How to plan grazing to avoid soil compaction in wet weather

Preventing soil compaction is cheaper than rectifying damage caused by grazing in wet conditions or overstocking at turnout.

Short term, it is more important to prioritise soil condition over cow performance to avoid compaction, which can affect grass growth for the rest of the year.  

See also: Managing soils to withstand wet winters and dry summers

The key is to be flexible and take steps to avoid making things worse, says independent soils and grassland consultant Chris Duller.

With many soils wet and at water-holding capacity, he stresses the importance of avoiding further poaching and creating new soil damage – particularly when more rain is forecast.

Chris Duller © Hayley Chapman

Have a plan

Grazing causes surface compaction in the top 7-10cm of soil, and while Chris says that most poaching recovers on its own within two months, “footprints inside footprints is a problem”.

He points out that soil damage is compounded when there is no “plan B” for early intervention.

The starting point, he says, is to assess current conditions and compare these with previous wet/dry/average years on the farm.

Poaching damage © MAG/Shirley Macmillan

“Record your wetter and drier fields – for turnout – dig a hole and score them on compaction.”

Using the AHDB system where score 1 is good and 5 is poor, Chris says that a field with a soil compaction score 2 can recover on its own.

Anything at score 3 needs managing differently, and score 4 probably requires mechanical help.

“Compaction from last autumn needs to be identified now, so that those paddocks can be managed differently – this means on/off grazing or back fencing,” he adds.

Back fence

Grazing platforms should be set up with the correct infrastructure to cope with wet conditions.

This means tracks and troughs in the right place, and multiple entry and exit points in each paddock, he says. Good communication among the farm team is essential for this to work.

“Ideally, have single-grazing paddocks where cows are in and out. If you have to graze one paddock over four days, cows are continually in and out, so this is where a back fence works well.”

He acknowledges that back fencing can be a hassle, but says it is a job that pays back, as 20 minutes of work will prevent soil damage that can last 12 months. It may even be as simple as fencing off a wet corner.

© MAG/Shirley Macmillan

Graze lower covers

Being flexible with grazing covers also helps. Very high covers at turnout need a high stocking rate for efficiency.

In such cases, Chris suggests splitting the herd into smaller groups and to keep cows moving round the platform.

“It is a pain, but it reduces damage and it’s just for a few weeks,” he points out.

Instead of sticking to the regular entry cover of 2,800kg/ha of dry matter (DM) and leaving a residual of 1,600kg DM/ha, it benefits soils to “go in lower and come out higher”, he says.

“You might lose a little bit of yield, but it’s not major. Apply a few regen principles by lengthening the rotation round to 40 days instead of 25,” he adds.

Outwintering

Hotspots for soil damage are created when feeding silage and concentrates in fields to outwintered stock.

“Sheep snackers are better than concentrate feeding in a trough, as nuts are spread out. Similarly, bales can be rolled out, though you need to do feed budgets to ensure cattle clear it up and don’t waste silage.”

Slurry applications

Damaged swards should not receive high applications of slurry at this time, to avoid vehicle traffic and because waterlogged soils have water-filled pores and less oxygen.

“Overloading with slurry will just produce ammonia or hydrogen sulphide gases and limit biological activity,” says Chris.