what is a reliable process to prevent degradation

Factsheet Cake Body

(Adjusted from BALLAYAN 2000 and INFONET-BIOVISION 2010)

Soil degradation is a global process, but affects arid and semi-arid zones in sub-Saharan Africa near. Soil degradation is increasing worldwide, specially in the countries within the torrid zone. Depletion of nutrients and soil organic matter and erosion are the principal forms of soil deposition (see too nutrient requirements).

Amid the country used for agriculture and forestry, soil is an important component. The intensive and increasing pressure on land leads to its degradation and pollution, which may result in a fractional or complete loss of its productive chapters. Soil degradation tin can be divers every bit a procedure by which one or more of the potential ecological functions of the soil are harmed or destroyed. Soil degradation is a process that lowers the current and/or hereafter capacity of the soil to produce goods and services.

Soil degradation can be either a result of natural hazards or due to unsuitable land use and inappropriate state management practices. Mismanagement of arable areas by farmers, cultivation practices that are non adjusted to local environments and overgrazing past livestock are seen as the major causes of soil deposition.

Natural hazards which tin lead to soil degradation include land topography and climatic factors such as steep slopes, frequent floods and tornadoes, bravado of high velocity air current, rains of high intensity and drought conditions in dry regions. The most prominent degradation feature worldwide is erosion by h2o.

Cultivating and managing soils in a more than sustainable style would reduce environmental pressures all over the world: When crops are harvested, organic material and nutrients are removed from the fields (see also the food bike). While artificial fertilisers supercede - to some extent - the loss of nutrients, they do not supersede the loss of organic material. Over time, this seriously reduces soil quality, leading to soils with a lower water property capacity, less air, and soils that are more susceptible to erosion and hence likewise degradation.

Man-induced soil degradation effectually the globe. Source: ISRIC et al. (1996)

Types of soil deposition

Soil degradation tin can exist classified into four main types of degradation: h2o erosion, air current erosion, chemical deterioration and physical deterioration.

Water erosion

(Adjusted from BALLAYAN 2000 and INFONET-BIOVISION 2010)

Water erosion ways that soil particles are detached either by splash erosion (acquired by raindrops), or by the result of running water. Water erosion is influenced by four factors: rainfall, soil blazon, gradient gradient, and soil use/vegetation encompass (INFONET-BIOVISON 2010).

• Rainfall: The impact of raindrops on the soil surface can break downward soil aggregates and disperse the aggregate cloth over the surface. Lighter amass materials such every bit very fine sand, silt, dirt and organic matter tin exist easily removed by the raindrop splash and runoff water. Greater raindrop energy or runoff amounts might be required to movement the larger sand and gravel particles. Runoff tin occur whenever there is backlog water on a slope that cannot be absorbed into the soil or trapped on the surface. The amount of runoff can exist increased if infiltration is reduced due to soil compaction, crusting or freezing.

• Soil blazon: Soil erodibility is an estimate of the power of soils to resist erosion, based on the concrete characteristics of each soil type. In general, soils with faster infiltration rates, higher levels of organic matter and improved soil structure have a greater resistance to erosion. Sand, sandy loam and loam-textured soils tend to exist less erodible than silt, very fine sand, and certain clay textured soils.

• Gradient gradient: Naturally, the steeper the slope of a field, the greater the amount of soil loss from erosion by h2o. Soil erosion past h2o too increases as the slope length increases due to the greater aggregating of runoff.

• Soil apply: Plant and residue cover protects the soil from raindrop impact and splash, tends to ho-hum down the motility of surface runoff and allows excess surface water to infiltrate.

Case of gully erosion. Source: Constitute and SOIL SCIENCES ELIBRARY (2005)

There are four dissimilar types of water erosion (BALLAYAN 2000):

• Sheet erosion: This means when a adequately compatible layer of soil is removed over an unabridged surface expanse.

• Rill erosion: This occurs where water runs in very small channels over the soil surface, with the abrading issue of transported soil particles causing deeper incision of the channels into the surface.

• Gully erosion: This type of erosion occurs when rills menstruation together to make larger streams. They tend to become deeper with successive flows of h2o and can get major obstacles to cultivation.

• Bank erosion: This is acquired by water cutting into the banks of streams and rivers. It can be very serious at times of big floods and crusade major destruction to holding.

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Current of air erosion

(Adapted from SHELTON 2003)

Wind erosion in New United mexican states. Source: RITTER (2003)

The rate and magnitude of soil erosion past air current is influenced past the following factors:

• Erodibility of soil: Wind can append very fine particles and and so transport it over corking distances. Fine and medium size particles can be lifted and deposited, while fibroid particles can be blown along the surface (commonly known as the saltation result).

