World Soil Day

  Despite almost a century of research and extension efforts, soil 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. Our understanding of the physical processes of erosion and the controls on those processes has been firmly established. Nevertheless, some elements remain controversial. It is often these controversial questions that hamper efforts to implement sound erosion control measures in many areas of the world. Regional and global estimates of soil loss rates due to erosion differ substantially depending on the method used to derive them. Generally, estimates of mean annual soil loss from field plots are substantially higher (8 to almost 50 t ha-1 yr-1) than those from regional and global models (2 to 4 t ha-1 yr-1). Any estimate of erosion must also be placed in the context of the acceptable or tolerable rate of loss. Rates of tolerable soil loss calculated using soil production rat...

  Healthy soils are the basis for healthy habitats for all living beings. They provide food, clean water, raw materials and various ecosystem services. But salinity, acidification and loss of biodiversity are just some of the threats that soils are currently facing. This year’s World Soil Day commemoration focuses on reversing soil erosion for our future. “We are celebrating a treasure beneath our feet which hosts a quarter of the planet’s biodiversity and provides about 95% of our food” , said Eduardo Mansur, FAO ’s Director of the Land and Water Division. Unsustainable agriculture practices and other improper land use changes, such as illegal deforestation, can accelerate erosion up to a thousand times, according to FAO. Soil erosion affects soil health and productivity by removing the highly fertile topsoil and exposing the remaining soil. It decreases agricultural productivity, degrades ecosystem functions and amplifies hydrogeological risk, such as landslides or floods. “Soi...

  Soil erosion is the displacement of the upper layer of soil and can be caused by wind, water or anthropogenic activities such as soil tillage. It can be measured in the field, by Observing visible evidence of soil loss , in complement to the measure of topsoil soil organic matter. In identified cases of soil erosion , it is recommended to implement different assessment methods, such as the USLE method, the synthesis of satellite imagery and its metadata, or direct measurement of erosion in gullies, rills, sheet wash, landslides using erosion pins, sediment yield downhill or in drains using Gerlach boxes, or undercutting of the soils around trees and fence-lines.

  The SWSR report identified soil erosion by water and wind as the most significant threat to global soils and the ecosystem services they provide. Soil erosion causes the loss of surface soil layers containing organic and mineral nutrient pools, partial or complete loss of soil horizons and possible exposure of growth-limiting subsoil, as well as off-site impacts such as damage to private and public infrastructure, reduced water quality and sedimentation. Soil erosion is accelerated by human activities through, amongst others, reduced plant or residue cover, tillage and other field operations, and reduced soil stability leading to soil creep and landslides. • Land-use changes such as deforestation or improper grassland-to-cropland conversion that cause removal of surface cover and loss of soil carbon should be avoided or carefully planned and appropriately implemented if unavoidable; • A cover of growing plants or other organic and non-organic residues that protects the soil surf...