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United States Department of Agriculture

Agricultural Research Service

Title: Tillage effects on physical properties in two soils of the Northern Great Plains

Authors
item Jabro, Jalal "jay"
item Stevens, William
item Evans, Robert
item Iversen, William

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 24, 2009
Publication Date: July 1, 2009
Repository URL: http://hdl.handle.net/10113/35057
Citation: Jabro, J.D., Stevens, W.B., Evans, R.G., Iversen, W.M. 2009. Tillage effects on physical properties in two soils of the Northern Great Plains. Applied Engineering in Agriculture. 24(3): 377-382.

Interpretive Summary: We evaluated the effects of conventional (CT) and strip (ST) tillage practices on bulk density ('b), gravimetric water content ('w), and saturated hydraulic conductivity (Ks) at the soil surface and at 10 - 15 cm depth in two soils of the Northern Great Plains (NGP). Tillage treatments significantly affected soil 'b and 'w in clay loam soil at the EARC site, while 'b and 'w did not differ significantly between CT and ST in sandy loam at the Nesson site. Soil 'b was generally lower in ST plots than in CT plots while 'w was greater for ST than for CT regardless of soil type. The log transformed Ks at the soil surface did not differ significantly between CT and ST practices at either site. The effect of tillage on log-transformed Ks at the 10 - 15 cm depth was significant in both sandy loam and clay loam soils at P < 0.10 and 0.05 levels, respectively. The Ks values were always greater in ST plots than CT plots at both sites. The Ks values at the 10 - 15 cm depth were 23% and 138% greater for ST than for CT at Nesson and EARC sites, respectively. The variation in Ks values in soil at 10 - 15 cm depth was likely due to differences in soil compaction and vehicular traffic passes peculiar to the CT and ST systems. The ST plots likely had better volume of macropores than CT plots, producing greater water flow through the ST soil profile and consequently enhanced water storage capability as reflected by wetter soil conditions under ST system. The tillage practice selected--whether CT, ST or any alternative--impacts soil physical properties and may affect crop growth and yield by enhancing water movement and retentivity, increasing soil aeration, and minimizing physical limitations that restrict root growth and distribution. The conclusions drawn from this study can be generalized to soils similar to Lihen and Savage soil series as well as their soil associations.

Technical Abstract: Tillage practices profoundly affect soil physical and hydraulic properties. It is essential to select a tillage practice that sustains the soil physical properties required for successful growth of agricultural crops. We evaluated the effects of conventional (CT) and strip (ST) tillage practices on bulk density ('b), gravimetric water content ('w), and saturated hydraulic conductivity (Ks) at the soil surface and at 10 - 15 cm depth in two soils of the Northern Great Plains (NGP). Soil cores were collected from each plot at 0 - 10 and 10 - 20 cm depths under each tillage practice at both sites to measure 'b and 'w. In-situ Ks measurements at the soil surface and at 10 - 15 cm depth were determined using a pressure head infiltrometer (PHI) and a constant head well permeameter (CHWP), respectively, at two sites, one in North Dakota (Nesson, mapped as Lihen sandy loam) and one in Montana (EARC, mapped as Savage clay loam). The Ks measurements were made approximately 1 m apart in the center of crop rows within CT and ST plots of irrigated sugarbeet (Beta vulgaris L.). Tillage treatments significantly affected soil 'b and 'w in clay loam soil at the EARC site, while 'b and 'w did not differ between CT and ST in sandy loam at the Nesson site. The log-transformed Ks at the soil surface did not differ significantly between CT and ST practices at either site. The effect of tillage on log-transformed Ks at the 10 - 15 cm depth was significant in both sandy loam and clay loam soils at P < 0.10 and 0.05 levels, respectively. The Ks values at 10 - 15 cm depth were 23% and 138% greater for ST than for CT at Nesson and EARC sites, respectively. Differences in soil compaction as evaluated through 'b data at 10 - 20 cm depth explain Ks variations between the CT and ST systems at both sites. It was concluded that the CT operations increased soil compaction, which consequently altered 'b, thereby reducing Ks in the soil.

Last Modified: 9/20/2014
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