International Effort to Unearth the Secrets of the Soils
Scientists are to go below ground in seven tropical countries to search for the largest source of untapped life left on Earth.
Experts know that, millimetres below the surface in the twilight, subterranean world, of the earthworm and the nematode, tens of thousands of new species of tiny organisms including bacteria, fungi, insects, mites and worms await discovery.
Scientists are also convinced that unraveling the secrets of how they operate may be the key to restoring the fertility of damaged and degraded lands while helping to raise crop yields in the tropics without the need for heavy pesticide and fertilizer use.
Klaus Toepfer, Executive Director of the United Nations Environment Programme (UNEP), said: ” The life forms living just below our feet are the most understudied organisms on the planet. When people think of where new species might be found, they tend to think of the rainforests, mangrove swamps or place like mountain peaks. Not millimetres below their toes”.
“But researchers are now realizing that the world’s soils, especially those in the tropics, are teeming with life and harbor more undescribed species than dwell on the Earth’s surface. Harvesting the secrets of this understudied realm promises huge benefits and improved knowledge towards the goal of delivering sustainable development, towards eradicating poverty. This is one of the more unusual, curious but absolutely vital projects UNEP has undertaken . So I am delighted that the organization is involved in this pioneering work”.
It was Louis Pasteur, the father of modern microbiology, who observed that “ the role of the very small is large”.
For example earthworms, termites and other soil-burrowing organisms influence the amount of rainwater soils can absorb. Soils depleted in such organisms are more drought-prone and at risk from catastrophic run-off. This can in turn increase the risk of flooding and erosion with consequences for river water quality and habitats such as coral reefs.
Bacteria and fungi help to eliminate pollutants and disease-causing germs from groundwater as it percolates through the soil to reservoirs, boreholes and other sources of drinking water.
Soil-living organisms also play a key role in the release of carbon dioxide, methane and other greenhouse gases from the land to the atmosphere.
Understanding and unravelling the role of these humble creatures and life-forms in the so called “carbon cycle” may help the land absorb more greenhouse gases.
Research has shown that many soil-living organisms attack and neutralize plant, animal and human pests and pathogens It may be possible to promote beneficial soil-dwelling life forms to reduce crop, livestock and human diseases, the researchers believe.
The wealth of new species awaiting discovery, especially in the less well-studied tropics, also represents a huge new genetic resource. It is hoped that this genetic treasure trove will yield an array of new drugs, including antibiotics and 21st century industrial products for the benefit of rich and poor countries alike.
But above all, it is the role of these organisms as “biological ploughs” and suppliers of key nutrients that is intriguing the scientists and which has triggered the new UNEP/GEF project.
In the African savannas the soil structure has largely been formed by termites bringing fertile material to the surface - erosion of this material from the African highlands largely contributed to the fertility of ancient Egyptian agriculture cultivating sediments left by the annual flooding of the Nile.
The ability of termites to re-work iron-hard soils has been used as a tool to reclaim degraded soils in Africa and Australia. Farmers practicing shifting cultivation in West Africa use the mounds of some termite species to judge when fertility has been restored under forest fallow. Scientists showed that the digestive processes of these soil-feeding termites significantly increase the availability of nutrients to plants and are keystones in this traditional agricultural cycle.
Soil organisms also have key roles in modern agriculture.
For example, trials at several 100 year-old tea plantations in the Indian state of Tamil Nadu, where yields have stalled despite heavy use of fertilizers and the spraying of plant growth hormones, indicate that assessing the role of below ground biodiversity can have huge agricultural benefits.
A team from the French Institute de Recherche pour le Development and the University of Sambalpur in India, working with the Indian company Parry Agro,found that, after the re-introduction of earthworms including native species , harvests at some of the plantations are up as much as 282 per cent, and profits up by as much as $ 5,500 per hectare per year. Dr. Fatima Moreira, a soil microbiologist at the Federal University of Lavras in Lavras, Brazil, said nitrogen fixing bacteria were already being deployed in Brazil to boost soya bean harvests in an environmentally-friendly way.
