|Douglas Jr, Clyde|
Submitted to: American Association for the Advancement of Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/1999
Publication Date: N/A
Technical Abstract: Soil erosion from the dryland cropping systems on the Columbia Plateau results predominately (86 %) from low intensity rainfall on frozen soil, snow melt on frozen soil, or rain combined with snowmelt on frozen soil. Within this region, approximately 1.8 million ha planted to winter wheat following summer fallow lose from 22 to 336 ton/ha of topsoil per year. Crop residue management (CRM) is a critical factor in soil erodibility, particularly in winter wheat systems where crops are fall planted and there is limited green cover through the winter. Traditionally, the moldboard plow has been used to plow crop residue into the soil, leaving very little residue on the surface. Chisel plowing leaves more residue than moldboard plowing, but has associated weed and disease problems. Rainfall was simulated onto plots with four CRM methods under frozen and thawing soil conditions. The four CRM methods were moldboard plow, chisel plow, and a mowplow system with two residue levels. The mowplow system consists of mowing standing residue directly ahead of a plow, so that the cut residue can be blown onto the adjacent plowed strip. There were no measurable differences in runoff between the treatments. The chisel plow treatment was the most effective CRM for the prevention of erosion, followed closely by the mowplow at the greater residue level. Under heavy crop residue, the mowplow system can provide levels of surface residue important to decrease soil erodibility winter wheat/summer fallow croplands of the Columbia Plateau.