Land Degradation Processes - Essay Example

How land management practices can either exacerbate or mitigate land degradation processes which lead to wind erosion Introduction Land degradation designate permanent or temporary long-range decline in ecosystem function and productivity capacity. It can also be termed as destruction in health of terrestrial ecosystem and therefore affecting the linked ecosystem resilience, biodiversity, and natural ecological processes. Globally, about 20 percent of cultivated lands, 30 percent of forests and 10 percent of grasslands are experiencing land degradation that affects almost 1.5 billion persons. Land degradation will continue to be a vital international issue for the 21st century because of its adverse consequences on agro economic production, the milieu and its results on quality of life and food safety. Output results of land deprivation are as a result of reduction in land quality where degradation takes place for instance wind and water erosion and off sites where sediments are deposited. Some of these effects of land degradation on production are as a result of adoption of enhanced technology and supplementary inputs which have made natives to question the harmful impacts of desertification. Land degradation can be as a result of land management practices which can either increase or lessen land degradation processes. Different key processes of land degradation consist of erosion by wind or water, physical degradation and chemical degradation. Some lands are influenced by more than one process of wind and water erosion, Stalinization and compaction. Wind erosion can result to loss of top fertile soil as the consistent dislodgment of top fertile soil and selective elimination of fine particles. It is extensive particularly in arid and semiarid climates. Wind erosion can also result to land deformation which leads to deflation hollows and dunes. Wind erosion Wind erosion is a severe crisis in various parts of the globe. Wind carries away the top fertile soil, causes air pollution, lessens seedling survival, and creates desert landscapes and forms. It is normally worse in semi arid and arid areas compared to sub humid climates as these areas are associated with dry, loose and finely divided soil, large fields, smooth soil surface with no vegetation cover, and strong winds. Arid land consists of almost one third of global total land area and is inhibited by about one sixth of the global population. Some of the parts vulnerable to wind erosion include: North Africa, Australia, eastern and southern Asia, Siberia plain, South America, and the arid and semi arid portions of North America. Wind erosion can be prevented or reduced through alleviating erodible surface with different materials, creating a cloddy rough surface, reducing the distance of wind travels on unprotected field with strip crops and barriers such as wind breaks, and maintaining adequate vegetation cover. Land management practices Agricultural practices such as how the land is tilled and how herbicides and pesticides are used is a major source of deposit in surface water run off but the degree to which crop growing practices serve as a non point source of effluence is a role of how agricultural land is dealt with. Farmers may use land management practices that increase soil moisture, and control erosion. These methods are referred to as best management practices and consist of reforestation, conservation agriculture, agro forestry, integrated soil fertility management, improved rangeland management, strip cropping, crop rotation, contour farming, and development of grassed waterways and field borders. Some of these land management practices can either aggravate or alleviate land degradation processes that lead to wind erosion. This especially occurs in arid and semiarid areas which are associated with loose and finely divided soil, large fields, smooth soil surface with no vegetation cover, and strong winds. These are major characteristics of desertification. Reforestation and forestation as a land management practice Reforestation is planting of new trees in formerly forested areas while forestation is planting of trees in land that has not been categorized as forest. Reforestation and forestation includes windbreaks, shelterbelts and woodlots. These land management practices can be used to conserve soil quality and quantity. Most lands in arid and semi arid areas have been degraded by human activities resulting to desertification. In most cases the problem of desertification is caused by deforestation, over cultivation, overgrazing, water impoundment, and global climate change. Desertification results to decreased biodiversity and reduced productivity capacity. Sustainable land management practice requires that a fresh tree be planted for every one that is cut down by fuel wood gathering, logging, or land clearing activities. At the international level, nevertheless, it is required that, in order to mitigate wind erosion through forestation and reforestation, thus reducing desertification the number of fresh trees planted every year be more than the number of trees lost in the prior year through deforestation. Amplified tree cover provides windbreaks reducing soil erosion by wind. The fundamental objective of reforestation is to create forests, with the goal of restoring the economic and environmental benefits they supply but they also offer an affluence of social benefits. The natural benefits of trees is that their roots serve as an widespread net that seize the soil in place and therefore preventing or reducing extreme soil erosion and its nutrients. Windbreaks – lows of shrubs and trees suitably located can direct, slow and block winds and this has many benefits to the land owners. The amount of soil erosion that occurs depends on the speed of the wind and the profusion of plant life available in the land. Trees prevent how heavy rains beat the land thereby making the top soil loose and they also prevent these soils from drying up fast which make them easier to be carried away by wind. Trees reduce wind speed and this depends on the density, height, width, and shape of the wind break. Windbreaks can reduce soil erosion by restructuring wind speed across open ground. As a result, reforestation and forestation can help mitigate land degradation processes that lead to wind erosion. However, they do not provide best management practices for reducing soil erosion by wind neither can they completely eliminate drifting soil problems. They serve as supporting practice as part of the wind erosion management. Agro forestry as a land management practice Agro forestry is a set