Soil Degradation
Introduction
Soil is one of the major resources that are precious. The loss of it through erosion like wind or water is among the major forms of land degradation in Australia (ACIAR, 2005). It is through this form of land degradation that the means of producing food is limited.
Soil erosion is a natural process that has taken place for a long time. Human doings more deforestation and agriculture, however have elevated that rate of soil degradation. This is since they are inclined to eliminating the protective vegetation and drop to lower limits the sustainability of the soil. This human action is attributed to elevating the speed at which soil is degraded.
Soil erosion is natural process in the landscape of Australia, however, from the time the Europeans settled, altering the use of the land and management tendencies have elevated this process. The condition for the soil has dropped by vegetation removal, grazing, cultivation, application of exotic flora and fauna as well as the application of fertilizes. Soil erosion is a great problem which has brought about issues with agricultural control operation.
Soil erosion takes place when the top layer of soil is carried away from one location to another. Regions that are attributed to agriculture practices are connected to having a high rate of soil erosion than regions that are native with vegetation. Cases of regions that report a lot of wind and rain offer land a higher probability of the soil being carried away. The impact brought about by climate change like drier climate and high and severe weather cases has a higher chance of elevating soil erosion.
Current Situation
It is hard to estimate the actual soil that is lost by erosion, so taking to fact the regions that are at a higher risk of experiencing, they are applied as basis of getting a better understanding of the situation. Soil that are of higher risk of being eroded are mostly sandy in nature, found in regions that are of limited rain and are left open to extended time of dry weather.
There are approximately 10.4 million hectares of land found in the southern part of Australia and approximately 6 million hectares, which is 58% that susceptible to erosion. Of this, approximately 21% has a moderate to a higher susceptibility to being eroded by wind because of sandy soil and high proximity. Most this places are found in Eyre Penisula, south and northern part of Yorke areas. Approximately 3.6 million hectares are attributed as being moderate to low vulnerability to erosion by wind.
In the southern part of Australia, about 1.2 million hectares are without agriculture and are attributed to moderate to high chance of being eroded by water. The northern part and Yorke areas of Australia have the biggest chunk of land to be eroded by water. This is connected to the type of soil and sloppiness of land. An additional 1.7 million hectares have a moderate susceptibility to being eroded by water.
Impact of Soil Erosion
Soil erosion affects the health of soil as well as its production in a number of ways. The implication in regard to Australia is wide and certain regions still experience this implication even with a number of practices to control this.
Loss of Soil
The formation of soil is quite gradual and may take a lot of time for it form; approximately 14 t/ha in 100 years. It is just a limited size of erosion that is needed to surpass this rate of formation (Evans, 1992, 82-91). In Australia agriculture typical loss may be increased to 50 t/ha for each year from a bare fallow, 8 t/ha in every year for a crop and 0.24 t/ha in pasture. The erosion of soil brings about the taking away of the top layer of soil, hence leaving open sub-soils that need cautious management.
Loss of Organic Matter and Nutrients
A long period of a drop in productivity arises from the loss of fine clay and organic matter. The taking away of small sizes of top layer of soil brings about the loss of organic nitrogen among other nutrients from the profile of soil and lowers the production of crops. The production are affected when the soil are eliminated from pastures, as organic nutrients get concerted in higher few millimeters of the soil structure in uncultivated soils. The taking away of the top soil brings about instability in the model of the soil resulting to an extended degradation and a drop in the operability of the soil because of soil biota. The lack of organic matter in soil in the 2mm part of the top soil may result to 5% loss of production in subsequent wheat crop.
Plant Health
The loss of the top layer of soil brings about the loss of small-seeded vegetation that lead to a limited density of plant, on the other hand, the loose soil may bring about sandblasting effect from being eroded by wind in the immature and tender crops. The loss of soil may bring about limited depth of soil; drop in the capacity of soil to retain water and nutrients and reducing the availability of root survey, leading to a decline in root and plant vitality. The deposition of vegetation may conceal them and limit the production.
Environmental Impacts
The decline in soil degradation by erosion and run off has a significant effect in the quality of water as the runoff normally is composed of sediments, nutrients, chemicals among others. The erosion of soil by water is a significant procedure that brings bout sedimentation, possible eutrophication of water reservoirs and paths and in severe instances may result to the death of aquatic animals.
Farm Management
When soil erosion takes place, there results the formation of gullies, this limits the trafficability of paddocks and impacts the lack of time for operations to take place (Lumb, n.d). On the other hand, the deposition of the soil may conceal fences or bring them down hence bringing about the reduction of farm infrastructure. Any attempt of putting up a farm infrastructure is at risk of being destroyed again leading to the loss of a lot of expensive structures.
Practices to Limit Soil Erosion
In the initial time, a number of practices were applied to control soil erosion. These practices were based on shifting and creation of terraces of varied forms, more so in Australia and United States. People did plant along the contour and strip cropping was applied. Currently, conservation tillage is applied in Australia and is advanced all over the world by commercial companies and United Nation’s Food and Agricultural Organization. With the advancement of technology, there have arisen a number of practices that are connected to stabilizing the top layer; these practices are currently being advanced.
