The 5th of December 2020 is World Soil Day. Keeping soils healthy is a key aim of our Water Wise Farming programme. An unhealthy soil increases runoff during rainfall carrying nutrients, pesticides and other chemicals into the brooks, streams, and rivers. Even a small amount washed from every field can build up to damage water quality. In severe cases, the actual soil particles can be washed into the river where they can block up the holes between river gravels choking river invertebrates and fish eggs. Keeping soils healthy is vital to keeping the River Dee clean.
A healthy soil is made up of four factors:
- Good soil structure: Well-structured soils, are usually crumbly and friable and have plenty of pore space to allow water and air movement and healthy root development.
- Good soil biology: High numbers of worms and fungi in the soil which help break down and store nutrients in the soil.
- High organic matter levels: A soil consists of broken-down organic animal and plant tissue and broken-down rock. Healthy soil will have a high percentage (3-6%) of organic materials.
- Correct Chemistry: good balance of chemicals and PH.
To help farmers, growers, and landowners care for the soil we offer free soil health assessments. The assessment includes four tests which are undertaken at sites across the farm including all fields under different practices plus a control sample from an un-farmed area, such as beneath a hedge. The control sample allows a comparison with the naturally occurring soil type of the area and the full potential of local soils.
For each location, first, we dig a hole to look at the soil structure. Looking for indicators such as deep protruding roots, round-edged clumps, the ease with which the soil breaks apart and even the smell of the soil can tell a lot about its health. Secondly, we count the number of worms at each site; Worms are a great indicator of soil health, the more the better and healthy soil can have more than 30 worms in 20cm³. Worms numbers vary wildliy for a variety of reasons, such as temperature but a large difference between the control site and sites in the centres of fields would be a concern and indicate soil health may be diminishing.
Heavy farm vehicles and livestock travelling along fields can cause air pockets to collapse, this is called compaction. This has a negative effect on plant growth and water retention within the soil, leading to increased rainfall run-off and erosion. The third test we complete is called a bulk density test, which indicates how compacted the soil has become. A set volume of soil is dried and weighed giving a result expressed in g/cm³ which can then be compared against the control sample.
The final test is a slake test, this involves submerging a dried clump of soil underwater and measuring the speed with which it breaks apart. Healthy soil will contain lots of organic matter and fungi mycelia which will hold the soil together. This makes them more resistant to heavy rainfall and less likely to cause erosion.
Once a soil health assessment is undertaken, the results are returned to the farm. Advice and support are then provided to help the farm make any changes or trial new ideas to help improve soil health that they would like to undertake. This can be using specialist equipment to break up soil compaction, changing the way livestock graze the field or even using specialist plants to root deep within the soil.
The Water Wise Farming Programmes proactive win-win approach of working with farmers is used across all of the projects and is making a real improvement to River Dee catchments soils and water. So we are proud to celebrate World Soils Day 2020 not just on the 5th December but every day of the year.
If you are a farmer or landowner in the River Dee catchment and interested in a soil health assessment of your farm ,then please get in contact using the link at the bottom of the page.
The Welsh Dee Trust is an independent charity which is funded through a variety of sources, but it is donations from our supporters which are most valuable and allow us to carry out work with farmers to improve the health of the River Dee catchments soils and ultimately the health of the River.
If you would like to support our work including our Water Wise Farming Programme, please Donate Today.