High Residue Farming In the Treasure Valley of Oregon and Idaho.

The Malheur and Owyhee Watersheds are located in the southeastern Oregon where intensive tillage has been a normal way of life in the irrigated sections. Malheur County currently has 142,000 acres of heavily tilled, irrigated row crops.  The current tillage practiced by farmers in the county result in five – ten passes with ground disturbance equipment to produce onions, potatoes, sugarbeets, corn, wheat, dry edible beans and other seed crops. The result of this heavy tillage in the mineral soils of Malheur county causes increased soil erosion from both wind and water movement,  break down of soil organic matter and soil ped structure.  The water movement loads streams with soluable phosphorus and the soil movement increases sorbed phosphorus  movement off of the fields into streams and rivers.

Some areas of the county are moving to center pivot irrigation, which has decreased, and will continue to decrease, water runoff and nutrient movement off of agriculture land.  The Malheur Watershed Council, Owyhee Watershed Council and the Malheur SWCD have made great strides moving towards sprinkler irrigation, which opens the way for two new methods to decrease water and nutrient runoff.

The two proposed methods will reduce soil disturbance in these watersheds and maximize residue cover.  The first method is strip tillage, a method under row crop production where a hard pan can be taken out and a seed bed prepared in one pass.  Strip tillage reduces the area tilled and decreases the number of passes with different equipment.  Strip tillage tills an area about six to nine inches wide where the seed will be placed.  Fertilizer is often incorporated below where the seed will be placed at time of strip tillage, which will decrease phosphorous losses.  Strip tillage will be done in the fall to allow the soil to settle, to increase early spring soil moisture evaporation and increase soil temperature in the top two inches for spring planted row crops.   

The second method is direct seeding or no-till planting.  Here, the only pass will be using a no-till drill, which is specially designed to allow seeding into the firm soil after the previous crop.  The challenge with drilling this way is the tremendous amount of residue that is left behind certain crops.  Both of these practices will be primarily aimed at acres that currently have sprinkler irrigation.  Sprinker irrigation, which saves irrigation water and reduces soil erosion, is rapidly increasing in this area.  Since it costs more to sprinkler irrigate, methods to decrease the cost of production are needed to stay competitive with furrow irrigation.  Both, direct seeding and strip tillage, are methods to continue encouraging the adoption of sprinklers in this area.