Soil fertility under threat: Wits Scientist

Lazarus Sauti

Mary Scholes, Professor in the School of Animal, Plant and Environmental Sciences at Wits University in South Africa says soil productivity is being severely impacted by erosion, salt accumulation and nutrient depletion.

In a statement, Scholes notes, “Cultivating soil continuously for too long destroys the bacteria which convert the organic matter into nutrients.”

Scholes and Dr Bob Scholes, ecologist at the Council for Scientific and Industrial Researcher, have published a paper in the journal Science, describing how this happens.

The statement also says: “Although improved technology – including the unsustainably high use of fertilisers, irrigation, and ploughing – provides a false sense of security, about 1 percent 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 percent and nutrient depletion is widespread.”

Bob Scholes says, “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.”

The statement says that 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.