WELSH farmers are being warned to take soil health seriously or risk poor production as spells of extreme wet and dry weather become commonplace.
Fields with poor soil structure won’t perform in very dry conditions because they can’t absorb and then retain moisture during wetter periods, says NIAB soil scientist Dr Elizabeth Stockdale.
Soils with good structure have a mix of big and small ‘pores’ for moving and retaining water, she told farmers attending a joint Farming Connect and AHDB ‘All Things Soils’ event at Trawscoed Farm, a Farming Connect Innovation Site near Aberystwyth.
“The bigger pores, what I call the ‘motorway pores’, may be no bigger than a human hair but are very important for moving water through soils,’’ said Dr Stockdale.
“The network of little pores, the ‘B roads’, are where water is stored and are where plants draw water from in dry periods.’’
This pore network is disrupted in compacted soils or those where low pH limits biological activity.
To establish the condition of soil Dr Stockdale recommends digging out about a spade-sized block of soil.
To ensure no opportunities are missed, she suggests that farmers carry a spade in every vehicle they use.
Score the whole block to a depth of 30cm using the ‘Healthy Grassland Soils’ assessment tool freely available from AHDB. This document provides a pictorial guide to assessing soils in a grassland situation.
“Always score the whole block according to its worst bit because any part of that block that scores badly will affect the performance of the entire block,’’ Dr Stockdale explained.
A good indicator of soil biology is the earthworm population – in grassland soils with a healthy population expect to find at least 15 and ideally more than 30 in the block, with a variety of species present, according to theAHDB guide – https://ahdb.org.uk/knowledge-library/how-to-count-earthworms.
“Earthworms are really good at getting entwined around the roots so you really need to break up the block to see what is there,’’ Dr Stockdale advised.
Machinery is a major cause of compaction and, on wet ground, 50-80% of damage is caused by the first pass