Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 


Good turns of the humble worm

Good turns of the humble worm

by Bala Tikkisetty
February 14, 2014

The humble earthworm is worth its weight in gold when it comes to on farm soil productivity and protecting waterways from the impacts of farming.

Common earthworms introduced from Europe by pakeha settlers in the 1800s improve the general condition of farming soils, reduce surface runoff of contaminants from pasture and prevent soil erosion generally.

These introduced earthworms are, in fact, essential to the development of fertile productive soil. They act as biological aerators and physical conditioners of the soil, improve soil porosity, structure, aggregate stability and water retention.

Earthworms also increase the population, activity and diversity of soil microbes, such as actinomycetes and mycorrhizal fungi. These microbes play a vital role in the supply of nutrients to pasture, digesting soil and fertiliser and unlocking nutrients such as phosphorus that are fixed by the soil.

Soils without enough of the right type of earthworms are usually poorly structured and tend to develop a turf mat or thatch of slowly decomposing peat-like material at the surface. Old dung and dead plant material lie about the surface. These factors can naturally inhibit pasture and crop production.

Lower producing grasses are often more evident than ryegrass on these types of soils as well. Pasture growth is slow to start in spring and stops early in autumn.

Plant nutrients tend to remain locked in the organic layer and there is poor absorption of applied fertiliser.

Plants roots in such soils are relatively shallow and pastures are therefore susceptible to drought.

And, as indicated earlier, water runs off this type of pasture more easily rather than being absorbed into the soil, increasing water quality problems.

To help avoid these types of problems, soils should have a good diversity of relevant earthworm species.

The most common introduced earthworm in New Zealand is Aporrectodea calignosa, a topsoil dweller. This earthworm grows up to 90 millimetres long and may vary in colour from grey to pink or cream. Another very common introduced earthworm is Lumbricus rubellus, a surface dweller. Often found under cow pats, this earthworm will grow up to 150 mm long. It is reddish-brown or reddish-purple colouring with a pale underside and flattened tail. Aporrectodea longa live in burrows as deep as 2-3 metres below the surface.

Undertaking an earthworm count will let farmers know if they have enough of the right type. Counts should preferably be done late winter to early spring when soil moisture and temperature conditions are ideal. Counts can be done by taking out a 20 centimetre cube of soil with a spade. Aim to have an earthworm number of between 30 and 35 in that cube.

If soils are scoring way below that there is a range of ways to increase their populations:
• Ensure soil calcium levels are near 7 as calcium promotes earthworm reproduction.
• Maintain soil pH between 5.8 – 6.3.
• Limit use of fumigants and other pesticides.
• Reduce ammonium-based fertilisers as they make soils acidic.

Also, moist soils promote earthworm spread and activity and more will remain active in topsoil during summer under irrigation. Direct drilling and no tillage cultivation methods is another way to promote help earthworm numbers. Use a mould board or disc plough rather than a rotary hoe. Cropping farms should include a phase of pasture in their cropping rotation to increase organic matter returns.

*************

Bala Tikkisetty is a sustainable agriculture coordinator at Waikato Regional Council.

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

Two Dead, One Injured: Suspect Charged After Ashburton Shooting

Russell John Tully has appeared in Christchurch District Court. Tully has been remanded in custody on charges of murder of Peg Noble and Leigh Cleveland and attempted murder of Lindy Curtis.

The victim’s families and the victim have requested that their privacy be respected and will not be making a statement at this time.

Police have formed a picture of what has occurred yesterday and are appealing for further information and sightings .... More

 

Parliament Today:

John Key Press Conference: Ashburton Shootings, Judith Collins Inquiry

Prime Minister John Key has delayed the release of Nationals’ fiscal policy in light of this morning’s shooting at a Work and Income office in Ashburton... Key also answered questions about Judith Collins, and confirmed that independent inquiry will be held with regard to allegations made against Collins. More>>

ALSO:

Internet MANA: Georgina Beyer Rocks The Waka

“There is now, and always will be, a range of views about many issues within our movement and members are free to express them, but Georgina’s views on Kim Dotcom are not shared by the MANA Movement leadership or the vast majority of MANA members and supporters around the country” states MANA Candidate for Waiariki, Annette Sykes. More>>

ALSO:

IGIS Update: Inquiry Into Release Of NZSIS Information

The Inquiry would be conducted in private and individuals would appear before her separately over a period of more than a week. She does not intend to name those summoned to give evidence until her report is published. “I can confirm that all persons summoned will be required to appear under oath...” More>>

ALSO:

Gordon Campbell:
On John Key’s ‘Blame It On Judith’ Strategy

Right now, Prime Minister John Key seems intent on limiting the scope of any inquiry into his government’s dealings with Cameron Slater. The declared aim is to make that inquiry solely about Judith Collins’ behavior with respect to the Serious Fraud Office. More>>

ALSO:

Maori Council Lawyers' Statement: Supreme Court Decision On Maori Water Rights

“…the Supreme Court refused to give Pouakani people what they asked for, but may have given them something much, much better instead… the Supreme Court has questioned whether the Crown owns the River at all.” More>>

ALSO:

Gordon Campbell: On The Debate, And The Collins Accusation

Debating is a peculiar discipline in that what you say is less important than how you’re saying it. Looking poised, being articulate and staying on topic generally wins the day – and on that score, Labour leader David Cunliffe won what turned out to be a bruising encounter with Prime Minister John Key last night on TVNZ. More>>

ALSO:

Gordon Campbell: On Winston Peters' Latest Bout Of Immigrant Bashing

It is only one poll, but rather than cannibalising each other's vote, Colin Craig and Winston Peters do seem to be managing to find the room to co-exist... Few are questioning how Peters got to this happy place, and what it says about the mood of the electorate. More>>

ALSO:

More Immigration News: First People Trafficking Charges

The first people trafficking charges in New Zealand have been brought by Immigration New Zealand (INZ)... The defendants have been charged under the Crimes Act 1961 for arranging by deception the entry of 18 Indian nationals into New Zealand. More>>

Collins 'Misinterprets Media Reports': "Too Compromised To Remain Justice Minister"

Bizarre claims by Judith Collins this morning that she had been cleared of inappropriate behaviour by the Privacy Commissioner demonstrates she is too compromised to remain Justice Minister, Labour MP Grant Robertson says. More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news