Cumulative Effects of Land Management on Soil and Water Resources: An Overview

Abstract The concept of cumulative effects encompasses a broader spectrum of resources and land uses than has typically been evaluated in research. As management pressures in large drainage basins intensify, pristine areas may be subjected to multiple human activities. These activities are distributed through time and space, and their effects can occur at the location of a particular land use or away from the location. Even though individual land uses may not significantly degrade environmental components such as soil productivity, water quality, or aquatic habitat, the combined effects of several activities may be unacceptable. Theoretically, cumulative effects of land management may also provide benefits to portions of ecosystems, such as increased stream productivity generated by nutrient inputs. Cumulative effects of land management must also be evaluated within the context of natural processes and events, such as large storms, wildfire, geochemical weathering, and vegetation succession. This overview provides examples of cumulative effects of land management and introduces the papers in this issue that were presented at a special symposium held during the American Society of Agronomy meetings in 1989.