SOIL EROSION AND CONSERVATION THIRD EDITION docx

[...]... traditional soil conservation measures, incentives for soil conservation and community approaches to land care The sections on gully erosion, the mechanics of wind erosion, the dynamic nature of soil erodibility, the effects of vegetation on wind erosion and mass movement, economic evaluation of erosion control, the use of geotextiles and the use of legislative instruments in promoting soil conservation. .. from the effects of erosion both on- and off-site On-site effects are particularly important on agricultural land where the redistribution of soil within a field, the loss of soil from a field, the breakdown of soil structure and the decline in organic matter and nutrient result in a reduction of cultivable soil depth and a decline in soil fertility Erosion also reduces available soil moisture, resulting... atmosphere Erosion control has the potential to sequester carbon as well as restoring degraded soils and improving water quality Since the second edition of Soil Erosion and Conservation was published in 1995, soil erosion has assumed even greater importance because of the higher priority now being given to the environmental issues associated with sediment This revised edition recognizes more strongly that erosion. .. gullies and rivers A distinction is commonly made for water erosion between rill erosion and erosion on the land between the rills by the combined action of raindrop impact and overland flow This is termed interrill erosion To these agents that act externally, picking up material from and carrying it over the ground surface, should be added transport by mass movements such as soil flows, slides and creep,... of the erosion and that 92 per cent of the soil loss occurred in the years when the land was under maize Extreme events may also produce landscape features that are both dramatic and long lasting A slow-moving equatorial storm deposited 631 mm of rain on 28 December 1926 and 1194 mm between 26 and 29 December in the Kuantan area of Malaysia, resulting in extensive gully erosion and numerous landslides... century and again in the late eighteenth century, these sediments were cut through by gullies, up to 5 m deep Whenever land was taken out of cultivation and reverted to forest, erosion rates were very low and the gullies were infilled These historical studies indicate the complex nature of soil erosion Although erosion is a natural process and, therefore, naturally variable with climate, soils and topography,... wetting and drying, freezing and thawing and frost action, and biochemical Soil is disturbed by tillage operations and by the trampling of people and livestock Running water and wind are further contributors to the detachment of soil particles All these processes loosen the soil so that it is easily removed by the agents of transport The transporting agents comprise those that act areally and contribute... Africa but also on the margins of the savanna lands in West Africa, Brazil and southern China Within relatively small areas, rainfall characteristics are reasonably uniform and erosion varies spatially in relation to soils, slopes and land use Boardman (1990) found that between 1982 and 1987 in the area between Brighton and Lewes in the South Downs, England, most erosion occurred in fields on the sides of...Preface Soil erosion is a hazard traditionally associated with agriculture in tropical and semi-arid areas and is important for its long-term effects on soil productivity and sustainable agriculture It is, however, a problem of wider significance occurring additionally on land devoted to forestry, transport and recreation Erosion also leads to environmental damage through sedimentation, pollution and increased... Sediment is also a pollutant in its own right and, through the chemicals adsorbed to it, can increase the levels of nitrogen and phosphorus in water bodies and result in eutrophication Erosion leads to the breakdown of soil aggregates and clods into their primary particles of clay, silt and sand Through this process, the carbon that is held within the clays and the soil organic content is released into the . restoring degraded soils and improving water quality. Since the second edition of Soil Erosion and Conservation was published in 1995, soil erosion has assumed. SOIL EROSION AND CONSERVATION MSEPR 11/19/04 02:49 PM Page i THIRD EDITION R. P. C. Morgan National Soil Resources Institute, Cranfield University SOIL