• Soil surface roughness: Soil surfaces that are non crude or ridged offer petty resistance to the wind. However, over time, ridges can be filled in and the roughness broken down by abrasion to produce a smoother surface susceptible to the wind.

• Climate: The speed and elapsing of the current of air has a direct connexion to the extent of soil erosion. Soil moisture levels can exist very low at the surface during periods of drought, thus releasing the particles for transport by wind.

• Vegetative cover: The lack of permanent vegetation cover in certain locations has resulted in extensive erosion by wind. Loose, dry, bare soil is the most susceptible. The most effective vegetative encompass for protection should include an adequate network of living windbreaks combined with proficient tillage, rest management, and crop choice.

Chemical deterioration

(Adapted from FAO/AGL 2000)

Chemical deterioration as a type of soil degradation involves loss of nutrients or organic matter, salinisation, acidification, soil pollution, and fertility refuse. The removal of nutrients reduces the chapters of soils to support constitute growth and ingather production and causes acidification. In arid and semi-arid areas problems can arise due to accumulation of salts, which impedes the entry of water in plant roots. Soil toxicity can exist brought about in a number of ways. Typical examples are from municipal or industrial wastes, oil spills, the excessive employ of fertiliser, herbicides and insecticides, or the release of radioactive materials and acidification by airborne pollutants.

Chemic deterioration of soils is oft also due to agronomical over exploitation, relying solely on replenishing food losses through harvesting by artificial fertilisers. Artificial fertilisers nigh ofttimes not able to balance all nutrients, leading to an imbalance in soil. They are besides non able to replenish the loss of organic affair, which is important for food absorption. Furthermore, artificial fertilisers tin can be polluted (e.g., phosphate rock is often radioactively contaminated).

Physical deterioration

(Adjusted from FAO/AGL 2000)

Physical deterioration involves soil crusting, sealing and compaction and tin can be acquired by several factors like compaction through heavy machines or animals. This problem occurs in all continents, under nearly all climates and soil physical conditions, merely has increased with the employ of heavy mechanism. Soil crusting and compaction tend to increase runoff, decrease the infiltration of water into the soil, prevent or inhibit plant growth and leave the surface blank and subject to other forms of degradation. Severe crusting of the soil surface because of breakup of soil aggregates tin can inhibit water entry into the soil and prevent seedling emergence.

Human causes of erosion

(Adapted from ACS Distance Instruction 2009)

The following list gives an overview of human deportment which can crusade erosion and therefore pb to soil degradation:

• Poor agronomical practices such every bit ploughing soil to support cultivated plants or ploughing soil in areas where rainfall is insufficient to back up continuous plant growth.
• Exposing soil on slopes.
• Removal of woods vegetation.
• Overgrazing.
• Altering the characteristics of streams which cause bank erosion.
• Causing increased peak water discharges (increased erosion power) due to changes in hydrological regimes, past such means every bit altering the efficiency of channels (aqueduct straightening).
• Reducing evapotranspiration losses as a result of vegetation removal.
• Production of impervious surfaces such as roads and footpaths, preventing infiltration into the soil and causing increased runoff into streams.

Command of erosion

(Adapted from ACS Altitude Education 2009)

As erosion is caused past the furnishings of wind and water, control methods are more often than not aimed at modifying these effects. The following list describes some of the nearly common control methods:

• Prevention of soil detachment by the use of cover materials such as plants.
• Crop product techniques (e.grand. fertilising with organic fertiliser), to improve soil characteristics and promote plant growth and hence surface encompass.
• Ploughing to destroy rills and contour planting to create small dams across a field, to retard or impound water flow.
• Filling pocket-sized gullies with mechanical equipment or conversion into a protected or grassed waterway.
• Terracing of slopes to reduce rates of runoff.
• Prevention of erosion in the first place past careful pick of land employ practices.
• Conservation tillage methods.
• Armouring of channels with rocks, tyres, concrete and timber to preclude bank erosion.
• The apply of air current breaks to alter wind action.
• Ploughing into clod sizes too big to exist eroded, or ploughing into ridges.

Conclusion

Soils are the basis for the production of food. The area of arable land is limited. Given the growing world population and the area of soils that are already degraded, sustainable land management is crucial. Sanitation practices that reuse nutrients and organic matter present in wastewater and excreta could contribute largely to sustainable soil management, equally they are not merely able to balance food losses, but also replenish organic substances that are lost through harvesting.

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Source: https://sswm.info/sswm-university-course/module-8-water-and-sanitation-future-challenges/further-resources-phosphorus/soil-degradation