|Douglas Jr, Clyde|
Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/1998
Publication Date: N/A
Technical Abstract: In Eastern Oregon and Washington, more than 60 percent of the annual precipitation and 85 percent of the erosion occurs from November through April. Rainfall simulation was used to evaluate runoff and erosion from frozen soils and/or snow on frozen soils in 1996 and 1997. Simulation was performed in two different producers fields (1996:26 percent slope, north aspect; 1997:14 percent slope, west aspect) on a Typic Haploxeroll with 70 percent silt, 18 percent clay and 12 percent sand and 1.2 percent organic matter. Nitrogen was applied in a sub- surface band 13 cm deep with 25 cm between bands uniformly across the plots in field one (73 kg/ha) on September 15, 1995 and field two (90 kg N/ha) on September 25, 1997. Soft white winter wheat (Stephens) was seeded in September 1995, and October, 1996. Tillage and crop residue management treatments were moldboard plow, chisel plow, mow-plow-2100 and mow-plow-6200 kg residue/ha. The mow-plow system is designed to bury weed seeds while leaving crop residues on the soil surface. Rainfall intensity used was 8.7 mm/hr. Runoff samples were taken on February 5 and 7, 1996, and January 15, 17 and 30, 1997, at ten minute intervals for 90 minutes after the start of runoff. Data analysis indicates that runoff nutrient loss was inversely related to the percentage of surface soil covered with crop residue.