Soils

Soils are an incredibly valuable resource, their conservation and enhancement is critical to achieving healthy landscapes. Soil type determines; pH (how acid or alkaline), how quickly or slowly water drains away and the amount of nutrients the land naturally contains. In turn, these factors help to determine species composition – the different types of grass, herb and flower species that might grow well in particular soils.

Soil and the species it sustains, directly influence the capacity of grassland to support grazing animals, including horses. Soil type and species also affect how these grasslands might be managed.

The South Downs National Park comprises many different landscapes, whose different characters result, in part from a wide variety of soils. These soils in turn support varied (grassland) habitats and species contributing towards the landscape’s distinctive character.

Soil Facts

All soil types have the ability to be wonderfully species-rich.
Chalk soils tend to be very thin and free-draining. These soils are therefore less likely to hold on to nutrients and are often of low fertility. Grasslands on chalk can be very species-rich. They are usually alkaline, but can be capped with clay in some places.
Clay soils are often heavy and can become waterlogged and quickly damaged (poached) by livestock and horses in wet conditions. These soils hold nutrients and therefore that tend to be more naturally fertile. This means clay soils usually support fewer species than chalk. They can have a varied pH.
Sandy soils can be free-draining. They can therefore also be low fertility, with potential to support a diverse group of plants. Sandy soils are likely to be more acidic.
Many soils in the South Downs National Park are complex and could display a mixture of these properties over a relatively small area.
Regular poaching by livestock and horses causes damage to the soil structure (compaction), erosion, and encourages weed species such as docks, ragwort and thistle to become established.
Damaged soils may lead to horse health problems such as mud fever.

It is possible to do a quick and easy assessment of your soil type by using the following resources:

Soilscapes: Provides the likely soil type, useful for getting to know a site in its landscape context. This is general information – not specific enough for an individual site, but will give a good start.
Soil Testing: To find out more about land that is used for grazing horses, this method of soil sampling can be used. It can be sent away for analysis at a cost of around £20-£30. Testing for key nutrients; Potassium (K), Phosphorous (P) and Nitrogen (N) is important evidence to help determine appropriate species choices and management for your grassland.
Most soil testing is still undertaken with productivity in mind, so treat with care any advice that suggests manipulating characteristics of soil, such as altering pH. Overtime, this could change the ability of the land to support characteristic species and ultimately change the character of the land, which is so important to the National Park’s designation.
Soil Management: Healthy soils are the foundation of healthy pasture and livestock – find out more here about how to care for soils.
Think Soils: An Environment Agency Manual for all land managers.
Agriculture and Horticulture Development Board produce guidance for collecting soil samples and links to information and advice about soil health.

Soil type can vary across a holding so different fields may need a different (bespoke or landscape-led) approach to management, for example be grazed at different times of the year.

Observing and getting to know the land enables a reactive management approach in response to conditions – this can greatly reduce damage to at-risk ground and help to conserve the landscape.