Submitted to: International Soil Conservation Organization Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 1999
Publication Date: N/A
Technical Abstract: The Pacific Northwest drylands are a unique and valuable agricultural resource because of their deep loess soils and favorable climate. Soil, water, and air quality are threatened, however, by substantial resource degradation that has occurred due to agricultural practices used over the past 120 years. Inversion tillage has accelerated water erosion and tillage-induced soil translocation, and resulted in decreased rooting depth, water holding capacity, organic matter, porosity, infiltration, biological activity, and nutrient availability at eroded surfaces. Over time, depositional surfaces have received subsoil from eroded uplands with markedly poorer soil quality. Use of ammonia fertilizers has promoted soil acidification to levels that adversely impact crop yields, increase soil- borne disease pressure, and decrease nutrient cycling and use. Compaction, water logging, and poor aeration are problematic in poorly drained lowlands. Drier areas of the region are subject to severe wind erosion an associated loss of topsoil and degraded air quality. Reduced tillage and direct seeding offer a means to promote agricultural sustainability by reversing the deterioration of soil, water, and air quality. This presentation will cover causes and effects of soil degradation in the dryland areas of the Pacific Northwest and document efforts to reverse the process.