Update: 08.12.2017

Five tonnes of animal life can live in one hectare of soil.

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The International Union of Soil Sciences (IUSS) is the global union of soil scientists. The objectives of the IUSS are to promote all branches of soil science, and to support all soil scientists across the world in the pursuit of their activities. This website provides information for IUSS members and those interested in soil science.

The 4th International Conference on Land Degradation and Desertification

Cartagena-Murcia, Spain, September 13-17, 2004

This is the 4th International Conference of the Working Group on Land Degradation and Desertification of the International Union of Soil Science. The Group was formed at the first meeting on the theme in 1996 at Adana, Turkey, organized by Dr. Selim Kapur and with the initiative of Dr. Ahmet Mermut. Considerable information on land degradation in the Mediterranean region was generated at this meeting. The Working Group of the IUSS was in response to a growing awareness of this global problem and has one main objective. This is to provide a forum for soil scientists to conduct research and discuss the challenges and needed technologies from a soil’s perspective. The Working Group recognizes the multifarious dimensions and the very strong role of socioeconomic conditions in land degradation and desertification. It is also acutely aware of the historical aspects and the impact of land use and management. All these and other aspects are being addressed by other groups and the whole effort is coordinated by the United Nations Convention to Combat Desertification.

A 2nd Conference was held in Thailand and hosted by the Land Development Department of Thailand. This meeting was held in Khon Kean in 1999 and was organized by Mr. Taweesak Vearasilp. The Conference attracted a number of participants from Asia. The 3rd Conference (ICLD3) was held at Rio de Janeiro in 2001 and organized by Dr.Antonio Ramalho and his colleagues from CNPS-Embrapa (Embrapa Soils), developed an excellent program that attracted 274 participants from 45 countries, particularly from South America, among them 18 keynote lecturers. The Working Group conducted a Symposium on the subject at the 17th World Congress in Bangkok in 2002.

The 4th International Conference on Land Degradation and Desertification

The 4th International Conference on Land Degradation and Desertification

The 4th Conference in Cartagena was organized by Dr. Angel Faz Cano and his colleagues at the Universities of Cartagena and Murcia. Many sponsors contributed financially and through other means to ensure the success of the meeting. The meeting was attended by over 250 participants from 51 countries and they participated in an ambitious program with the following themes:

  • Geographic perspective
  • Historical and archaeological perspectives
  • Linkages with global issues
  • Quantifying land resources stresses
  • Managing land quality
  • Human impact
  • Policy and legal framework
  • Rehabilitation
Mine-waste accumulated since Roman time: a source of heavy metal contamination of soils and aquifers in the Cartagena area.

Mine-waste accumulated since Roman time: a source of heavy metal contamination of soils and aquifers in the Cartagena area.

Land degradation will remain an important global issue for the 21st century because of its adverse impact on agronomic productivity, the environment, and its effect on food security and the quality of life. Productivity impacts of land degradation are due to a decline in land quality on-site where degradation occurs (e.g. erosion) and off-site where sediments are deposited. However, the on-site impacts of land degradation on productivity are easily masked due to use of additional inputs and adoption of improved technology and have led some to question the negative effects of desertification. The relative magnitude of the economic losses due to productivity decline versus the environmental deterioration also has created a debate. Some participants argued that on-site impact of soil erosion and other degradative processes are not severe enough to warrant implementing any action plan at a national or an international level. Land managers (farmers), they argue, should take care of the restorative inputs needed to enhance productivity. Agronomists and soil scientists, on the other hand, argue that land is a non-renewable resource at a human time-scale and some adverse effects of degradative processes on land quality are irreversible e.g. reduction in effective rooting depth. The masking effect of improved technology provides a false sense of security.

The productivity of some lands has declined by 50% due to soil erosion and desertification. Yield reduction in Africa due to past soil erosion may range from 2 to 40%, with a mean loss of 8.2% for the continent. In south Asia, annual loss in productivity is estimated at 36 million tons of cereal equivalent valued at $5,400 million by water erosion, and $1,800 million due to wind erosion. It is estimated that total annual cost of erosion from agriculture in the USA is about $44 billion per year, about $100 per acre of cropland and pasture. On a global scale the annual loss of 75 billion tons of soil costs the world about $400 billion per year, or more than $70 per person per year. There are only about 3% of the global land surface that can be considered as prime or Class I land and this is not to be found in the tropics. Another 8% of land is in Classes II and III. This 11% of land must feed the 6.5 billion people today and the 8.5 billion expected in the year 2020. Desertification is experienced on 33% of the global land surface and affects more than 1 billion people, half of whom live in Africa. There is ample justification for enhanced efforts to address land degradation.

The workshop, through its papers, posters and discussions, concluded that:

  • The International Union of Soil Science must take the leadership to develop guidelines for the assessment and monitoring of land degradation to enable countries to implement national programs;
  • Current knowledge and databases are inadequate to quantify land resource stresses and more research is needed in this area;
  • Implementation of conservation programs and development of strategies requires definitive scientific and technical base with a cadre of well-trained staff and facilities to implement the programs; institutions that traditionally focused on soil survey should expand their curricula to include aspects of land degradation and desertification;
  • Soil remediation techniques are expensive and time-consuming and effectiveness is very uncertain; alternative techniques must be developed to address chemical contamination of soils;
  • The Convention to Combat Desertification (CCD) of the United Nations has not contributed to the alleviation of the problems due to their inability to rally and capitalize on the technical knowledge and experience available; it is recommended that CCD invest more to build up its technical capabilities.

The Chairperson of the IUSS Working Group on Land Degradation and Desertification is Dr. Hari Eswaran. At the 4th Conference, he relinquished the position to the Chairperson of the 5th Conference, Dr. Marcello Pagliai. The 5th Conference will be held in Italy in the year 2007 or 2008. The membership of the Core Committee of the Working Group is:

Past and current Chairperson of the Working Group on Land Degradation and Desertification

Dr. Hari Eswaran (left) and Marcello Pagliai (right)