Five Top Tips: Tackling Rushes
David Michie from Soil Association Scotland shares some top tips on tackling common rush on your farm, based on findings from the team’s recent field lab.
Across the past 18 months we’ve been working with farmers and crofters across Scotland to find the best ways to manage Juncus effusus, known as soft or common rush. Rushes are a growing problem all over Scotland and elsewhere in the UK: they seem to be getting worse as the weather gets wetter, and they can easily take over grass fields, reducing the amount of good grazing.
So, to help you win the battle with rushes on your own farm, here are my top five tips on rush management.
Tip 1: Get your drainage right
Good drainage is fundamentally important. If your soil doesn’t drain, then the next four tips won’t work as well for you.
When it’s reasonably dry out, get your spade and dig a hole. If it’s full of water, or if there is gleying (greyish blue soil with red or orange flecks), then your soil might need to be drained better.
Installing or fixing drains can be expensive, so start with the cheapest solution: clearing outfalls. If you need to hire a digger to replace, install or re-install drains, costs can start escalating. Is it worth draining wet field corners or poorer fields? It could be more costly than any benefit you’ll get, so weigh it up carefully.
Tip 2: Give your soil room to breathe
Compacted soil makes it difficult for roots to reach nutrients, and also makes drainage more difficult – all of which makes a perfect environment for rushes.
Is your soil compacted at all? If it isn’t, no need to do anything about it, move on to tip 3; fixing compaction has a cost, so don’t jump in before you know if it’s an issue for you.
But if it is, which bit is compacted? Deep down in the subsoil, or higher up in the topsoil? Subsoil compaction can be addressed with a subsoiler, but it’s expensive, so only use it if you really need to. If you have topsoil compaction, assess how bad it is. Use a sward lifter for very compacted topsoil, and a sward slitter or aerator for lesser compaction nearer the surface.
Tip 3: Don’t ignore the science bit
Correct soil sampling and analysis is absolutely essential if you want to win the fight with rushes.
A routine soil analysis result will give you the soil pH, as well as its phosphate (P), potash (K), and magnesium (Mg) status. Getting all these things right will favour the growth of more productive grasses and clover – letting them compete with the rushes.
Different soils have different target pHs, but a mineral soil in permanent pasture here in Scotland should be limed to pH 5.8 or above. As for P and K, the status of your soil should show at least as ‘Moderate’. If your soil analysis comes back as ‘Low’ for P or K, use livestock manure applications, or apply supplementary nutrients.
Tip 4: Get cutting
Cutting at the right time is a crucial part of managing rushes, as it can prevent the plants setting seed. It can also let light into the sward, making grass and clover more competitive, and make lime and nutrient applications much easier.
If you have a lot of rushes it’s worth considering if you want to bale and remove the cut rushes, so you can use them for livestock bedding. Beware of doing this with rush plants that have set seed, though – you may end up spreading rush seed to ‘clean’ fields when you spread muck.
Tip 5: Get ready for a reseed
Don’t be tempted to jump straight to this stage – we found that reseeding without sorting everything else out first is likely to lead to failure.
But if you’ve got the previous four steps right, you can explore what the best reseeding method is for your field. Consider giving the existing sward a good harrow beforehand for an increased chance of success.
Make sure you have a good chat to your seed merchant about the best seed mix for your field too: we found that very productive ‘off the shelf’ seed mixes can have species in it that are likely to die out on marginal land prone to rushes – letting the rushes get back in and making the problem worse. Go for a more persistent mix that’s likely to compete with the rushes.
So really the secret to managing rushes sustainably is an old favourite: good grassland management. Rushes can be controlled, provided you are willing to invest a bit of time and money; given the cost that can be involved, prioritise your best fields, so you get the best return on your investment.
In some cases it just won’t be worth getting rid of the rushes, and in that case, the key is learning to live with them and make them work for you. They do have some benefits – as shelter for lambs, and as habitat for wading birds – so why not put them in an agri-environment scheme (like AECS here in Scotland) and get some income from them?
Whatever you decide, get the spade out, and good luck!