|Schillinger, William - WASH STATE UNIVERSITY|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 28, 2004
Publication Date: April 19, 2006
Citation: Kennedy, A.C.W.F. Schillinger. 2006. Soil quality and water intake in conventional-till vs. no-till paired farms in Washington's Palouse Region. Soil Sci. Soc. Amer.J. 70:940-949 Interpretive Summary: Background description impact Growers in the United States and worldwide are adopting conservation cropping practices to reduce soil erosion, improve soil quality, increase water infiltration, and reduce the number of tillage passes. Changes in the soil ecology that occur with no-till (NT) are dependent on many factors, such as soil type and depth, precipitation, temperature, and residue management. Soil quality characteristics varied with tillage and landscape position. We found that soil organic carbon in NT was greater than in conventional tillage (CT). Soil microbial activity (MA) and pH were higher in CT compared to NT due to a natural calcium carbonate layer. Microbial communities in CT at back-slope and toe-slope positions were different from those in NT, while summit communities were not different. Over-winter soil water storage and ponded water infiltration rates were similar regardless of tillage history. Over-winter soil water storage differed with landscape position. Several soil quality measurements are needed to adequately evaluate soils. These data quantify soil quality and soil water dynamics as affected by long-term tillage on the Palouse. This research illustrates to growers, scientists and field people soil quality characteristics that change with management options in the dryland cropping region of the Inland Pacific Northwest. This information will help growers in developing management systems that reduce erosion, improve soil quality, and maintain productivity.
Technical Abstract: Many farmers in the steeply-sloped Palouse region of eastern Washington and northern Idaho practice no-till (NT) farming because water erosion is often severe. Soil quality and water intake parameters were assessed in wheat (Triticum aestivum L.) stubble along summit, back, and toe slope positions in a 2-yr study at three paired-farm sites under conventional-till (CT) vs. NT management. Paired sites had similar south-facing slope and aspect. NT fields had not been tilled from 2- to 20 yr. Soil organic carbon (OC) in NT was greater than in CT. Sites had calcium carbonate (caliche) at the back-slope position and pH was higher in CT compared to NT. Soil microbial activity (MA) was stimulated with CT, mainly due to the exposed caliche layer and higher pH; not due to higher OC, indicating the need to use several quality parameters to evaluate soils. Microbial communities in CT at back-slope and toe-slope positions were different from those in NT, while summit communities were not different. There were no differences in over-winter soil water storage (OWS) or ponded water infiltration rate (PWI) in undisturbed standing wheat stubble between CT and NT, indicating that soils with equivalent quantity of standing stubble have similar OWS and PWI regardless of tillage history. However, OWS differences were measured among landscape positions with toe > back > summit. These data further quantify soil quality and soil water dynamics as affected by long-term tillage management on cropland in the Palouse.