Tillage farming damaging earthworm populations, say scientists

May 08, 2017

The digging, stirring and overturning of soil by conventional ploughing in tillage farming is severely damaging earthworm populations around the world, say scientists.

The findings published in the scientific journal Global Change Biology show a systematic decline in earthworm populations in soils that are ploughed every year. The deeper the soil is disturbed the more harmful it is for the earthworms.

The scientists from the University of Vigo, Spain, and University College Dublin, Ireland, analysed 215 field studies from across 40 countries dating back as far as 1950. Each of the studies investigated earthworm populations under conventional tillage and other forms of reduced tillage.

"What we see is a systematic decline in the earthworm population in the soil after continued ploughing and a significant increase in the abundance of earthworms in less disturbed soil, although some soils would need more than 10 years to show good signs of recovery" says Associate Professor Olaf Schmidt, from the UCD School of Agriculture and Food Science, University College Dublin.

According to the findings, the earthworm populations most vulnerable to tillage are larger earthworms that move between layers of soil and create permanent burrows between them (anecic earthworms). Small earthworms that live in the top layers of soil and convert debris to topsoil (epigeic earthworms) were also found to be highly susceptible.

Farming practices that involve no-tillage, Conservation Agriculture and shallow non-inversion tillage were shown to significantly increase earthworm populations. The scientists note that these reduced tillage practices are increasingly being adopted world-wide due to their environmental benefits in terms of erosion control and soil protection.

"Our study also identifies the conditions under which earthworms respond most to a reduction in tillage intensity. These findings can be translated into advice for farmers in different parts of the world", explains Professor Maria Briones from the University of Vigo.

"For example, strong results are achieved in soils with higher clay contents (>35%) and low pH (<5.5), and retaining organic harvest residues amplifies the effects. The controversial herbicide glyphosate did not significantly affect earthworm population responses to reduced tillage."

Earthworms are critical to the maintenance of soil functions and the ecosystem services we expect from them. The great evolutionary biologist, Charles Darwin called earthworms "nature's plough" because they continually consume and defecate soil enhancing its fertility in the process.

In his experiments in England in the late 1800s, Darwin found about 54,000 earthworms inhabited each acre of land and that each of these populations turn over tens of tons of topsoil every year.

Recognizing the critical ecological value of earthworms, Darwin wrote: "It may be doubted whether there are any other animals which have played so important a part in the history of the world as have these lowly, organized creatures."

Professor Maria Briones concludes "Switching to reduced tillage practices is a win-win situation for farmers because they save costs and in return larger earthworm populations help in soil structure maintenance and nutrient cycling."
-end-


University College Dublin

Related Agriculture Articles from Brightsurf:

Post-pandemic brave new world of agriculture
Recent events have shown how vulnerable the meat processing industry is to COVID-19.

Agriculture - a climate villain? Maybe not!
The UN's Intergovernmental Panel on Climate Change (IPCC) claims that agriculture is one of the main sources of greenhouse gases, and is thus by many observers considered as a climate villain.

Digital agriculture paves the road to agricultural sustainability
In a study published in Nature Sustainability, researchers outline how to develop a more sustainable land management system through data collection and stakeholder buy-in.

Comparisons of organic and conventional agriculture need to be better, say researchers
The environmental effects of agriculture and food are hotly debated.

EU agriculture not viable for the future
The current reform proposals of the EU Commission on the Common Agricultural Policy (CAP) are unlikely to improve environmental protection, say researchers led by the German Centre for Integrative Biodiversity Research (iDiv), the Helmholtz Centre for Environmental Research (UFZ) and the University of Göttingen in the journal Science.

Global agriculture: Impending threats to biodiversity
A new study compares the effects of expansion vs. intensification of cropland use on global agricultural markets and biodiversity, and finds that the expansion strategy poses a particularly serious threat to biodiversity in the tropics.

A new vision for genomics in animal agriculture
Iowa State University animal scientists helped to form a blueprint to guide the next decade of animal genomics research.

New pathways for sustainable agriculture
Diversity beats monotony: a colourful patchwork of small, differently used plots can bring advantages to agriculture and nature.

The future of agriculture is computerized
Researchers at the MIT Media Lab Open Agriculture Initiative have used computer algorithms to determine the optimal growing conditions to improve basil plants' taste by maximizing the concentration of flavorful molecules known as volatile compounds.

When yesterday's agriculture feeds today's water pollution
Water quality is threatened by a long history of fertilizer use on land, Canadian scientists find.

Read More: Agriculture News and Agriculture Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.