Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 27, 2007
Publication Date: May 18, 2008
Citation: Jabro, J.D., Sainju, U.M., Stevens, W.B., Lenssen, A.W., Evans, R.G. 2008. Long-term tillage frequency effects on dryland soil physical and hydraulic properties. International Soil Conservation Organization Conference Proceedings. May 15-23, 2008. Budapest, Hungary. Technical Abstract: Long-term tillage influences physical, chemical, and biological properties of the soil environment and thereby crop production and quality. We evaluated the effect of long-term (> 22 years) tillage frequency [no-till (NT), spring till (ST), and fall and spring till (FST)] under continuous spring wheat (Triticum aestivum L.) on soil penetration resistance (PR), bulk density (BD), gravimetric water content (GWC) and saturated hydraulic conductivity (Ks) under dryland cropping systems in northeastern Montana, USA. Tillage frequency influences on these physical properties were tested on a Dooley sandy loam soil (fine-loamy, mixed Typic Argiborolls) in a randomized complete block design with four replications. Soil PR was measured by a digital penetrometer in 2.5-cm increments to a depth of 25 cm at three locations across each plot. Undisturbed soil cores were sampled at 0 to 5, 5 to 10, and 10 to 15 cm depths and were used to measure BD, GWC, and particle size distribution. Soil PR was significantly greater in the NT than in ST and FST treatments at 0 to 10 cm depth, but was greater in FST than in NT and ST at a depth deeper than 10 cm. In all three treatments, soil PR generally increased to a depth of 10 to15 cm and then decreased beyond this depth. Long-term tillage reduced soil compaction in the surface (0 to 10 cm), but increased in the subsurface at a depth > 10 cm due to the traffic intensity induced by tillage mechanism. Soil BD was not affected by tillage and averaged 1.59, 1.58, and 1.61 Mg m-3 for NT, ST, and FST, respectively. Similarly soil GWC was not influenced by tillage and generally decreased with increased intensity of soil manipulation and tillage frequency. Soil Ks at 15 to 20 cm depth generally decreased with increased tillage frequency. The results showed that soil BD, GWC and Ks were minimally influenced by tillage intensity after 22 year of treatment imposition.