In other situations, erosion control can be achieved by implementing a single practice, where the erosion is minimum, such as the establishment of grassed waterways.
The most effective way to control erosion is to maintain a permanent surface cover on the soil surface, such as pasture or meadow. Therefore, areas that are highly susceptible to water or wind erosion need to be considered for soil conservation programs. Soil losses in Iowa due to water erosion and surface runoff can contribute a great deal to surface water quality concerns.
Many studies indicate that soil erosion results in large decreases in soil productivity. In a study conducted at Iowa State University on 40 soil associations, Craft and coworkers Proceedings of the National Symposium on Erosion and Soil Productivity , reported that the impact of soil erosion on soil productivity was largely determined by subsoil properties because they effect root growth, soil water availability, and plow layer fertility.
Thus, the loss of the topsoil can have considerable impact on yield, where nutrient availability, root growth environment, and soil water availability are essential for plant development. In soils with unfavorable subsoil conditions, erosion can have a large effect on productivity, if the plow layer soil fertility is not restored. Plant residue management is another way of controlling soil erosion by intercepting raindrops, thereby reducing surface runoff and protecting soil surface particle detachment by raindrop impact.
Crop residue can provide an excellent soil cover after harvest and enhance snow harvesting during the off season, improve soil water intake by preventing soil surface sealing due to raindrop impact, and consequently, reduce surface runoff. Equally important in minimizing soil erosion is the adoption of a cropping system along with conservation tillage practices such as no-till, strip-till, and ridge-till.
The degree of effectiveness of different tillage practices depends on the degree of soil manipulation, which effects the residue distribution on the soil surface. Table 1 shows combinations of different cropping systems and the relative scale of erosion hazard associated with each system.
However, the excessive use of phosphoric chemicals ends up causing an imbalance of microorganisms in the soil moisture, stimulating the growth of harmful bacteria. As the soil gets degraded, the risk of erosion increases and the sediments sweep via the actions of water and wind into rivers and nearby regions, possibly contaminating nearby ecosystems. At the same time, tillage techniques that turn over crops and forages commonly used by farmers to prepare seedbeds by incorporating manure and fertilizers, leveling the soil and taking out invasive seeds also have a large impact.
Instead, it runs off to flood nearby lands, speeded up erosion in these areas. Moreover, motor-based activities such as motocross also have the potential to disturb ecosystems and change even if at a smaller scale compared with other causes and erode the soil.
Soil is a very important resource that allows the production of food, fiber, or forages. Despite it being a renewable resource, it renews slowly — generating three centimeters of topsoil takes 1, years. Therefore, protecting it is very important to bet on long-term, sustainable agricultural practices since one of the main issues associated with soil erosion is that it comes along a decrease in soil productivity.
These productivity losses reduce the quantity and quality of the food we eat. A study based on the results of 40 soil associations reported that the effects of soil erosion on soil productivity were mostly the result of subsoil properties such as soil water availability, root growth or plow layer fertility — which impact yield results.
In the end, with an unfavorable subsoil, erosion is easier and yields and productivity are more greatly affected. Despite the fact human activities have accelerated soil erosion, there are ways of repairing the damage we have created. From reforestation and windbreaks to stone walls or more sustainable agriculture techniques.
Regenerative agriculture techniques have the potential to preserve and restore ecosystems and habitats and improve the quality and health of the soil. Windbreaks are linear plantings of shrubs and trees with the goal of improving crop production, protect the soil, people, and livestock. According to FAO , windbreaks can reduce wind velocities for a distance approximately 15 times the height of the tallest trees.
As a result, there is a lower rate of soil loss across large crop areas. According to Camera et. According to FAO , reforestation helps reduce sedimentation rates in downstream valleys.
According to this UN agency, reforestation on unstable land and around water regions such as rivers increases the water-retention capacity of land and improve water quality, both of which benefit food production. Moreover, according to a recent study published in Nature , reforestation also has a tremendous potential to help fight climate change as trees capture huge amounts of CO2. Conservation tillage stands for as any form of tillage that minimizes the number of tillage passes.
Conservation tillage techniques have the potential to reduce the vertical movements of soil. In this way, more crop residues are left on the soil surface reducing the exposure to water or wind erosion. FAO, bringing attention to the fact that a lthough soils are essential for human well-being and the sustainability of life on the planet, they are threatened on all continents by natural erosion.
