We'll rise or fall on the quality of our soil

Nov 04, 2013

Great civilisations have fallen because they failed to prevent the degradation of the soils on which they were founded. The modern world could suffer the same fate.

This is according to Professor Mary Scholes and Dr Bob Scholes who have published a paper in top scientific journal, Science, which describes how the productivity of many lands has been dramatically reduced as a result of , accumulation of salinity, and nutrient depletion.

"Cultivating continuously for too long destroys the bacteria which convert the into nutrients," says Mary Scholes, who is a Professor in the School of Animal, Plant and Environmental Sciences at Wits University.

Although improved technology – including the unsustainably high use of , irrigation, and ploughing – provides a false sense of security, about 1% of global land area is degraded every year. In Africa, where much of the future growth in agriculture must take place, erosion has reduced yields by 8% and nutrient depletion is widespread.

"Soil fertility is both a biophysical property and a social property – it is a social property because humankind depends heavily on it for food production," says Bob Scholes, who is a systems ecologist at the Council for Scientific and Industrial Research.

Soil fertility was a mystery to the ancients. Traditional farmers speak of soils becoming tired, sick, or cold; the solution was typically to move on until they recovered. By the mid-20th century, soils and plants could be routinely tested to diagnose deficiencies, and a global agrochemical industry set out to fix them. Soil came to be viewed as little more than an inert supportive matrix, to be flooded with a soup of nutrients.

This narrow approach led to an unprecedented increase in food production, but also contributed to global warming and the pollution of aquifers, rivers, lakes, and coastal ecosystems. Activities associated with agriculture are currently responsible for just under one third of greenhouse gas emissions; more than half of these originate from the soil.

Replacing the fertility-sustaining processes in the soil with a dependence on external inputs has also made the soil ecosystem, and humans, vulnerable to interruptions in the supply of those inputs, for instance due to price shocks.

However, it is not possible to feed the current and future world population with a dogmatically "organic" approach to global agriculture. Given the large additional area it would require, such an approach would also not avert climate change, spare biodiversity, or purify the rivers.

To achieve lasting food and environmental security, we need an agricultural soil ecosystem that more closely approximates the close and efficient cycling in natural ecosystems, and that also benefits from the yield increases made possible by biotechnology and inorganic fertilisers.

Explore further: Call for food revolution based on soil health

add to favorites email to friend print save as pdf

Related Stories

Digging deeper for soil carbon storage

Sep 10, 2013

Many surface soils in Western Australia are already storing as much carbon as they can, according to research at The University of Western Australia and in collaboration with the Department of Agriculture ...

Urban soil quality and compost

Oct 15, 2013

With higher populations and limited space, urban areas are not often thought of as places for agriculture. A recent surge in community gardens, though, is bringing agriculture and gardens into the cities. And certain byproducts ...

Recommended for you

EU leaders seek last-minute climate deal

2 hours ago

European Union leaders came under pressure Thursday to strike a deal aimed at bolstering Brussels as a trailblazer in fighting global climate change as negotiations went down to the wire.

Research team studies 'regime shifts' in ecosystems

5 hours ago

The prehistory of major ecological shifts spanning multiple millennia can be read in the fine print of microscopic algae, according to a new study led by researchers at the University of Nebraska-Lincoln.

User comments : 0