of land use practices that involve deliberate mixture of agricultural crops, trees on the same land control unit in some sort of temporal sequence or spatial array. Cultivating trees together with livestock and crops is a prehistoric practice. Nevertheless various factors have resulted to an increasing interest in agro forestry ever since 1970s for instance increased tropical deforestation, worsening economic conditions in most parts of developing nations, land degradation, intercropping and the environment. The key agro forestry practices incorporate improved fallows, alley cropping, farm woodlots, Silvopasture, riparian forest buffers fodder banks, windbreaks, shelterbelts, plantation combinations and orchards. Agro forestry protects crops and livestock from severe effects of wind, conserves and protects natural resources through mitigation of non point source pollution, and soil erosion control. Alley cropping is the planting of shrubs and trees in several rows and growing crops in the alley ways amid the tree rows. Alley cropping lessens wind erosion by planting trees and shrubs close and vertical to erosive winds. Silvopasture is the combination of livestock and trees in a well managed practice. The effects of agro forestry in mitigating land degradation processes that lead to wind erosion is the same as that of reforestation and forestation. Trees prevent how heavy rains beat the land thereby making the top soil loose and they also prevent these soils from drying up fast which make them easier to be carried away by wind. When practicing, agro forestry, it is important to take caution as this process can also lead to exacerbation of land degradation processes that lead to wind erosion. For instance the practice can result to over cultivation and overgrazing in circumstances where livestock are left to graze in natural woodlands. Mulching and crop residues as land management practices Mulching is another land management practice that involves placing a protective cove (mulch) over the soil to reduce erosion, retain moisture, suppress weed growth, and provide nutrients to plants. Various mulch materials include: organic residues, compost, rubber mulch, and plastic mulch. Mulching is an efficient method for reducing erosion damage increase. Wind erosion can be restricted by mulching with manure or other materials. Almost 2,300 to 2,500 pounds per acre of plant deposit is required to manage land which have substantial wind erosion. The mulch can be spread by manure spreader or hands. A mulch trader assists in anchoring and in spreading the mulch evenly. To make mulching effective in the control of wind erosion, the residue should be anchored perpendicular to the prevailing winds. Mulching improves soil roughness and helps to hold soil together through the anchoring of the mulch therefore reducing wind erosion. Pebble mulch have two roles in controlling wind erosion: first of all it can prevent soil from eroding by wind; and secondly, it can entrap dust that is carried by wind. Strip cropping as a land management practice Strip farming is a farming method used when a slope is too long or steep or when other farming methods might not reduce erosion of soil. Strip farming interchanges strips of intimately sown crops e.g. wheat, hay with strips of row crops e.g. cotton, corn or Soya beans. This farming method prevents soil erosion by generating natural dams for water therefore assisting in the preservation of soil strength. Strip farming can also be defined as a method of dry farming practiced in Great Plains of the United States. The land is left fallow in order to accumulate moisture. The planted land and the fallows are structured in parallel along thin strips that are slanting normal to the existing wind so as to reduce erosion of soil by wind in the uncovered fields. Strip farming assists in reducing wind erosion by anchoring soil to the roots of crops therefore preventing it from being carried away. Strip cropping is an effective method in controlling wind erosion. The strips width usually depends on type of soil, strip bearing in relation to the erosive wind speed and wind direction. For instance, sandy light soils require narrower strips. Conclusion Output results of land deprivation are as a result of reduction in land quality where degradation takes place for instance wind and water erosion and off sites where sediments are deposited. In order for land owners to reduce land degradation, they should take measures to combat land degradation processes such as wind and water erosion. Wind erosion management is practiced out on two ways: first lessening wind-speed at ground level and rising soil structure, thus enhancing top soil resistance to wind. Wind erosion supposes considerable proportions only when the wind takes a load of soil that bombard the uncovered soil surface. Fine top fertile soil is carried away by wind and this can be mitigated by various land management practices such as mulching, agro forestry, strip cropping, and reforestation among others. These practices assist in lessening fine particles in the land surface, improvement of soil structure, and roughness and cohesion. The control methods are similar and they include wind breaks, maintaining deposit cover on the soil surface, coarse tillage, hedges, and course tillage among others. Although each one technique to manage wind erosion has an advantage and purpose, setting up and preserving vegetative cover, when practical, continues to be the most excellent guard against wind erosion. On the other hand, that becomes a complex challenge as demands boost to use crop residues for livestock feed and fuel for food preparation. Keep in mind that, avoidance is the best technique of managing wind erosion. The superlative prevention is retaining continuous shielding cover of crop remains or cultivating plants on the soil surface. Most of these land management practices assist in mitigating rather than worsening the land degradation processes. References Baker, et al. 1996. No-tillage Seeding, Science and Practice. CAB International, Wallingford, Oxon, UK. Bellarby, J. et al. 2008. Cooling Farming: Climate Impacts of Agriculture and Mitigation Potential. Campaign for Sustainable Agriculture. Greenpeace, Aberdeen, UK. Borrini-Feyerabend, G. et al. 2004. Sharing Power. Learning by doing in co-management of natural resources throughout the world. IIED and IUCN.CEESP/CMWG, Tehran. Brown, S. et al. 2000. Project-Based Activities. In: Watson, R.T. et al (Eds.), Land Use, Land-use Change, and Forestry, A Special Report of the Intergovernmental Panel on Climate Change. 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