The dirt beneath our feet is getting poorer and on many farms worldwide, there is less and less of it. Quote by Franklin D. Soil is lost rapidly but replaced over millennia and this represents one of the greatest global threats for agriculture. Rill erosion results when surface water runoff concentrates, forming small yet well-defined channels Figure 4. These distinct channels where the soil has been washed away are called rills when they are small enough to not interfere with field machinery operations.
In many cases, rills are filled in each year as part of tillage operations. Figure 4. The distinct path where the soil has been washed away by surface water runoff is an indicator of rill erosion. Gully erosion is an advanced stage of rill erosion where surface channels are eroded to the point where they become a nuisance factor in normal tillage operations Figure 5. There are farms in Ontario that are losing large quantities of topsoil and subsoil each year due to gully erosion.
Surface water runoff, causing gully formation or the enlarging of existing gullies, is usually the result of improper outlet design for local surface and subsurface drainage systems. The soil instability of gully banks, usually associated with seepage of groundwater, leads to sloughing and slumping caving-in of bank slopes.
Such failures usually occur during spring months when the soil water conditions are most conducive to the problem. Gully formations are difficult to control if corrective measures are not designed and properly constructed. Control measures must consider the cause of the increased flow of water across the landscape and be capable of directing the runoff to a proper outlet.
Gully erosion results in significant amounts of land being taken out of production and creates hazardous conditions for the operators of farm machinery. Figure 5. Gully erosion may develop in locations where rill erosion has not been managed.
Natural streams and constructed drainage channels act as outlets for surface water runoff and subsurface drainage systems. Bank erosion is the progressive undercutting, scouring and slumping of these drainageways Figure 6. Poor construction practices, inadequate maintenance, uncontrolled livestock access and cropping too close can all lead to bank erosion problems.
Figure 6. Bank erosion involves the undercutting and scouring of natural stream and drainage channel banks. Poorly constructed tile outlets also contribute to bank erosion.
Some do not function properly because they have no rigid outlet pipe, have an inadequate splash pad or no splash pad at all, or have outlet pipes that have been damaged by erosion, machinery or bank cave-ins. The direct damages from bank erosion include loss of productive farmland, undermining of structures such as bridges, increased need to clean out and maintain drainage channels and washing out of lanes, roads and fence rows.
The implications of soil erosion by water extend beyond the removal of valuable topsoil. Crop emergence, growth and yield are directly affected by the loss of natural nutrients and applied fertilizers.
Seeds and plants can be disturbed or completely removed by the erosion. Organic matter from the soil, residues and any applied manure, is relatively lightweight and can be readily transported off the field, particularly during spring thaw conditions. Pesticides may also be carried off the site with the eroded soil. Soil quality, structure, stability and texture can be affected by the loss of soil.
The breakdown of aggregates and the removal of smaller particles or entire layers of soil or organic matter can weaken the structure and even change the texture.
Textural changes can in turn affect the water-holding capacity of the soil, making it more susceptible to extreme conditions such as drought. The off-site impacts of soil erosion by water are not always as apparent as the on-site effects. Eroded soil, deposited down slope, inhibits or delays the emergence of seeds, buries small seedlings and necessitates replanting in the affected areas. Also, sediment can accumulate on down-slope properties and contribute to road damage.
Sediment that reaches streams or watercourses can accelerate bank erosion, obstruct stream and drainage channels, fill in reservoirs, damage fish habitat and degrade downstream water quality. Pesticides and fertilizers, frequently transported along with the eroding soil, contaminate or pollute downstream water sources, wetlands and lakes. Because of the potential seriousness of some of the off-site impacts, the control of "non-point" pollution from agricultural land is an important consideration.
Wind erosion occurs in susceptible areas of Ontario but represents a small percentage of land — mainly sandy and organic or muck soils. Under the right conditions it can cause major losses of soil and property Figure 7. Figure 7. Wind erosion can be severe on long, unsheltered, smooth soil surfaces. Soil particles move in three ways, depending on soil particle size and wind strength — suspension, saltation and surface creep.
Sustainable land practices need to be financially viable for farmers. Governments and banks must help farmers get access to credit and support in implementing erosion prevention. This is not only a good deal for the farmer, but for the whole community. The key to managing and reducing soil erosion is to rehabilitate already-damaged land , stop further degradation and put erosion-preventative measures at the core of land management policy.
In this way, we can help prevent hunger and mitigate the climate crisis. To learn more about WRI's work restoring eroded soils, click here. WRI relies on the generosity of donors like you to turn research into action. You can support our work by making a gift today or exploring other ways to give.
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