Soil

Because its rate of formation is so slow, soil is considered to be a non-renewable resource. Soil formation is influenced by the parent materials (minerals), living organisms (plants, animals, micro-organisms and human activities), climate, topography and weather. Soil is static and thus acts as an enormous receptacle for any type of pollutant mobilised by different triggers (such as acidification) and released into the environment. Since these substances remain in the soil far longer than in the air or water, their impacts are often hidden for a long time.

The most important functions of the soil are to filtrate underground water; hold and supply the nutrients and water necessary for plant growth; provide a habitat for different organisms; contribute to the process of decay; absorb, store and reflect the Sun’s energy; and provide a basis for the existence of human beings and other animals.

• In most cases, the production of food, fodder and renewable raw materials is based in soil. Soil provides nutrients, air and water, and is a medium into which plant roots can penetrate. Serious degradation of the soil by human activities may cause a decrease in food and wood production.
• The filtering, buffering and transforming functions of soil have only been properly recognised in recent decades. These properties enable the soil to prevent harmful substances from reaching the groundwater or food chain. Substances are mechanically filtered, absorbed or precipitated. Some organic substances are decomposed or transformed. This is crucial for groundwater protection, as about 65 percent of the European population depend on groundwater as their main source of drinking water. The soil buffers groundwater against chemical substances and temperature extremes. Acid compounds react with and neutralise the basic cations of sodium, calcium, potassium and magnesium. The soil accumulates pollutants until the buffer capacity is reached. In optimal conditions, more than 99 percent of pesticides are transformed into non-toxic compounds. The remaining 1 percent, however, is sufficient to pose a threat to drinking water in areas with high pesticide inputs. When the buffer capacity is exceeded, the soil can become a source of chemicals, leaching pollutants into the groundwater. Soil micro-organisms are responsible for the decomposition of organic matter, as well as the transformation of other substances such as sulphates and nitrates. Environmental changes may substantially reduce the capacity of the soil to hold pollutants, thus soil is a key factor in determining the critical load of natural ecosystems.
• Soil provides a habitat for billions of organisms and micro-organisms. It also forms a gene reserve. A decline in soil quality will generally contribute to a decline in biodiversity.
• Soil is a physical medium for the development of infrastructure (such as houses, industrial premises, roads, and recreational and leisure facilities) and for waste disposal. Two percent of the European continent is covered by built areas, ranging from 0.5 percent in Iceland to 12 percent in Hungary, 13 percent in Italy and 14 percent in the Netherlands. A number of countries have taken the view that the best agricultural soils should not be used for building or infrastructure development.
• The ground is a source of raw materials such as clay, gravel, sand and minerals, as well as fuels such as peat. The proportion of land used for opencast mining is estimated at 0.1 percent of the European continent. Mining activities can have a significant impact on the local environment.
• Soil is also a historical medium, concealing archaeological artifacts and palaeontological materials.

Conflicts may arise when different soil functions are in competition. For many centuries, soil functions were maintained without great difficulty. Problems arose at the beginning of the 20th century, when increasing development disrupted the soil’s ecological functions. Settlements and infrastructure expansion, industrial and transport development, waste dumping, mining for raw materials and intensive agriculture all exert pressure on the soil. Soil properties usually deteriorate as a result of human activities, leading to the degradation of one or more of the soil's functions.

A balance needs to be found among all the competing interests and soil use must be harmonised at regional level in order to protect the soil and safeguard its functions.

Soil degradation occurs when human activities reduce the existing or future capacity of the soil to support life. The most severe soil degradation processes are outlined below.

Soil erosion — Erosion refers to the removal of soil material by water or, to a lesser extent, by wind. Soil erosion may be caused by any human activities that expose the soil to the impacts of rain or wind, or that increase the speed or amount of surface runoff water. Farming practices, such as ploughing slopes, removing vegetative soil cover, abandoning terraces, overstocking, poor crop management and rotation, and using heavy machinery that compacts the soil, all contribute to this process. Deforestation and overgrazing are the main causes of severe erosion in many countries. The economic consequences of soil erosion are considerable. Water erosion usually affects crop production by decreasing root depth, removing plant nutrients, eliminating organic matter, and occasionally uprooting plants and trees. Agricultural losses may reach 30 percent of normal yields. On high mountains, soils are predominantly shallow and covered with forest or non-intensive grassland. Due to the growing popularity of winter sports, large areas have been developed into ski runs. The intensive use of slopes results in the physical deterioration of the soil and land compaction, which lead to erosion. Practically all soils on sloping land are vulnerable to erosion, although sandy or silty soils are at particular risk. Other factors, such as the amount of organic matter, infiltration rate, and soil structure and surface, also play an important role alongside external factors such as topography, climate, vegetation and management practices. A wide variety of possible technical solutions (including strip and alley cropping, rotation farming, agro-forestry practices, adjusted stocking levels, the use of cover crops, or the construction of mechanical barriers) can be employed in order to limit erosion. However, other non-technological factors, such as population pressure, social structures, and economic and ecological impacts must also be taken into consideration.
 
