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

A press release from the University of Witwatersrand: 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 soil erosion, accumulation of salinity, and nutrient depletion.

Mary Scholes“Cultivating soil continuously for too long destroys the bacteria which convert the organic matter 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 fertilisers, 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.

...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.

Soil profile from the US Department of Agriculture