ or letting a sample settle out after being shaken in solution to help determine texture, looking at rates of water infiltration, basic DIY pH testing kits, looking at health and types of vegetation growing on the site, and digging holes to look at profiles and depths. Plenty of guidance out there online. https://www.agricology.co.uk/resources/know-your-soils-8-3-key-soil-tests-understand-your-soil-health

But it can be helpful to get some other information about likely soil qualities of a site. I have used the website Landis (http://www.landis.org.uk/sitereporter/index.cfm), which can produce reports about soil in any location across the UK. Reports are free for undergraduates or those with a ‘.ac.uk’ email if not it only costs £6 to get a basic report. LandIS, the “Land Information System”, is a substantial environmental information system operated by Cranfield University, UK, designed to contain soil and soil-related information for England and Wales including spatial mapping of soils at a variety of scales, as well as corresponding soil property and agro-climatological data. The Soils Site Reporter creates in-depth soils reports for any site in England and Wales. Soil attributes and descriptions, including their vertical profiles, can also be included. Based on the selected region, a PDF document is created for downloading and printing.

I created a basic report for the proposed walnut field to get a sense of the geology/soil types to access if they were likely to be suitable. The report seemed to suggest the soil type would be suitable. The information in the ‘basic undergraduate report’ included:

• Hydrology of Soil Type (HOST) (The Hydrology of Soil Types (HOST) classification describes the pathways of water movement through the soil)
  • Proposed walnut site: “Class 3: Free draining permeable soils on soft sandstone substrates with relatively high permeability and high storage capacity”.
• Soil Parent Material– The underlying geology or ‘parent material’ has a very strong influence on the development of the soils of England and Wales.
  • Proposed walnut site: “Type 133: Permian and Carboniferous reddish breccia”.
• Natural Soil Fertility
  • Proposed walnut site: “Class 5: Low. Soils identified as of low natural fertility are usually acid in reaction and are associated with a wide range of habitat types”.
• Simple Topsoil Texture. Soil texture describes the physical composition of the soil in terms of the size of mineral particles in the soil (proportions of sand, silt and clay).
  • Proposed walnut site: “Type 2: Loamy- Loamy soils have a mix of sand, silt and clay-sized particles and are intermediate in character”
• Typical Habitats: There is a close relationship between vegetation and the underlying soil.
  • Proposed walnut site: “Neutral and acid pastures and deciduous woodlands; acid communities such as bracken and gorse in the uplands”
• Hydrogeological Rock Type: The hydrogeological classification of the soil parent materials.
  • Proposed walnut site: “Soft bedded sandstone or weakly consolidated sands”

• Ground Water Protection Policy: The Ground Water Protection Policy classes describe the leaching potential of pollutants through the soil.
  • Proposed walnut site: “Soils of intermediate leaching potential which have a moderate ability to attenuate a wide range of diffuse source pollutants”
• General description of soil at proposed walnut site: “CREDITON 541e Well drained gritty reddish loamy soils over breccia, locally less stony. The major landuse on this association is defined as Dairying and stock rearing; cereals and roots: some horticultural crops”
• Soil Profile:

Lab soil testing

I wanted to get a baseline soil test done by a lab to find out some more detail about the soil I was planting in to. There are plenty of different labs offering different style soil tests out there. I decided to try two different tests; I got a ‘broadspectrum’ analysis done by Hill Court Farm Research Ltd and a ‘soil health’ analysis done by NMR laboratories. The results I got back were as follows:

What does it all mean? Well it is interesting I got two very different pH’s (5.8 vs 6.4 which is significant on a logarithmic scale) the later suggests soil is within desired 6-7 pH range whilst the first suggests the soil is slightly more acidic than is optimal. Also differences in the levels of K and Mg between samples but both within desired range. The soil samples I send were from the same bucket containing well mixed soil collected from 25 random sites across the whole field. Walnuts would tolerate both pH’s so I am not especially concerned, just curious about the irregularity. The soil health profile from NMR- suggests the soil and site is well suited to the trees- with the ideal loamy texture and in ‘good health’. Hill Court Farm suggest the soil could be deficient in Sulphur, Molybdeum, Sodium and have a low Cation-Exchange-Capacity (CEC) (low ability to hold and release positively charged minerals and nutrients). This information could be useful down the line if the trees look like they are showing nutrient deficiencies. Whether having the soil tests done is particularly useful in the short term is debatable, but it is always interesting to have more information and it might be useful for reference in the future.

Researching and mapping a site

I like to use DEFRA Magic Maps (https://magic.defra.gov.uk/) to find out about land use/restrictions and for basic mapping and measuring.

The MAGIC website provides authoritative geographic information about the natural environment from across government. The information covers rural, urban, coastal and marine environments across Great Britain. It is presented in an interactive map which can be explored using various mapping tools that are included.  More than 300 data layers are available on MAGIC. The MAGIC partnership organisations are Natural England, Defra, Environment Agency, Historic England, Forestry Commission and Marine Management Organisation.

You can select a site by defining an area or placing a point on a map, then see any environmental or agricultural data entered for that site. This includes existing subsidy claims (e.g. BFP or higher level stewardship), habitat classifications or environmental protections (e.g. SSSI’s or protecting species in that area). There are good tools for measuring distance and area. Maps can be visible as OS, aerial satellite or base map.

Measurements of field using magic maps

Other information about site I could find out from Magic maps:

• Field currently entered under: COUNTRYSIDE STEWARDSHIP (Middle Tier) Higher Level Stewardship.
• Field is in a ‘Nitrate Vulnerable Zone’
• Field is in an area under protection for ‘Priority Species for CS Targeting – Brown Hairstreak butterfly’
• Field has a ‘Aquifer Designation of Typology Secondary A’ and a ‘Groundwater Vulnerability classification of MINOR_I’
• Field has the following soilscape: “FREELY DRAINING SLIGHTLY ACID LOAMY SOILS. NEUTRAL AND ACID PASTURES AND DECIDUOUS WOODLANDS; ACID COMMUNITIES SUCH AS BRACKEN AND GORSE IN THE UPLANDS. ARABLE AND GRASSLAND”

Finding out the contours for a site

It can be helpful when doing a design to see a contour map of the site. I recently discovered this website and have found it very useful.

Contour Map Generator: https://www.contourmapgenerator.com/#2/37.9/-44.6

This contour map generator is a feature of The Adaptive Habitat Program, hosted by Verge Permaculture.

Here are the contour maps I was able to generate of the proposed field using the website:

Coming up with a design…

Features to include in design:

• 90 walnut trees spaced on a 12m grid.

Factors I considered when drawing together layout

• Slope and contour of land
  • Access
  • Existing fence lines
  • Ease of marking out
  • Exposure of site
  • Situation to near by copse.

I decided to plot a grid- running parallel to western side and top fence line. This was partly for ease of marking out as you have reference points to follow but also should mean tractor work can occur directly across and down slope. One slight downside with this layout could be that space is lost on the lower part of the slope- which is likely to have deeper soils and suffer from less wind exposure (but may also be a frost pocket- so perhaps no bad thing).

I made the western field side edge 125m using Magic maps ruler. Starting the rows 5.5m in from the western edge- I hoped would leave sufficient access to that fence line. This enabled a wider edge on the eastern side where there is an isolated pocket of existing woodland (useful to have a grass buffer as extra squirrel deterrence).

I had a go at plotting a 12m grid on the field (with 90 trees planted on intersects), simply using ‘Microsoft Word’. The grid is started 24m of the top edge of field, leaving 17m off the bottom edge.