Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 1996
Publication Date: N/A
Technical Abstract: Soil quality can be defined in terms of three sets of variables which are related to: 1) functional integrity, 2) resistance to disturbance, or inertia, and 3) resilience, or the capacity of the soil to recover functional integrity following disturbance. Functional integrity, resistance, and resilience all vary as a function of processes which vary at different spatial scales; assessment of all three can be improved by accounting for this spatial variability and scale. However, few sampling and analysis approaches for assessing soil quality currently utilize spatial information. The Desertification Response Unit (DRU) methodology was developed in Europe as part of an effort to model processes of land degradation and desertification. The DRU methodology emphasizes landscape position and the potential for interactions and linkages between units at different spatial and temporal scales. It is based on assessing key processes operating at scales ranging from the patch or micro-site to the watershed, and combines static site characteristics at each scale with land surface and vegetation patterns to yield estimates of system resistance and resilience. A preliminary application of the methodology to the assessment of soil quality in rangeland ecosystems for SE Spain suggests that 1) sampling points should be selected to represent key landscape positions within watersheds, 2) measurements should be stratified by cover type, and 3) small-scale changes in soil quality are reflected in long-term dynamics at larger scales.