James Ingles, head of agriculture at Barenbrug, says after long-term flooding, the sward may ‘green up’ when it dries out, but this will be with non-productive weed grasses such as meadow grass.
“The only answer is to reseed with productive species, ideally by ploughing, which has the benefit of opening up and drying out the soil structure. If that is not possible, harrow out any mat of dead material, before direct drilling a specialist overseeding mixture.”
He adds short-term flooding and waterlogging causes two main problems; the soils rapidly lose oxygen, and the passage of water through the soils leads to the leeching of the more soluble nutrients, like nitrogen, sulphur and potash.
Mr Ingles says applying fertiliser to compacted and waterlogged soils is likely to be a waste of time and money, as the plant will not be able to fully utilise it. He also says soils which are waterlogged stay colder for longer, further reducing growth and making the production problem worse.
“To get the soils and swards back into full production, dig a test hole about 50cm square and at least 40cm deep. This will allow you to see how deep the problem is, often waterlogging is caused by a shallow pan caused by either grazing animals or tractor activity. This can be corrected by either slitting the sward or the use of a sward lifter.”
Docks could pose bigger problems than usual for grassland farmers this spring, as the mild winter has encouraged early perennial weed growth, according to David Roberts, grassland agronomist for Dow AgroSciences.
“Of course, we could still get a cold snap, but the trend for soil temperatures across the country is now upwards,” he says.
“On many farms in the South, grass is growing which means the weeds are too – even in areas where the ground has been under water.
Docks, with their extensive root systems are able to seek out aerated soil – so excessive wet conditions do not really hold them back.
They are in their ‘starting blocks’ and ready to grow.
“The most effective time to try and control docks is early in the season before they gain a foothold,” advises Mr Roberts.