Source: FAO. 2019. Soil erosion: the greatest challenge to sustainable soil management. Rome. 100 pp. Licence: CC BY-NC-SA 3.0 IGO.
Significance: (S)oil erosion by water, wind and tillage continues to be the greatest threat to soil health and soil ecosystem services in many regions of the world. It is considered to be the number one threat to soil functions in Africa, Asia, Latin America, Near East and North Africa, and North America; in the first four of these regions, the trend for erosion was deteriorating. Only in Europe, North America and the Southwest Pacific was the trend in erosion improving.
Rates of Soil Erosion:
There are major discrepancies among the global estimates of erosion rates and of tolerable loss and these differences are, in large part, attributable to the methods used to make the estimates. While the differences are understandable from a scientific perspective, they do complicate the ability of the scientific community to gain the attention of soil users, policy makers and politicians, who are essential for devising and implementing soil control measures. Ideally local estimates of soil erosion rates need to be coupled with locally appropriate estimates of tolerable soil loss so that decision makers can reliably assess the urgency of erosion control implementation.
Estimates of soil loss rates differ substantially depending on the method used to derive them. Estimates of loss from field plots are typically much higher than those estimated from models (e.g., >10x).
Global values of estimated erosion range from 0.2-0.6 mm/year to 3.9 mm/year. A median value of 1.5 mm/year has been estimated by several researchers.
Soil production rates: 0.173 mm/year (A mean value from a survey of 188 papers)
Mean rate of soil lowering: 3.9 mm/year