«Dissertation Zur Erlangung des akademischen Grades Doctor rerum agriculturarum (Dr. rer. agr) eingereicht an der Landwirtschaftlich-Gärtnerischen ...»
City Expansion: In the case of city expansion, most of the green areas around the cities and pri-urban farmland are affected by degradation. Although, this kind of biomass loss is for the settlement of the population, but through this process, agricultural land is reduced, and the pressure on the remaining land is increased to achieve greater production from less land; the intensive use of fertilizers and other chemicals by farmers causes soil contamination and subsurface water contamination. This type of degradation also affects the quantity of the food supply because potentially highly yielding land has been used for non-agricultural (urban/industrial) purposes (Roca 1993: 3); this is an enormous threat for prime agricultural land (Romeo and Ordenes 2004: 197).
Institutions and land degradation: Apart from using the typical approach of blaming natural factors or the lack of cooperation between different land-use stakeholders, land can also be degraded because of inappropriate land institutions, e.g., the land tenure system, poorly defined property rights, or the unequal distribution of land together with insufficient state bureaucracies dealing with the strategies of land and soil conservation (Biot et al. 1995: 30).
Meyer and Turner (1994: 6) have examined several major issues of inquiry in land transformation. They focus on human driving forces such as population, income change, technological change, and institutional, political and cultural change. Unsustainable governance structures are the reason for weak tenure rights and security for smallholder farmers, pastoralists, forest-dependent people, and indigenous people.
2.4 Land Degradation at World Level
Over many years human beings have used land to gain diverse benefits, and many of the methods used to gain those benefits are now being seen as unsustainable, because in many cases they lead to degraded land. About seven billion hectares of the World's land are considered as arable in comparison with a total area of 13.2 billion hectares, with only 1.5 billion hectares being cultivated at present (Massoud 1981: 3). According to the Report of Global Environment Outlook 3, published in 2003, approximately two hundred million hectares of the World, which is equal to more than the United States and Mexico, has been lost to exploitation for agriculture and environmental services because of land degradation.
About thirty four million hectares, which is twenty three percent of the total cultivated area,
are saline and fifty six million hectares, about thirty seven percent, are sodic (Massoud 1981:
Table 2.1 presents the World status of land degradation and clearly illustrates that most of the land is degraded by water and wind erosion, and human involvement through overgrazing, deforestation, and agricultural activities are the common reasons for such erosion.
In general, erosion rates are high in recent years because of the cultivation practices as farmers cultivate many more cash crops instead of pasture crops. The erosion rate in Africa, Europe, and Australia is about five to ten tons per annum on average. Whereas in North, Central, and South America, the rate of erosion is ten to twenty tons annually, in Asia, it is a maximum with thirty tons per year on average (Muir 2010: 4). Rapid increases in population and the burden of this on urban areas are also major causes of land degradation these days (Population Information Report 1997).
In the US, about seventy three percent of pastures are publicly owned, and according to monitoring by the Bureau of Land Management (BLM), at the end of the year 1998, only one third of these pastures were operating satisfactorily, while the remaining two thirds were performing badly (Muir 2010: 2).
In 1996, GACGC introduced a new concept of sixteen syndromes in which natural resources are used insufficiently. Most of these syndromes are related to land degradation. For instance, ‘Sahel Syndrome’ is related to the over-cultivation of marginal land, and ‘Overexploitation Syndrome’ describes the misuse of natural ecosystem. Similarly, if traditional agricultural methods are discarded, then the negative effects on the environment can be studied as ‘Rural Exodus Syndrome’. For urbanization, the damage of land is categorized as ‘Urban Sprawl Syndrome’. This report has tried to focus on global problems, and Sahel syndrome and urban sprawl syndrome are given top priority for resolving the issue of land degradation. It is now a global consensus that the World is being challenged with the problem of land degradation because of deforestation, desertification, and land degradation attributable to urbanization.
Presently, forests represent more than one forth of the total land area as one half of the forest is already lost (Polar regions are excluded). The impact of humans on forests is excessively negative, which has affected the quantity and quality of the remaining forests (Global Forestation 2006). From 1950 to 1980, after World War II, farmland increased as many forests were destroyed. For the increment in irrigated cropland, forests from areas of the size of approximately three hundred and thirty one million hectares were removed (Richards 1990: 163). The same situation has occurred in the Brazilian Amazon where poor farmers have to settle, as they need crop land for their livelihood. Between 1995 and 1998, the government established about one million fifty thousand households that consumed fifty hectares of land, which is approximately forty eight percent of the forest. They produce banana, palm, and rice for one or two years, and when land loses its productivity, they move to another piece of land after cutting down a new part of forest; this is the main reason for deforestation in this region (Butler 2009: 1).
