Weather records show that winter rainfall is increasing in Scotland. These rainfall events are becoming more intense and often localised. Climate change predictions suggest that this trend will continue, with both the amount of rainfall and number of wet days increasing1
What measures at the field level could we consider now, that could reduce the impact on the business following heavy rainfall events in the future? Here are some ideas:
Protecting the soil surface
Keeping the soil covered protects the soil surface from erosion by heavy rain and wind. There are a number of ways this can be achieved, including creating a mat of dead plant material from crop residue such as straw, or by sowing a cover crop to protect the soil. The cover crops provide protection for the soil surface, acting as a shield and enriching the soil. Depending on the mix, cover crops can bring other benefits too, for example helping to improve soil structure and break up compaction.
Compacted soils will impede free drainage through the soil profile. This can waterlog roots and submerge crops, keeping more water locked in the upper profile of the soil surface. Compacted soils can also increase flooding risk, reducing the ability to hold additional water. The visual evaluation of soil structure (VESS) guide can help you assess soil structure. Reducing waterlogging through addressing soil compaction could also benefit yields and improve access to the field.
Reducing run off
Alongside protecting farm soils, buffer strips around watercourses can slow the flow of water over land and the vegetation can trap sediment particles, reducing runoff into the burn and reducing the amount of sediment that could contribute to blocking the watercourse. Other techniques, such as sediment traps and bunds can also help to reduce runoff and soil loss from the farm. To us it’s just muddy water, to wildlife sediment can be lethal.
Field drains can silt up and block, preventing water getting away and backing up. Check field drains are running. Field drain outfalls should have a reasonable clearance between the outfall and normal water levels in the receiving ditch or burn. Erosion around the pipe end can cause soils to slump and cover the drain outlet, making it harder to locate. Clear, clean and repair pipe outfalls; mark pipe outlets so that they can be easily identified in future (e.g., a painted post on the ditch bank).
Is water flowing, or is flow being restricted by sediment or vegetation? If maintenance is required, clear sections of the ditch on a regular basis – no permission is needed to maintain man-made ditches under 1m in width, just compliance with good practice as outlined in the Controlled Activities Regulations guide. The aim is to remove accumulated vegetation and sediment which is impeding flow only, not to further deepen the ditch. Some works will need authorisation from SEPA, so it would be worth contacting your local SEPA office to discuss beforehand.
New field drains
Maintaining ditches can also avoid more costly extra field drainage. However, with increased frequency of wet weather, do you need to consider adding new field drains? If you are planning new field drains, it would be worth getting a full drainage plan done with a view to completing it in sections if you don’t want to fund it all in one go.
Farmers have always worked with the weather, but it seems our changeable and more extreme weather patterns will continue. There is no one-size-fits-all approach, but there are a range of actions you could consider to improve the resilience of your farm business in the face of our changing climate.
What next and where to get more information
- Take a look at some of the ideas from Soil Regenerative Agriculture Could you integrate some regen ag principles into routine activities?
- Read the Valuing Your Soils Brochure for a refresher on all things farm soils, with examples of what other farmers have done to protect and improve farm soils.
- Carry out a VESS in problem areas on the farm; do you have areas of compaction that need to be rectified?
- Check soil infiltration rate – see our Practical Guide
- Take a walk around farm ditches – are they clear? Farming and Water Scotland offer more information about field ditches and dredging. The practical guide to the Controlled Activities Regulations provides additional detail.
- Check field drains – are they well maintained and free flowing?
- Could a new drainage scheme benefit the farm? These FAS Technical notes talk through how to assess the requirement for drainage and planning for agricultural drainage.
- There’s more information on Natural Flood Management techniques over on the Farming and Water Scotland pages, including the SRUC booklet Natural Flood Management; A Farmers Guide
- For more information on how farms in Scotland could adapt to a changing climate, take a look at our adaptation pages.