ABSTRACT
The Pacific Northwest (PNW) supports significant areas of both irrigated and rainfed agriculture. Conservation tillage in the PNW has been greatly influenced by soil properties affecting and affected by structure and aggregation, and the climatic interactions with these physical properties. Crop and water constraints on conservation tillage on dryland in the PNW are reasonably well understood because many years of research and technology transfer have identified problems and provided solutions or alternative approaches to most of them. The PNW has promoted conservation tillage more successfully than some regions because of the aggressive manner in which the technology was developed and spread in the Solutions to Environmental and Economic Problems (STEEP) program. The STEEP program initially had five research objectives: development of conservation tillage and plant management systems, plant breeding to suit conservation tillage, pest management for conservation tillage, improved erosion and runoff prediction, and evaluation of soil conservation economics and socioeconomics.
