Soil contamination

As soil degradation is defined as the deterioration of the ecosystem services of soil up to their complete loss. You can be both a natural process, for example, triggered by climate change, as well as by human beings, for example, management of the land without compensation of material removal.

Anthropogenic caused land degradation now destroyed every year land in the magnitudes of Switzerland. Without a functioning soil and thus trapped micro-fauna ecosystem functions and the resulting services, such as the breakdown of dead organic matter, recycling of nutrients and the growing of crops would no longer be guaranteed.

Problem

The soil degradation is a global problem and not a phenomenon of the modern era (see Critias by Plato ), when it assumes ever greater proportions in recent decades. As early as 1997 showed 15% of the ice-free land surface degradation phenomena anthropogenic ( an area larger than the United States and Mexico ), 1 % of which was destroyed to the extent that the recovery of the soil takes no longer possible ist.Die surface of the soil with degradation phenomena always further, in 2008, this area already amounts to 24%. Every year we are losing about 24 billion tons of surface soil, which roughly corresponds to the size of Switzerland. The continents are affected differently by the problem of land degradation. The most intense symptoms of soil degradation are found in Asia, where 39% of the soils are already degraded. Particularly affected are drylands, which account for 40 % of our land area, here is already at 70 % of the surface degradation of the soil. Land degradation is particularly problematic, since it is a gradual process that is perceived only at a late stage. So can lose about 0.1 cm soil a farmer in a heavily rainy night, which already are 1.2 tons lost ground on 1000 m². After 20 years, about 20 cm soil are thus irretrievably lost. It would take nearly 4,000 years to form this new ground. The base can thus, based on a human life may be referred to as a non-renewable resource.

Causes of land degradation

• Destruction of vegetation cover: Mostly by cutting down, burning or overgrazing.
• Mismanagement: monocultures, insufficient supply of organic fertilizers or green manure or manure, excessive farming on slopes, intensive irrigation with poor water quality, inadequate drainage of arable land leads to salinization.
• Intensive use of inorganic fertilizers, contamination with industrial and municipal wastes, air pollution, contaminated sites.
• Destruction of soil structure: compaction by machinery, large livestock holdings or people ( trails ), erosion of soils.

Types and consequences of land degradation

Basically, you can differentiate between the biological, chemical and physical soil degradation.

Biological degradation

• Loss of biodiversity: Moves to the decline of the Lebendverbaus and thus to erosion

Chemical soil degradation

• Depletion of the in- ground carbon pools: Enhances the CO2 content of the air
• PH changes: Run to infertility of the soil
• Soil salinity: Prevents water uptake by plants
• Poisoning: Contamination of soils with inorganic and organic pollutants kills organisms and may lead to contamination of groundwater

Physical soil degradation

• Soil compaction: Destroy the soil pores and thus the habitat of soil organisms and plants, soil respiration is reduced and water is no longer accepted
• Soil sealing: can promote flood, as the water can not penetrate the soil
• Soil loss: The use of land for farmers is no longer possible

Economic and Social Consequences

The destruction of the world's soils leads to an increasing threat to food basis. Because today are already showing 20 % of the agricultural land of the people of degradation. This is particularly threatening because only a small proportion ( 11%) of the land area is fully usable for agriculture. The largest part is too dry (23% ), 10% chemically unbalanced, 6% is too moist, 6% are permafrost. For the rest of the country, that the soil is not deep enough for agricultural use. 1.5 million people are directly affected by the degradation of the soil. Over the next 25 years is expected to decline in food production between 15 and 35 %. Especially in the poorer regions of the crop failures due to degraded soils can not be buffered by improved crops. This can lead to mass migrations in the respective areas. For the next 10 to 20 years of global environmental change, including desertification and land degradation include, expected economic damages in the amount of 5 billion U.S. dollars. In addition to the loss of soil as a food source by soil degradation are the biogeochemical cycles disturbed, such as the water cycle. The loss of the soil also reduces its function as storage for greenhouse gases and thus amplifies climate change.

Soil degradation in Europe

Although Europe with only 11% of degraded surface is below the global average, show up in each region a strong impact. In Europe, soil compaction is due to the population density of a particular problem. An example of this is the Ukraine, with about 40 % compressed Boden.In Germany are already degraded over 30,000 km ² ground, these are more than 9 % of the total. Much stronger the Mediterranean area in Europe is affected, 157 million hectares are threatened there by soil erosion and other four million of the soil salinity. Especially in these places, tourism has an additional negative impact on the ground. The different European soils are the result of geography, topography, climate and the distribution of loads. The Mediterranean climate makes regions particularly sensitive to soil degradation (especially erosion). Deforestation in these areas and the increase in forest fires have severely degraded the soil since the time of the Romans. Today, there are areas where there simply is no more ground, which could further degrade. The same applies to regions in Eastern Europe. In the Western States, it shows the problem of soil sealing as particularly dramatic. So already 16-20 % of the area ( industrial plants, roads, etc. ) are sealed in densely populated countries such as Belgium and Denmark. The soil contamination by toxic substances is problematic throughout Europe, as these substances also increasingly enter the groundwater. Dirty glass show, for example in Poland already 35 % of the land surface acidification phenomena.