What Is Soil Erosion?
When things erode, they wear away due to some force acting on them. Just look at any coastline, and you will notice how the constant pounding force from wind and waves causes erosion of the rocky structures, leaving behind all kinds of interesting cliffs, caves and structures. Soil is not immune to erosion, and like rocks along a coastline, soil can erode due to the effects of forces, such as water, wind and farming practices. In this blog, we will learn about soil erosion and the factors that cause it.
Soil is naturally created when small pieces of weathered rocks and minerals mix with organic materials from decaying plants and animals. Soil creation is a slow process, taking many years. However, the soil that is created is constantly subjected to natural and manmade forces that disrupt it.
Soil erosion is defined as the wearing away of topsoil. Topsoil is the top layer of soil and is the most fertile because it contains the most organic, nutrient-rich materials. Therefore, this is the layer that farmers want to protect for growing their crops and ranchers want to protect for growing grasses for their cattle to graze on. Here are a few types of erosion can occur.
Water Erosion and Surface Water Runoff
One of the main causes of soil erosion is water erosion, which is the loss of topsoil due to water. Raindrops fall directly on topsoil. The impact of the raindrops loosens the material bonding it together, allowing small fragments to detach. If the rainfall continues, water gathers on the ground, causing water flow on the land surface, known as surface water runoff. This runoff carries the detached soil materials away and deposits them elsewhere.
There are some conditions that can accentuate surface water runoff and therefore soil erosion. For example, if the land is sloped, there is a greater potential for soil erosion due to the simple fact that gravity pulls the water and soil materials down the slope. Also, water will have an easier time running across the surface, carrying topsoil with it, if the ground is already saturated due to heavy rains or the soil lacks vegetation to keep the soil in place.
There are different types of soil erosion caused by water. Sheet erosion is erosion that occurs fairly evenly over an area. As raindrops loosen soil, the surface water runoff can transport topsoil in a uniform fashion, almost like a bed sheet sliding off of a bed. This can be so subtle that it might not even be noticed until much of the valuable, nutrient-rich topsoil has already been washed away. If a farmer heads out to his field and sees an accumulation of soil and crop residue at one end of his field, he should be worried about sheet erosion.
Rill erosion is erosion that results in small, short-lived and well-defined streams. When rainfall does not soak into the soil, it can gather on the surface and run downhill, forming small channels of water called rills. You can use this fact as a memory jogger if you remember that 'a little rill will run downhill.' A rill will dry up after the rainfall, but you may still see the stream bed that was created by the temporary stream.
Gully erosion can be thought of as advanced rill erosion. In fact, if rills are not addressed, they will grow into larger gullies. Gully erosion can spell big problems for farmers because the affected land is not able to be used for growing crops, and the big ditches create a hazard for the farmer driving his farm machinery over the fields.
Bank erosion is another type of water erosion and is defined as erosion of the bank of a stream or waterway. As you learned, surface water runoff always moves toward the lowest level due to gravity. Therefore, low-lying streams, rivers and even constructed drainage channels collect water runoff. However, over time, this water activity and other forces naturally wear down the banks lining the waterways.
Like other types of erosion, bank erosion needs to be managed. Otherwise, it can reduce productive farmland and pose a threat to the structural integrity of roads or bridges located near the waterway. This can end up causing the loss of money for farmers and big repair bills for communities. In other words, bank erosion leads to the loss of money or, in slang terms, with bank erosion, you are 'losing bank.
Now that we have a better understanding of what soil erosion is lets look at some simple steps we can take to reduce the natural effects of top soil erosion.
1 Plant grass and shrubs. Bare soil is easily swept away by wind and water, the two main causes of erosion. Plant roots hold the soil together, while their leaves block rain and stop it breaking the soil apart Turf, ornamental grass, and low, spreading shrubs work best, since they cover the soil completely.
If you have any bare ground, try to establish plant cover as soon as possible to limit erosion.
If the ground is mostly flat (slope of 3:1 or less), this might be enough to solve the problem.Steep slopes erode faster, so they need more protection.
Add mulch or rocks. This will weigh down the soil and protect the seeds and young plants underneath from getting washed away. It also slows the absorption of water to reduce runoff. Grass clippings or bark chips work especially well.
If you plant something in the soil, the plant’s roots can hold the soil together. If you don’t plant anything, then keep the soil covered with mulch. You can also add mulch around plants to add another layer of prote
3 Use mulch matting to hold vegetation on slopes. Fiber mulch mats or erosion control mats are a layer of mulch held together in a fiber mesh. This structure holds the mulch together in areas where normal mulch would be washed or blown away.Lay the mat over seeds or young plants.
On steep slopes, dig a small trench at the top of the hill. Lay the top of the mat in the trench, fill it up with soil, then fold the mat back over the top. This helps water run over the top of the mat, where the mat will slow it down, instead of traveling underneath it
4 Put down fiber logs. Another option for erosion control on steep slopes is a series of rolled up logs or "wattles" made from fibrous material (like straw). Water running down the slope will slow down when it hits the logs, soaking into the soil instead of carrying mud downhill. Put the logs down across the slope, 10 to 25 feet (3–8m) apart. Hold them in place with wooden stakes or sturdy, living plants.
You can plant seeds directly in the logs to protect them while they grow.
ction or to keep the soil warm.
Build retaining walls stabilized. A retaining wall at the base of the slope will block the soil and slow down the collapse. This gives grass or other plants time to grow and help the soil hold together.
Give the wall a 2% slope on the side (perpendicular to the incline) so that water flows off to the side instead of pooling.
You may build the wall from concrete blocks, rock, or wood. Only use wood treated with a preservative to prevent rot.
Use retaining walls around flowerbeds and other raised soil areas as well.
Improve drainage. All buildings should have gutters or pipes that can drain water effectively out of your garden and into water collection systems. Without adequate drainage, heavy rain could wash away a whole layer of topsoil.
Areas with heavy water runoff may require you to install underground drainage.
may need local government approval to build these structures.
Reduce watering if possible. Over-watering your garden can speed up erosion by washing away soil. Use less water if you can, or install drip watering system. Since a drip system only delivers small amounts of water at a time, there is no water flooding across the surface to carry topsoil.
You can also install drip lines underground to deliver water directly to the roots.
Avoid soil compaction. When people, animals, or machines travel over soil, they press it down, compacting the soil into a dense layer. Since there is less space between dirt particles in compacted soil, water has a hard time draining through, and carries soil on the surface downhill instead. Walk on paving stones or cleared paths instead of trampling the soil, especially when it is wet. Adding compost or manure can also help by attracting earthworms, which break the soil into looser clumps.
Compacted soil also makes it harder for plants to become established, since the roots have trouble breaking through.
Compaction always lead to net erosion. The water may run off of compacted soil, but as it runs off it generates more force, which can increase the erosion in other area.
these are a few things we can do in our gardens and farms to reduce top soil erosion and improve the over quality of our crops and secure fertile growing mediums,