Soil acidification — Acidification is a natural process, recently aggravated by human activities through the emission of sulphur and nitrogen compounds from the combustion of fossil fuels and from industrial processes. Fertilisers and soil drainage may also cause acidification. In Western and Central Europe, acidic deposition is the main cause of soil acidification. The main impact of acidification on the environment is the leaching of acidifying compounds from the soil into the surface water and groundwater. Acidification, combined with cations of iron, aluminium, calcium, magnesium and some heavy metals, decreases the soil’s buffering capacity. Sandy soils have lower buffer capacities, thus only a small change in pH may be sufficient to change the soil from a buffering to a polluting agent. There is a risk of heavy metals being released when the pH is very low. Soil acidification and its effects on forests and crops can be counteracted by fertilisation and liming (liming will raise soil pH, but will also have an impact on soil biota that is not necessarily desirable). However, this treatment cannot restore the soil’s buffering capacity, making soil acidification one of the most severe environmental threats in Europe, the full effects of which cannot be reversed.

Past and present economic activities — Economic activities often result in the pollution of the underlying soil where these activities take place. The most common toxic soil pollutants include metals and their compounds, organic chemicals, oils and tars, pesticides, explosive and toxic gases, radioactive materials, biologically active materials, combustible materials, asbestos and other hazardous materials. These substances commonly originate from the disposal of industrial and domestic waste products in designated landfills or uncontrolled dumps.

Soil recovery 

The recovery of the soil's properties is not an easy task:

• In some cases, the soil's properties may return naturally to their normal range of values once the threat is removed — the main question being the amount of time required.
• In other cases, the soil will not return to its original condition but could, under management, be converted into some other desirable state.
• Strategies for dealing with point sources of pollution require both pollution prevention and the remediation of soil and groundwater contamination. Prevention can be focused on reducing industrial emissions and the amount of generated waste, as well as soil and groundwater protection.
• There are various technologies available for treating contaminated land, such as soil excavation, washing and disposal. These methods, however, are extremely expensive. Some new technologies for treating soil pollutants with immobilising additives are more cost-effective.

Clean-up costs are often so high that the only practical approach is for the owner of the polluted property to share the cost with society. At the same time, maximum technical, financial and legislative resources must be directed towards preventing new pollution.

Despite its comparatively small size, the territory of Belarus is characterised by fairly diverse natural conditions and soil formation factors. This diversity is due to the complexity of the terrain, the variety of soil-forming materials, and the significant variability of the climate and vegetation cover. The diversity of natural conditions in the different regions of the country determines the formation of the soil in the respective areas.

• The mosaic of natural and climatic conditions in Belarus gives rise to different soil-forming processes. The most important soils are podzolic soil, sod-podzolic soil and marshy soil. These can occur either in pure form or in various combinations. 
• Thirteen genetic soil types have been identified on the territory of Belarus. The main types are podzolic soil (covering about 2 percent of the territory and found throughout the country, although more commonly in the southern and south-western parts); sod-podzolic soil (used mainly for cultivation, covering 45.1 percent of the territory and found throughout the country), marshy soil (11.5 percent) and floodplain soil (7.2 percent).
• According to the cadastral evaluation of arable soils, Belarus scores an estimated 31.2 points: 46.4 percent of arable land has a fertility rating of between 25 and 35 points; 16.3 percent has a fertility rating of between 20.1 and 25.0 points; and 7.6 percent a rating of 20 points or lower.

The 2006 national report of Belarus on the implementation of the UN Convention to Combat Desertification mentions chemical contamination as one of the factors contributing to land degradation. Chemical contamination is characteristic mainly for cities and their surrounding areas, roadsides, zones affected by waste disposal, agricultural land and industrial sites.

According to the National Action Plan on the Rational Use of Natural Resources and Environmental Protection of the Republic of Belarus 2006–2010, the total area of soil with dangerous levels of contamination in urban areas is estimated at 78,000 hectares; in areas near roads 119,000 hectares; on agricultural land 10,000 hectares; and in areas used for waste disposal 2,500 hectares.

