In certain regions where mixed farming prevails, the specialization of the farms (with the progressive disappearance of livestock) has brought about uniform methods of land occupation which run counter the environmental functions of farming. For that matter, grasslands and perennial covers have beneficial effects, but their insertion or their maintenance have to be thought out at the territorial scale.

Land-use and vegetation cover have been linked to the nutrient levels (nitrogen, phosphorus) of surface waters in several countries. However, the links generally relate to streams and rivers, or to specific types of standing water, for example shallow lakes in a geologically defined region.

In certain regions where mixed farming prevails, the specialization of the farms (with the progressive disappearance of livestock) has brought about uniform methods of land occupation which run counter the environmental functions of farming. For that matter, grasslands and perennial covers have beneficial effects, but their insertion or their maintenance have to be thought out at the territorial scale.

As data sets of multiple types and scales proliferate, it will be increasingly important to be able to flexibly combine them in ways that retain relevant information. A case in point is Amazonia, a large, data-poor region where most whole-basin data sets are limited to understanding land cover interpreted through a variety of remote sensing techniques and sensors. A growing body of work, however, indicates that the future state of much of Amazonia depends on the land use to which converted areas are put, but land use in the tropics is difficult to assess from remotely sensed data alone.

The Office de la Haute Vallée du Fleuve Niger (OHVN) zone in southern Mali is a small but important agricultural production region. Against a background of environmental degradation including decades of declining rainfall, soil erosion, and human pressure on forest resources, numerous farming communities stand out through the use of improved soil and water management practices that have improved agricultural and environmental conditions. Field surveys conducted in 1998-2001 indicated that environmental and agricultural conditions have improved in the past decade.

The unequal distribution of agricultural land is often cited as a source of inefficiency in agriculture. Previous cross-country studies of agricultural productivity differences, though, have not considered land inequality. This article addresses this issue by using cross-country data on inequality in operational holdings of agricultural land from Deininger and Squire (1998) . In an estimation of an agricultural production function, the Gini coefficient for land holdings is found to have a significant negative relationship with productivity.

In many European mountain regions, natural forest regrowth on abandoned agricultural land and the related consequences for the environment are issues of increasing concern. We developed a spatial statistical model based on multiple geophysical and socio-economic variables to investigate the pattern of natural forest regrowth in the Swiss mountain area between the 1980s and 1990s. Results show that forest regrowth occurred primarily in areas with low temperature sum, intermediate steepness and soil stoniness as well as close to forest edges and relatively close to roads.