Worms driver for fer­til­ity

Matamata Chronicle - - Rural Delivery -

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.

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