Assessment Of Soil Degradation

Assessment Of Soil Degradation

Chapter One

Preface

Background to the Study

mortal conditioning ply tremendous goods on land cover through a variety of land uses. mortal use of land has altered the structure and functioning of the ecosystem( Turner etal., 1994). Land, whether in tropical or temperate regions land is being used for the purpose of growing trees, crops, and creatures for food, as well as structure spots for houses and roads, or for recreational purposes among others( Hartemink etal., 2008).

Encyclopedically, land use/ land cover has changed vastly in the once decades- substantially reflecting the enormous growth in mortal population and their need for food, sanctum and other musts of life. Changing demography and particularly the changing age structure of populations, a high rate of urbanization, and a faster rate of population growth in relation to profitable growth( Braimoh, 2003; Ouedraogo, etal., 2010), are major motorists of environmental change with significant negative impacts on the natural resource base. Demographic change thus constitutes a major motorist of land use/ land cover change( LULCC) Its primary and utmost direct impact is through opening up of new land for husbandry, agreement and infrastructural development, although other extractive conditioning similar as logging and booby-trapping are also significant( FAO, 2003). The world’s population has doubled smce 1960( Hartemink, 2006). The developing world accounts for about 95 of the population growth with sub­ Saharan Africa as the world’s fastest growing region( Hartemink, 2006). The growing population has numerous counteraccusations but utmost of all it requires an increase in agrarian product to meet food demand. This demand can be met by expansion of agrarian land or by intensification of being systems. Clearing of new lands, for whatever purpose has long been common in areas with fleetly growing populations( Kates, 2000; Braimoh, 2003; Ouedraogo, etal., 2010).

Land coffers have been altered by rapid-fire land use and cover changes accelerated by changeable socio- profitable factors including high population growth, rapid-fire urbanization( Fabiyi, 2006), agrarian intensification and government programs( Entwisle etal., 1998; Mather etal., 2000; Braimoh, 2003; Ouedraogo, etal., 2010). mortal pressure upon land coffers and relations between varying climatic characteristics grease changes in land use/ land cover( Hartemink etal., 2008). In the absence of indispensable livelihood openings and proper operation of the terrain, this rapid-fire population growth and urbanization has redounded in environmental declination and resource reduction. Between 1990 and 2000,sub-Saharan Africa lost 52 million hectares of timbers which amounts to a drop of0.8 per time and 56 of the global aggregate. It’s estimated that 60 of the tropical timber areas cleared in Africa as a total between 1990 and 2000 were converted to endless agrarian smallholdings( FAO, 2003).

Rapid Population growth affects the natural resource base through increased demand for food, water, pastoralist land and other essential accoutrements , similar as wood among others, thereby easing encroachment into timbers and woods as well as adding demand for fossil energies and other coffers. The poor or low soil quality base arises due to two major factors. With many exceptions, growth in mortal population have led to a reduction in the per capita land vacuity and a breakdown of the quondam traditional natural free system that used to be the means of replenishing soil fertility. The styles used to restore the fertility of soils and to2sustain agrarian productivity under traditional shifting husbandry have come ineffective, and in some cases, have faded altogether. As high implicit land becomes less available and the pastoral mortal population increases, husbandry is extending into further fragile lands, undermining the natural resource base as well as undermining the continued capability to produce food for the bulging populations. declination of the natural resource base in tum impinges on the livelihoods of all, but particularly pastoral communities. further small growers are forced to work harder, frequently on shrinking granges on borderline land, to maintain ménage inflows.

Soil declination, and in particular the decline of soil chemical fertility, is a major concern in relation to food product and the sustainable operation of land coffers. It also affects land use/ land cover but the spatial and temporal goods of soil fertility change and its commerce with land use/ land cover change remains to be delved .

Land use involves the manner in which the biophysical attributes ofthe land are manipulated and the intent underpinning similar manipulation for which the land is used, whereas land cover implies to the biophysical state of the earth’s face and immediate subsurface including biota, soil, geomorphology, face and groundwater, mortal structures etc( Meyer etal., 1994; Lambin etal., 2003). Land use change implies the conversion of land use due to mortal intervention for colorful purposes similar as husbandry, agreement, transportation, e t c( Williams, 1994; Meyer, 1994; Turner etal., 1995). While land cover change on the other hand, refers to revision of the being land cover or complete conversion of biophysical cover of the land to a new land cover type( Solomon, 2005).

Though people have been using and modifying land to gain food and other rudiments for thousands of times, current rates, extents and intensities of Land use/ land cover change are far lesser than ever in history, performing in unknown changes in ecosystems and environmental processes at original, indigenous and global scales( Lambin etal., 2003).

The area under crop civilization in the world has increased encyclopedically from an estimated 3 00- 400 million ha in 1 700 to 1500-1800 million ha in 1 990, a4.5- to fivefold increase in three centuries and a 50 net increase just in the twentieth century. The area under pasturage increased from around 500 million ha in 1700 to around 3 1 00 million ha in 1990( Ramankutty etal., 2002b). These increases indicate to changes, concurrences or transformations of timbers cover and the metamorphosis of natural champaigns, downs, and downs. timber area dropped from 5000- 6200 million ha in 1 700 to 4300- 5300 million ha in 1 990. Steppes, downs, and champaigns also endured a rapid-fire decline, from around 3200 million ha in 1700 to 1800-2700 million ha in 1990( Ramankutty etal., 2002b)