| Popis: |
The Pacific Northwest (PNW) supports significant areas of both irrigated and rainfed agriculture. This bimodality is also impacted by the diversity of crop and animal agriculture it supports. Drilled grain and pulse crops, row crops, vegetable and horticultural crops, grass sod, and perennial alfalfa (Medicago saliva L.) hay are among the choices that can appear in a farm's cropping system. Developing soil management practices and tillage systems to accommodate such diversity has been a challenge to soil conservationists. To date most research published from the region has concentrated on small grain production in the dryland areas. Another smaller body of literature has dealt with conservation tillage of irrigated field crops. The potential for development of conservation tillage in the PNW derives from the region-wide severity of erosion in both dryland and irrigated agriculture. Residue management has been the essential element of the tillage systems in both cases. Although preserving crop residues at the soil surface is a key strategy, conservation tillage in the PNW has embraced other practices as well. Furthermore, greater recognition of the extent and severity of erosion under irrigated conditions is warranted, and research on erosion and conservation tillage for irrigated systems should be a high priority. |
