A multi-disciplinary research with integration of the theory and methods of climatic change and history was carried out in the southern Loess Plateau of China. High-resolution soil-sedimentary data define an abruptly increased climatic aridity at 3100 a B.P. on the southern Loess Plateau. It was caused by a shift from the dominance of the maritime monsoon to the continental monsoon in the East Asia. The marked aridity induced a considerable deterioration of environment and degradation of land resources.

The total area of the Arab Region is about 14·2 million km2, 90% of it lies within arid, semi-arid and dry sub-humid areas. The area is characterized by harsh environment, fragile ecosystems and limited water resources and arable lands. Throughout its long history these lands were the main source of grain and animal production. By the end of this century and in spite of the national, regional and international efforts to combat desertification and mitigate the effect of drought and desiccation, desertification is still one of the major environmental problems in the Arab Region.

Land degradation cannot be judged independently of its spatial, temporal, economic, environmental and cultural context. Evaluations are therefore almost infinitely variable and very dynamic. These observations are examined in two contexts, first in two case studies. One, from the southern Levant, makes use of a long and well-documented history of environmental assessment that varied greatly between communities. The other, from contemporary Niger, shows finer scale differences among villagers.

There has been an increased interest in the use of vegetative barriers in acid-infertile upland management systems in Southeast Asia. This paper analyses the experimental designs and policies in early-1990s of using vetiver grass barriers (Vetiveria zizanioides L.) in microwatersheds with short-rotation tree plantations in Vinh Phu Province, Vietnam. Four different mixed tree-vetiver models on degraded Ferric-Plinthic Acrisols are discussed.

This paper examines the effectiveness of European Union (EU) agroforestry programmes in reversing land degradation processes in the Mação region of central Portugal. Since the 1980s, the region has experienced severe forest fires, which have had serious consequences for the local ecosystem in terms of land degradation processes and changes in the hydrological cycle. In an attempt to reverse this situation, agroforestry programmes and aid schemes have been introduced to improve land management practices and increase the forest area and stabilize soil.

Soil variability is often seen as problematic in land degradation studies in terms of sampling effort, data interpretation and for the extrapolation of results to other areas or time periods. Examples are given from land degradation research undertaken in central Spain which demonstrate some of these problems associated with soil variability. Geostatistics is presented as a useful tool for quantifying soil variability and in particular the variogram for interpreting and understanding spatial patterns.

Adverse environmental impacts of human activities are the main causes of soil degradation in the desert of Kuwait in general, and in Kabd area in particular. In this study, assessment of soil degradation in open and protected sites has been carried out using field measurements and laboratory investigations. The overall status of vegetation is nearly twice as low in vegetation cover in the open sites than in the protected ones due to overgrazing and off-road transport.

Amidst growing concerns about farmlands conservation, this paper examines the status of farmlands in two mountain watersheds ‘with’ and ‘without’ external intervention, located in the western hills of Nepal. Information was obtained from a household survey and group discussions conducted during April to September 1999. The severity of soil erosion from farmers' perspectives, density of landslides, soil nutrient balance and change in crop yield have been adopted as indicators of the status of the land.

Since the 1970s, federal policies promoting migration and encouraging agricultural development of large farms, logging, and ranching have led to the deforestation of vast areas of the Amazon rainforest.Though these policies have largely been replaced, deforestation continues. What effects do current macroeconomic and regional policies and events have on deforestation and on the well-being of settlers on the agricultural frontier?