Worms driver for fertility
The anatomy of an earthworm is hardly exciting stuff.
But Dr Tim Jenkins, a director at the Centre for Sustainable Agricultural Technologies, has a way of making the bodily functions of an earthworm sound kind of interesting.
He told about 80 farmers at a biological farming seminar recently that earthworms were a key driver of soil fertility.
A good number was 2000 worms per square metre, or about 40 worms per spade, but he often found worm populations around 600sqm to 1000sqm because of poor quality soils.
To improve soil biology Mr Jenkins suggested minimal cultivation, retaining clover, using lime flour and biological fertilisers and avoiding over-grazing.
Worms thrived in soil with a high pH but if it was too high, it would restrict the uptake of trace elements such as copper, zinc and manganese.
A pH of 6 to 6.4 was ideal for a good balance of clover, trace elements and earthworm activity.
Mr Jenkins said the ideal soil texture was ‘‘crumbly’’ as this allowed worms to move freely through the soil which would promote good drainage.
The mucous the worms left behind would also help hold the soil crumbs together in a wet or dry spell.
Mr Jenkins said farmers needed to change their terminology from ‘‘growing grass to growing pasture’’ and he highlighted the importance of legumes. ‘‘Chicory is one of my favourites. ‘‘It has deep roots and it’s efficient at picking up selenium, copper and zinc and it’s very drought tolerant,’’ he said.
The presence of clover was a key indicator of good pasture performance, while broad leaf docks pointed to poor drainage and a lot of daisies were a sign of overgrazing or potassium deficiency, he said.
Worm lover: Dr Tim Jenkins, of the Centre for Sustainable Agricultural Technologies, at the biological farming seminar.