Soil macroporosity,hydraulic conductivity and air permeability of silty soils under long-term conservation tillage in Indiana |
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| Institution: | 1. Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA 50011, USA;2. National Laboratory for Agriculture and the Environment, USDA Agriculture Research Service, Ames, IA 50011, USA;3. Northern Research Station, USDA Forest Service, Grand Rapids, MN 55744, USA;1. College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China,;2. College of Urban and Environmental Sciences, Northwest University, Xi''an, Shaanxi 710127, China;3. College of Natural Resources and Environment, Northwest A&F University, Yangling, Shannxi 712100, China;4. School of Environment and Natural Resources, The Ohio State University/The Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA |
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| Abstract: | With the increasing use of conservation tillage, many questions about the long-term effects of tillage system on soil physical properties have been raised. Studies were conducted to evaluate saturated hydraulic conductivity (KSAT), macropore characteristics and air permeability of two silty soils as affected by long-term conservation tillage systems in the state of Indiana. Measurements were taken during the tenth year of a tillage study on a Chalmers silty clay loam (Typic Haplaquoll) and the fifth year of a study on a Clermont silt loam (Typic Ochraqualf). Tillage systems were moldboard plow, chisel, ridge till-plant, and no-till in a rotation of corn (Zea mays L.) and soya beans (Glycine max L.). Saturated hydraulic conductivity was measured on large soil columns (25 × 25 × 40 cm) before spring tillage, and macropore size and continuity were assessed with staining techniques. Intact soil cores (8 cm diam × 10 cm) were collected in early July in the row and non-trafficked interrow at three depths (10–20, 20–30, and 30–40 cm) and were analyzed for air permeability (Kair), air-filled porosity and bulk density. Saturated hydraulic conductivity values were in the order plow > chisel > ridge till > no-till for the Chalmers soil and were significantly greater in the plow treatment than in the other 3 tillage systems on the Clermont soil. Differences in KSAT between the 2 soils were generally greater than differences among tillage systems, and coefficients of variation were lower for treatments that did not include may fall tillage operations. At the 10-cm depth on the Chalmers soil, the chisel treatment had the greatest number of stained cylindrical channels, whereas for the Clermont soil the ridge till had the greatest number at this depth. Although the no-till treatment had similar or fewer total channels, it had the most continuous channels from the 10-cm depth to the 20- and 30-cm depths on both soils. Tillage system, row position and depth all affected Kair. On the Chalmers soil, plow, chisel and ridge systems had lower Kair between rows than in the row at the 10–20-cm depth, whereas no-till had constant Kair in the row and between the row. On the Clermont soil, ridge till had the highest Kair of all treatments at the 10–20-cm depth, and no-till had the highest Kair of all treatments at the 20–30-cm depth. |
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