Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/2/2006
Publication Date: 7/1/2006
Citation: Wuest, S.B., Williams, J.D., Gollany, H.T. 2006. Tillage and perennial grass effects on ponded infiltration for seven semi-loess soils. Journal of Soil and Water Conservation, Vol. 61(4)218-223. Interpretive Summary: No-till and other conservation tillage methods, as well as perennial grass plantings, are promoted because they reduce soil erosion and improve water infiltration. We tested the effectiveness of no-till, in comparison to conventional tillage and perennial grass plantings at seven locations which represent the variation in climate and soil types in Umatilla County, Oregon. The sites were examples of soil management under normal commercial production by farmers. Averaged over all sites, water infiltration was significantly better under no-till or perennial grass compared to conventional tillage. At any particular site, or between the two years of measurements, however, there were large variations in infiltration. For example, a six-year-old stand of perennial grass may not always have greater infiltration than conventional tillage on a particular soil. It was also clear that soil type and climate can have a controlling effect on the effectiveness of soil management practices.
Technical Abstract: To test the benefits of no-till, we measured steady-state ponded water infiltration on a geo-climo sequence of seven soils where no-till, conventional till, and perennial grass fields were in close proximity. Average infiltration was 62% higher under no-till and grass compared to conventional tillage, although variability among sites and years was high. Infiltration correlated positively with sand content (r = 0.75), negatively with silt (r = -0.78), and negatively with water stable aggregates (WSA, r = -0.53). The number of years since tillage was positively correlated with infiltration, particulate organic matter (POM), permanganate oxidizable C (active C) and organic C (r = 0.40, 0.70, 0.48, 0.54 respectively). Among soil properties, organic C was positively correlated with active C, POM, WSA, and silt (r = 0.92, 0.58, 0.43, and 0.44, respectively). Despite the high variability, measurement of infiltration was the most effective test for documenting benefits of no-till, however, additional research with other indicators appears warranted.