With the advancement of technology that re targeted at stabilizing the top soil layer and aggregates have been applied, more so in the 90s and are being further advanced currently. This is more so for countries like Australia where crops are grown for commercial purpose; as part of the economy. Here shrubs and trees are grown close to each other. This is a form of sustainable farming that is attributed as being sustainable (Manguerra, et al, 2010). The soil degradation on the plots is limited when compared to land that is cultivated. Australia is common with forest burns that results due to human activities, this leaves the land bare heightening the risk that of land being exposed to soil erosion.
Terrance agriculture is being applied in a number of countries globally. This method was initially applied in reaction to the need of land like cultivation and irrigation. Though now it is being used for reducing the erosion of soil.
Sustainability of Practices to limit Soil Erosion
This section it will address the sustainability of practices to reduce soil erosion on the basis of soil conservation and environment as well as economic and social-political sustainability.
Grazing Land
The most sustainable method to reduce soil erosion is to let the land be limited of grazing intensity. In countries that soil erosion of grazed land takes place; for instance Australia, there is the creation of spillways and pools to hinder an extensive gullying. Animals and more so sheep brought about bare land as well as intensely grazed the sward leading to an immediate saturation of soil in winter. The sediments carried away were as a result of widening of the gullies.
Overgrazed land may pick up with permanent vegetation that controls erosion with animals being kept from the land. In countries like England and Australia, soil or vegetation landscapes have dropped the erosion of soil by 30% hence vegetation cover (Armstrong, 1992, 24-26). With better management of the land and effectively using government funds, the farm is seen as being economically feasible.
Research has to be done to ascertain the grazing moderation limit which would bring about bare soil. This may be more effective through monitoring grazing and the effects in the land. Rules and regulations have to be put in place so as to make the stocking levels feasible economically. These grazing periods have been grounded on rotational stocking method with keen consideration that trampling does not lead to soil that is bare as well as gullies.
Cultivated Land
Barriers to water flow and wind blow
In a number of less advanced countries, a number of methods have been formed so as to hold water that goes on land so that it passes through the soil as opposed to running off. If the barricades are close, the runoff does not get that high speed to go into the land, however particles may be taken by wash. Terraces that built lowly, trenches and ridges may reduce soil erosion, however higher benefit results from improved crop production through trapping rain (Evan, 2006). The soil particles are trapped in the barriers leading to high depth of soil and terraces formed while crop production results.
Grass, trees and intercropping in the contour are barriers to water flow and trim the carrying away of the top soil layer. These methods may not be applied by farmers due to limited finances. The Vetiver grass has been advanced so as to bring about water flow in warm countries like Australia. This is more connected to the monetary and socio-political aspect than a failure of soil conservation methods.
Barriers to control wind erosion like trees or grass have been assesses and advanced though they may not be applied where needed. This is not due to their ineffectiveness but the lack of financial viability. This leads to the allocation of financial kitties or government subsidiaries.
Better Land Management
Land is protected when it is integrated in crop rotation; this hence limits the erosion of soil. The structure of the soil is advanced and when ploughing is done again, more so if the land is under grassed for 3 years, for the period that soil is resistant to being eroded.
The planting of trees or grass on susceptible slopes and interspersing in food crops will lead to a reduction of soil being degraded. The inclusion of manure into the soil structure also leads to an improvement of soil framework as well as cutting down on soil being eroded as well as loss of phosphorus.
Conclusion
In a number of countries agricultural models, sustainable methods have been developed to reduce soil erosion. Though in regions where indigenous vegetation is applied and population is limited, these sustainable processes are not applied as financial, social and political aspects are more considered to environmental desires. Farmers have to be more considered of the future implications of erosion on crop production and the implications of an eroded land on the environment.
It is not hard to come up with measures to safeguard soil form erosion. What is hard I to convince farmers to apply practices to do the same. Short term strategies may over rule actions that bring about long term advantages for farmers to consume and make money from selling their produce and to elevate their standard of living. Hence the devising of strategies that lead to an economical and socio-political method will make it possible for farmers to acquire the soil protecting acts and will prevail over financial and cultural hindrances. Such methods have to bring about financial return so as to not just safeguard the soil but to go on farming so as to elevate the living standard.
References
ACIAR, 2005, Final report: Integrated watershed management for sustainable soil and water resources management of the Inabanga watershed, Bohol Island, Philippines (LWR/2001/003). Australian Centre for International Agricultural Research, Canberra.
Armstrong J. Whiteheads, 1992, International Soil Conservation Organisation, ISCO Conference Southern Tour. 7th ISCO Conference; 24–26, Sydney, Australia.
Evan, R. 2006, Sustainable practices to limit soil erosion: a review and discussion, CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 2006 1, No. 030.
Evans R. 1992, Assessing erosion in England and Wales. In: Haskins PG, Murphy BM, editors. People protecting their land, Volume 1. Proceedings of the 7th ISCO Conference; 1992 Sept 27–30; Sydney, Australia. Sydney: International Soil Conservation Organization; p. 82–91.
Lumb, M., n.d, Land Degradation, The Australian Collaboration: A Collaboration of National Community Organisations, acquired from www.australiancollaboration.com.au
Manguerra, J., Margate, D, and Bavor, J., 2010, Soil erosion as an indicator of agricultural sustainability in tropical watersheds, acquired from http://www.iuss.org/19th%20WCSS/Symposium/pdf/0095.pdf