Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/5/2007
Publication Date: 11/5/2007
Citation: Jabro, J.D., Stevens, W.B., Evans, R.G., Iversen, W.M. 2007. Effect of Tillage on Soil Hydraulic Conductivity in Two Contrasting Soil Textures. Agronomy Abstracts. In: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting, November 4-9, 2007, New Orleans, Louisianna. CD-ROM.
Technical Abstract: Tillage profoundly affects soil physical and hydraulic properties. It is essential to select a tillage system that sustains the soil hydraulic properties required for successful growth of agricultural crops. We compared effects of conventional tillage (CT) and strip tillage (ST) systems on field-saturated hydraulic conductivity (Kfs) in two different-textured soils. In-situ Kfs measurements were determined in each soil using a pressure ring infiltrometer (PI) and a constant head well permeameter (GP) at the soil surface and subsurface layers. Measurements were made at three soil depths (surface, 9 - 15 cm, 17 - 20 cm) at two sites–one in North Dakota (Nesson, mapped as Lihen sandy loam) and one in Montana (EARC, mapped as Savage clay loam). Kfs measurements were made approximately 1 m apart within the crop row of irrigated sugarbeet (Beta vulgaris L.). Statistical analysis showed that soil surface Kfs values were significantly higher than those at 9 - 15 and 17 - 20 cm depths regardless of soil texture and tillage system. Kfs values differed significantly between the two locations due to variations in soil texture at tested soil depths in both CT and ST systems. Kfs values at Nesson were 1.4 - 4 times higher than Kfs values at EARC location. In both tillage systems, Kfs decreased with depth. The effect of tillage system on Kfs was significant only at the 9 – 15 cm depth, regardless of soil texture, with Kfs values in ST plots an average of 1.8 times higher than those in CT plots. Differences in soil structure, macroporosity and soil compaction at 9 - 15 cm depth explain Kfs variations between the CT and ST systems at both locations. It is clear that macropore size distribution, continuity, and soil compaction induced by tillage system critically affect water flow into and through the soil. It was concluded that tillage system significantly impacts soil hydraulic properties and may affect both crop growth and yield. Keyword: Hydraulic conductivity; tillage; macroporosity; compaction