Over a five-year period, in the framework of the National Environmental Monitoring System (NEMS), the accumulation of petroleum products and heavy metals — and, to a lesser extent, sulphates and nitrates — was noted in soil samples from 44 cities in Belarus. Petroleum contamination was characteristic of soils in all surveyed cities. In 50 percent of settlements, the oil content of the soil was five to 15 times higher than the maximum permissible concentration (MPC). Cadmium, zinc and lead were the main pollutants among heavy metals. Cadmium contamination was typical in 72 percent of the surveyed cities, zinc in 77 percent, and lead in 61 percent. There were many instances of contaminant levels being double, or more than double, the MPC, including cadmium (in eight cities), zinc (in 14 cities) and lead (in nine cities). High concentrations of copper were found in four cities. Soil contamination from nickel and manganese was not noted in the surveyed cities. Contamination by sulphates at levels between one and one and a half times the MPC was observed in 39 percent of surveyed cities. Samples from only three cities revealed excess concentrations of nitrates.

In the course of local land monitoring, undertaken as part of the NEMS in 2007, zinc and cadmium were identified as priority pollutants in soil samples taken from industrial areas used for mechanical engineering and metalworking factories, while copper, nickel and chromium were present to a lesser extent. The metal content in samples taken from some sites exceeded MPCs by several orders of magnitude.

Polycyclic aromatic hydrocarbons (PAHs), petroleum products and polychlorinated biphenyls (PCBs) are the main soil pollutants emitted from factories producing fuel and energy, chemicals and petrochemicals. Soil at industrial sites devoted to the production of building materials are contaminated with arsenic. At some sites, arsenic levels are several times higher than normal.

In Belarus, agricultural practices that cause soil contamination include the excessive use of pesticides and mineral fertilisers, which leads to the accumulation of chemicals in the soil, and excessive irrigation with wastewater from livestock farms.

• As pesticides protect a substantial proportion of crops, their use was quickly introduced in agriculture. In Belarus, pesticides are used each year on about 3.5 million hectares of farmland.
• The intensive use of mineral fertilisers has had a positive impact on the agro-chemical properties of the soil. However, it can also result in the accumulation of chemical compounds in soil, plants and water reserves. Nitrates and chlorine are the most dangerous for the environment.

Soil contamination from radioactive materials is due mainly to the testing of atomic and nuclear weapons in the atmosphere and accidents at nuclear power plants. As a result of the 1986 Chernobyl accident, 23 percent of the territory of Belarus was contaminated by radionuclides, thus the problem of radioactive pollutants in the soil is particularly acute across the territory of Belarus.

Strategies to prevent soil contamination are complex and multifaceted. A transition to low-waste and zero-waste technologies should take place in the industrial and energy production sectors. In the agricultural sector, there is a need to introduce effective agronomic and biological pest control methods and low-hazard pesticides; to reduce and hopefully eliminate environmental contaminants in practice; and to employ science-based technologies when using chemical fertilisers.

In terms of erosion, in Grodno region 1.7 percent of arable land is exposed to wind erosion; in Gomel region 1.6 percent; in Minsk region 1.1 percent; and in Brest, Vitebsk and Mogilev regions 1 percent.

Annual humus loss in Belarus is estimated at 180 kg per hectare; annual nitrogen loss at up to 10 kg per hectare; and annual potassium phosphate loss at up to 6 kg per hectare.

The cultivation of row crops could be responsible for the loss of 2 to 3 tonnes of peat per hectare in the Palessie area of Belarus.

The following laws of the Republic of Belarus cover some of the issues related to the use and protection of soil resources:

• The Land Code (1999)
• The Natural Resources Code (1997)
• The Law on the Conservation of the Environment (1992)

Several institutions in Belarus are involved in the study of soil resources:

• The Institute of Soil Science and Agricultural Chemistry of the National Academy of Sciences of Belarus (Minsk): nasb.gov.by/rus/organizations/institutes/inoagro.php
• The Palessie Agrarian Ecological Institute of the National Academy of Sciences of Belarus (Brest): paei.by
• The Department of Soil Science of the Belarusian State Agrarian Academy and Grodno State Agrarian University: www.baa.by/facultet/agroek/kafedra/pochvovedenia
• The Department of Soil Science and Land Information Systems of the Belarusian State University: www.geo.bsu.by/index.php/departments/soil-science.html
• The Department of Agrarian Disciplines of Baranavichy State University: www.barsu.by/