Submitted to: World Congress of Soil Science
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2006
Publication Date: 7/9/2006
Citation: Jiang, P., Anderson, S.H., Kitchen, N.R., Sadler, E.J., Sudduth, K.A. 2006. Landscape and conservation management effects on soil hydraulic properties for an epiaqualf. World Congress of Soil Science.
Technical Abstract: Tillage and conservation management systems have been developed to reduce the environmental impacts of crop production systems, and have been reported to influence soil hydraulic properties. However, the effects of landscape positions and their interaction with management systems have received less attention. The objective of this study was to investigate the effects and possible interactions of landscape position and selected tillage and conservation management systems on saturated hydraulic conductivity (Ksat), soil water retention, pore size distributions, and bulk density for a Mexico silt loam (fine, smectitic, mesic Aeric Vertic Epiaqualf), a claypan soil. Landscape positions included summit, backslope and footslope positions. Management treatments included mulch tillage with a corn (Zea mays)-soybean (Glycine max) rotation (MTCS); no-till with a corn-soybean-wheat (Triticum aestivum) rotation (NTCSW) with a red clover (Trifolium pretense) cover crop following wheat; conservation reserve program system with primarily tall fescue (Festuca arundinacea) intermixed with legumes (CRP); and a hay crop system (Hay) consisting of legumes and cool season and warm season grasses. The study site was a 12-ha area in central Missouri. Treatment plots were in a randomized block design with three replications. Soil properties were determined on intact soil cores (76 mm long x 76 mm diam) collected from the 0 to 10, 10 to 20, and 20 to 30 cm soil depths at each landscape position and management treatment. Soil water retention was measured at 0, -0.4, -1, -2.5, -5, -10, and -20 kPa soil water pressure. The water retention data were analyzed using multivariate profile analysis, while all other parameters were analyzed using the ANOVA procedure in SAS. Soil bulk density was different among landscape positions, management treatments, and soil depths. For the management treatments, bulk density was lowest for the CRP (1.25 g/cm), intermediate for the MTCS treatment (1.28 g/cm) and highest for the Hay (1.32 g/cm) and NTCSW (1.34 g/cm) treatments. By landscape position, bulk density was higher for the footslope position (1.36 g/cm) than for the backslope (1.28 g/cm) and summit (1.26 g/cm) positions. Management effects were strongest at the footslope (p = 0.0007) and moderate at the backslope (p = 0.0204), while there were no effects at the summit (p = 0.43). Ksat was also affected by management. The descending order of Ksat for the 0-10 cm depth was CRP (165 mm/hr) > Hay (42 mm/hr) = NTCSW (36 mm/hr) > MTCS (30 mm/hr). Interactions between landscape position and tillage treatments occurred for the MTCS and NTCSW treatments. The MTCS treatment had the lowest Ksat at both the backslope and summit positions, while this treatment had a higher value (81 mm/hr)at the footslope position compared to the NTCSW treatment (18 mm/hr). Management effects on Ksat appeared to be limited to the surface soil depth. Water retention data showed that for the 0-10 cm depth, water contents for the CRP treatment were the highest, while those for the MTCS treatment were the lowest for all soil water pressures. Saturated water content for CRP (0.42 m**3/m**3) was 27, 24, and 14% higher than MTCS (0.33 m**3/m**3), NTCSW (0.34 m**3/m**3), and Hay (0.37 m**3/m**3), respectively. Water contents for CRP and Hay were comparable at all non-zero soil water pressures. Further, NTCSW tended to retain more water than MTCS at all pressures, but the difference was only significant at -20 kPa. In summary, both landscape position and management affected soil hydraulic properties on these claypan soils. Based on the soil properties considered, CRP was superior in soil water conservation than other management treatments. Most importantly, the results of this study indicated management effects differed significantly with landscape position. These interactions were likely due to varying t