Desertification covers one third of the World's land area. The most obvious impact of desertification is the degradation of 3.3 billion hectares of the total area of rangeland, constituting seventy three percent of the rangeland with a low potential for human and animalcarrying capacity, and a decline in soil fertility and soil structure on about forty seven percent of the dryland areas constituting marginal rain-fed cropland. These degraded irrigated cropland, amounting to thirty percent of the dry land areas, have a huge agricultural potential along with a high population density. Two hundred and fifty million people are suffering from this kind of degradation of land, with one billion people in over one hundred countries being at stake. All these people belong to the poor nations of the World having a weak political setup (UNCCD 2008: 1). About 3.6 billion of the World's useful dryland for agriculture has suffered from erosion and soil degradation, forcing people to leave their farms for jobs in the cities (UNCCD 2008: 1). Recently, Shahid (2006: 17) has emphasized that desertification affects about one sixth of the wworld’s population and one quarter of the total land area of the World. Most of the affected land is in North America (about seventy four percent of the total land) and in Africa, where more than 2.4 million acres of land (seventy three percent of its drylands) are at stake (UNCCD 2008: 1).
Figure 2.1: Areas at Risk of Desertification Source: www.
map.com According to Figure 2.1, regions in Africa are at very high risk, which is attribuTable to overgrazing. Water logging and salinity have also not been tackled tactfully, so that these problems have grown, and the ratio of land degradation has increased in the area. The same situation can be discovered in Australia where people only recently came to settle. Their first remedial measure was in 1930 when they passed their first soil legislation. In Peru, the problem is caused by deforestation. Salinity in the United States and in Mexico is also a great problem for their lands and is reducing their productivity (Dregne 1986: 4).
Urbanization will be a future threat for the World when one million hectares of cropland are converted into roads and highways every year; seventy million people are estimated to need land for their survival including housing and urbanization (Brown 2005: 81). This is not only a threat for crop land but also for forests and other ecosystems, e.g., dryland ecosystem (Dregne 1986: 1). The expansion of cities, mostly covering the countryside or farmland in rural areas, consequently causes a fall in food production, and the remaining land has to bear the load of supplying more food for the larger population. Currently, the World average of available land per capita is forty four people per km2 (FAO 1992). United States (US) is also suffering from this problem, e.g., California an important agricultural state in the US, which was initially an exporter of agricultural products, now produces only forty two percent of its fruit consumption and forty three percent of its vegetable consumption (Osborn 1989). Most part of agricultural land in one of its highly productive valleys, Santa Clara Valley, has been converted into a suburb of large cities. This has a bad effect on the agricultural production of California, probably will find it difficult to produce sufficient food for even its own population.
Because of the increase in the World population, various conflicts between land users have arisen because of the pressure on land. These conflicts cause desertification, deforestation, or soil erosion (USAID 2009). To reclaim this degraded land, proper land management is required. Some decisions relating to land ownership, cultural consideration, and political and economic strategies are necessary for land management and might give rise to sustainable agricultural development. Although, in some places, farmers have successfully reclaimed their land, and communities are now stable and have moved away from the bad effects of land degradation (desertification) with sound growth, most of the information related to the linkage between this degradation and their socio economic and human management is missing.
Although much other information is available, there is a need to organize this information to bridge the gap between what is known and what is not. This link can be established through institutions (Bunning 2002: 1), which include the land tenure system and particularly ownership rights for the sustainability of land (United Nations Population Information Network 1995: 6). In such countries where rangelands are under severe threats, a national action plan against overgrazing can be formulated and strictly implemented. In addition a land-use plan for the mitigation of identified land degradation impacts and measures for soil maintenance can be put into place.
2.4.1 Causes of Land Degradation in Asia Figure 2.1 clearly explains the situation of Asia where most of the areas are at high risk of land degradation. This is the largest continent of the World with a huge population load and has to meet the food demand for its large population. Most of the land in Asia is dryland;1 however Asia together with the Pacific region has been reported to have half (fifty four percent) of the World’s population with only seventeen percent share of the World's land (UN/FAO 1992). Even in this situation, this region of Asia and the Pacific is in a better position than Africa and South and Central America. These regions can fulfill the requirement of the food needed by such a huge population with the production of cereals and other comparative crops. For this purpose, they can use technology and new agricultural practices.
The excessive use of fertilizers and pesticides increases the output but has a negative impact in the form of causing land degradation (UN/FAO 1992). Mainly, degradation occurs through natural hazards, but anthropogenic is also widely observed, e.g., salinity, sodicity, and alkalinity (Blaikie and Brookfield 1986: 4). Because of salinity, ninety percent of the farmland in Abu Dhabi (UAE) has lost its productivity (Henzell 2009). Water Tables in most areas are not up to the standard, and soil has lost its fertility. Fifty percent of Central Asian land is salinized because of the poor drainage system attribuTable to a lack of investment and improper maintenance after independence from the Soviet Government (Ji 2008: 10).