Submitted to: Columbia Basin Agricultural Research Annual Report
Publication Type: Experiment Station
Publication Acceptance Date: 4/1/2004
Publication Date: 6/8/2004
Citation: Williams, J.D., Wuest, S.B., Schillinger, W.F., Gollany, H.T. 2004. Rotary subsoiling to reduce erosion and improve infiltration in newly planted winter wheat after summer fallow. IN: Special Report 1054, 2004 Columbia Basin Agricultural Research Center Annual Report. Oregon State University, 8 june 2004, Adams, OR. Interpretive Summary: Subsoiling is the practice of ripping continuous open channels or creating pits using a rotary subsoiler to penetrate plow-pans for the purpose of improving root penetration of, and water infiltration into the soil profile. When water infiltrates into the soil profile, it becomes soil water and contributes to crop production, and it does not runoff and carry top soil from a field. Data for this experiment was collected during six years of the seven-year period between 1996 through 2003. The rotary subsoiler created 16-inch deep pit with a 1.0-gallon capacity every 7.5 ft2. Runoff and erosion were not recorded at any location because of natural rainfall over the seven-year period. Wheat grain yield was not improved or damaged due to subsoiling steep slopes. Over-winter water storage was improved by rotary subsoiling in two of the six-years of the experiment. In 2003, we simulated rainfall using a machine specifically developed for this purpose. Rotary subsoiling significantly reduced runoff during the final 50 min of rainfall simulation. Erosion was significantly reduced only during the 20 to 45 min period after runoff had begun. Based on the results of rainfall simulation, rotary subsoiling offers valuable soil and water saving benefits during intense, short duration rainstorms to farmers of newly fall planted wheat fields, fallowing a year of fallow, on steep slopes.
Technical Abstract: Subsoiling is the practice of ripping continuous open channels or creating pits using a rotary subsoiler to penetrate plow-pans for the purpose of improving root penetration of, and water infiltration into the soil profile. In the Pacific Northwest, precipitation ranges from 150 - 350 mm, and falls predominately from November to March when runoff and erosion can be severe on frozen or partially frozen soils. Experiments were conducted in six of seven years from 1996 through 2003 at six on-farm sites in eastern Washington to determine if rotary subsoiling reduced runoff and erosion, improved soil water storage, or affected crop yields. There were two treatments, rotary subsoiling and control. The rotary subsoiler created 40 cm deep pit with a4-L capacity every 0.7 m2. Runoff and erosion did not occur in either treatment at any location because of natural rainfall over the 7-year period. No differences in wheat grain yield were found between subsoiled and control plots when averaged over six years. Rotary subsoiling increased water stored over winter (P<0.05) in 2 of 6 years In 2003, rainfall was simulated for approximately three hours at a rate of 18 mm/hr on both subsoiled and control plots to determine runoff and erosion responses. Rotary subsoiling significantly reduced runoff during the final 50 min of rainfall simulation. Erosion was significantly reduced only during the 20 to 45 min period after runoff had begun. Rotary subsoiling can reduce runoff and increase water stored in the soil profile, and, during short duration, intense rainstorms, it provides valuable soil-saving benefits, in fall planted wheat fields on steep slopes, following summer fallow.