Land Degradation

Introduction

Land degradation is one of the most important global issues because it affects all parts of the world and, more significantly, has severe impacts on agronomic productivity, the environment, food security, and the quality of life. The term land degradation is a relatively new scientific description of an ancient environmental problem that has been in existence probably since humans began to use fire to modify landscapes. Essentially, land degradation refers to natural and anthropogenic processes that significantly decrease the utility or potential utility of the biophysical environment, sometimes leading to loss or change of features of the environment that cannot be replaced. In the context, land degradation results whenever there is a mismatch between land quality and land use.

Discussion

Land degradation is only one of many terms that have been used to describe the process of degradation of the biophysical environment; other standard references include degeneration of the soil, environmental deterioration, exhaustion of land, and desertification. The latter is often used interchangeably with land degradation, although its more appropriate usage is strictly in reference to the process of environmental degeneration that occurs particularly (but not exclusively) in the arid, semiarid, and dry sub humid areas, resulting from various climatic variations and human activities. For example, the semiarid to weakly arid areas of Africa are especially vulnerable to land degradation because they are characterized by fragile soils, localized high population densities, and a low-input form of agriculture. A universally accepted definition of land degradation may not be possible considering the myriad factors thought to be responsible for it. Land is considered degraded when it suffers a loss of intrinsic qualities as a result of one causative factor, to be discussed in the next section, or a combination of natural and human forces that overrun intuitive regeneration and/or restorative management. That is,

Net land degradation = (Natural degrading process + Human interference) - (Natural reproduction + Restorative management).

Many scholars of the environment subscribe to the prevailing view that land degradation can occur in any part of the world irrespective of its climate, topography, or environmental characteristics so long as human demands on the natural resource base coupled with natural forces reach certain critical thresholds. Indeed, all world regions suffer from some degree of land degradation (Tables 1 and 2) that not only threatens the local quality of life but in some cases actually threatens the viability of the affected areas. As shown in Table 1, about 70% of the dry land areas worldwide have been affected by land degradation, with Africa, Asia, and the Americas having the highest percentages of degraded lands. (Blaikie, Brookfield, p. 24)

Causes and Processes of Land Degradation

Although land degradation has been variously attributed to “acts of God” or “acts of peasantry,” many researchers are in agreement that the problem is most widespread in environments that are exploited by humans; hence, human action takes the most blame. However, the main matrix of stability in most terrestrial environments that safeguards the land against degradation is the delicate set of reciprocal ...