Scientists to investigate mysteries of soil species

The key to sustainable agriculture and higher yields lies in understanding the biodiversity of soil-living species – and yet so little is known about what lies beneath the surface, says the UN’s environment branch. The organisation has announced that it is starting a research programme into these species and what they can do for us.

It is estimated that in one gram of forest soil there are up to 40,000 individual bacterial species – many of which have never been described, according to the United Nations Environment Programme (UNEP). Over half of all known fungi species are soil-living, but it is thought that only 5% of the world’s living species have been described. It is also thought that only 10% of protozoa, 1.5% of nematodes, 5% of mites and 50% of earthworms have been identified.

“There are huge gaps in our knowledge about the variety of organisms in the soil, especially in developing countries,” said Professor Mike Swift of the Nairobi-based Tropical Soil Biology and Fertility Institute. “What we know is the tip of the iceberg.” Biodiversity in the soil has traditionally been the Cinderella subject of the natural world because of the difficulty in seeing what is actually there. New technology such as genetic or DNA screening, similar to techniques used by forensic scientists, can change all that, he says.

As well as discovering new species, one of the project’s aims is to discover whether different vegetation types have an effect on boosting or reducing species diversity in the soil. It appears that planted monocultures cause a sharp decline in soil species, causing negative impacts on moisture content, pest control and fertility, says Swift.

“Whilst these losses can be partially compensated for by the use of petrol-driven agriculture and the use of industrially-produced fertilisers and pesticides, complete substitution is often both biologically and economically inefficient and carried dangers of environmental side-effects,” said Swift. The research project will also be attempting to determine an optimum trade-off between biological and industrial soil management.

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