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Why Soil Matters

Why Soil Matters

Picture: Philip Bews of Gorn Farm, Westray, Orkney

An Orkney farmer says the results of changes he made to his farm following one of our soil health events have been “stunning”.

Philip Bews, who runs a 630-acre mixed farm on Westray, says he now uses 20% less fertiliser, and has been able to keep 20 more yearling calves on his farm (almost 12% of his herd) since attending the event in June 2016.

“I learned about the need for aeration,” says Philip. “After the event we purchased a flat lifter and the results have been stunning for grassland and barley: it’s been amazing! I used it on bits of fields and you could see the line between where I’d used it and where I hadn’t by the grass.”

At our events, we ask people to bring in a spadeful of their poorest soil for physical assessment. “You can’t figure out how to improve your soil until you know what you’ve got,” says our Farming and Land Use Manager, Lyn White. “Soil is a farmer’s biggest asset. Every farm has it, it is the biggest influence on production and yield, and it’s not that expensive to get it analysed.”

Picture: Liz Stockdale gets her hands dirty at a soil health event

Our invited experts, such as GrassMaster Charlie Morgan and Liz Stockdale of the NIAB, investigate what is growing on top then look for clues inside the divet, such as smell, colour and root depth (see tips below).

“I took along my soil sample,” says Philip, “and when the expert broke it up, it split horizontally – I didn’t know that was a classic sign of compaction. He advised buying a flat lifter to aerate the soil.

“Since then the increased grass has meant we can reduce our use of fertiliser – we bought 20% less last summer. That’s a win win -  we’ve saved money on that and the freight costs, which are high here, and although we’re not an organic farm we try to apply organic principles where we can because it’s better for the environment and the soil – if we can use less fertiliser we are happy.”

“If the soil’s not right, the livestock aren’t right,” he adds, and indeed his improved grass has meant he can keep more cattle. “Because of the increased grass growth, of the calves born last Spring I’ve kept 20 more than I otherwise would have.”

He also learned how to look at soil life – such as the worm count-  to judge soil health. “Now I know how many worms to expect in a clod [around 25 per cubic foot] I’ll dig up some soil, count them and look at root structure.

"I'll be coming to your next soil event, hoping for more information.”

Picture: A healthy-looking worm

Lyn’s top tips on how to assess your soil:

1/ Dig a hole

Dig a hole in a field or part of a field that’s under-performing, and bring out a spadeful of soil. Pull it apart with your hands, looking out for:

Compaction. If the soil is very solid, like concrete, and breaks into big bits rather than crumbling, it doesn’t have enough air in it. This can be due to machinery, poaching, or too much rain weighing it down. Soil is a living thing, it needs to breathe. If soil is compacted you could consider using a sward lifter (flat lifter) or aerator.

Smell. Soil should smell earthy. If it smells eggy, or rank, it’s another indication that it doesn’t have enough air in it.

Colour. If it looks grey, with red or orange mottling, it’s another sign of poor drainage.

2/ Know your alphabet: pH, P and K

It’s best to send a sample of your soil to a lab to check its chemistry. If it’s much too acidic (below pH6) then you’ll need to apply some lime. Grass and crops grown in very acidic soils won’t yield well, no matter how much fertiliser you throw at them. You’re also looking for moderate levels of phosphate (P) and potassium (K).

3/ Count the worms

Biology is important – you should have as much microbial activity in the first six inches of soil as livestock supported above it. There should be around 25 earthworms per cubic foot and you shouldn’t have to dig too deep to find them. There should be a variety of different kinds, shapes and sizes, of a deep, healthy colour, and they should be actively wriggling about. No worms could mean compacted soils, or too low a pH.

Check out our DIY guide Healthy Grassland Soils.