“Soya beans have been inoculated with a species of nitrogen-fixing bacteria called Bradyrhizobium and this has totally replaced the use of industrial fertilizers. An area of Brazil covering 14 million hectares is being farmed this way. Yields are 2.5 tons a hectare and this new technique is saving the national economy about one billion US dollars a year,” she said.
Dr Moreira said surveys have now been carried out on 2,000 species, including trees, shrubs and herbs, in Brazil with the aim of discovering which ones might also be amenable to inoculation by nitrogen fixing bacteria.
Many of these plant species, vital for timber, charcoal and food production, appear likely to benefit from the technology.
The new $26 million project, backed with $9 million funding from the Global Environment Facility (GEF) and support from other donors such as the Rockefeller Foundation, will be initially targeting the “below ground biodiversity” of seven tropical countries. These are Brazil, Mexico, Cote d’Ivoire, Uganda, Kenya, Indonesia and India.
Ahmed Djoghlaf, head of the UNEP/GEF which is based in Nairobi, Kenya, said: “ There is an urgent need to assess, classify and record the life forms below ground. Many people are well aware that increasing intensification of agriculture and the clearing of forests for farmland is contributing to the threat of extinction and a decline in the numbers of plants and animals on the surface. There is growing evidence that a similar impact is being felt below ground. So we maybe losing many important and useful species from the world’s soils without even knowing it.”
Mike Swift, Director of the Nairobi-based Tropical Soil Biology and Fertility Institute of CIAT (TSBF), which is co-ordinating the “Conservation and Sustainable Management of Below-Ground Biodiversity” project, said that the sites in the countries chosen were thought to be among those with the highest below ground biodiversity. Each of the countries also has well-developed scientific capacity in the ‘Cinderella science’ of soil biology.
The project is aimed at boosting those skills further and spreading awareness and knowledge of conserving soils life forms to environmentalists, farmers, government officials and other experts in these and other developing countries.
“There are huge gaps in our knowledge about the variety of organisms in the soil, especially in developing countries. What we know is the tip of the iceberg. One of the reasons why below ground biodiversity has been the Cinderella subject of the natural world has been linked to the difficulty of actually seeing what is there. But we now have new, genetic or DNA screening techniques, similar to those used by forensic scientists to profile a criminal from a swab or sample, which will allows us to screen soil samples for the bacteria, fungi and other life forms, “ said Professor Swift.
He said apart from discovering new species, one of the project’s aims is to test if different kinds of vegetation cover plays a role in boosting or diminishing the diversity of life forms below.
“It appears that, in places where you have single crops or so called mono cultures, planted there is a sharp decline in the level of species below with all sorts of negative impacts on yields, moisture content, pest control and fertility. The natural ability of the soil to break down pollutants, such as agro chemicals, also appears to be compromised,” said Professor Swift.
“Whilst these losses can be partially compensated for by the use of petrol-driven agriculture and the use of industrially-produced fertilizers and pesticides, complete substitution is often both biologically and economically inefficient and carries dangers of environmental side-effects. A major aim of the project is to determine the optimum trade-off between biological and industrial approaches to management of the soil,” he said.
“Agroforestry schemes, in which trees are incorporated into the farmland, or farms where the land has a variety of crops planted, appear to have a more positive impact on life-forms below. We want to test this hypothesis and, if sound, use the results to encourage more diverse kinds of agriculture with multiple benefits,” he added.
Professor Jo Anderson of Exeter University and Chairman of the programme’s Technical Advisory Group, pointed out that there was rising social and economic pressures across the tropics which were leading to widespread destruction of natural habitats for food, fuel and commercial products like timber.
Critical ‘ecosystem services’, such as water supplies, carbon storage and even the local climate, are being compromised along with losses of the very soil organisms that play a key role in providing many of these services.
“This project will provide critical information on how biodiversity can be conserved within landscapes that provide human needs, such as farm land, while conserving the natural heritage of the extraordinarily diverse, and potentially useful communities of organisms, for future generations,” said Professor Anderson.
Nick Nuttall | alfa