World ignores soil quality at its peril, may be at risk

Great civilizations have fallen after failing to protect the quality of the soil under their feet a risk that still exists, South African researchers say. The modern world could suffer the same fate as the productivity of many lands has been dramatically reduced through soil erosion, accumulation of salinity and nutrient depletion, researchers Mary Scholes of the University of Witwatersrand and Bob Scholes, an ecologist at the Council for Scientific and Industrial Research, report in a paper published in the journal Science. While the high use of fertilizers, irrigation and plowing provides a false sense of security, about 1 percent of global land area is degraded every year, the Scholeses said. In Africa, where much of the future growth in agriculture must take place, erosion has reduced yields by 8 and nutrient depletion is widespread, they reported. "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," Bob Scholes said. Achieving lasting food and environmental security, the Scholeses said, requires an agricultural soil ecosystem that more closely approximates the close and efficient cycling in natural ecosystems. However, they acknowledged, it is not possible to feed the current and future world population with a dogmatically "organic" approach to global agriculture; it must include the yield increases made possible by biotechnology and inorganic fertilizers.