Long-Term Tillage Effects On Soil Physical Properties Under Dryland Conditions In Northeastern Montana.

Understanding the effect of long-term tillage and cropping sequence on soil physical properties is essential for cropping systems sustainability. We evaluated a 21-yr effect of  combination of tillage and cropping sequence on soil bulk density (Bd), gravimetric moisture content (GMC) and saturated hydraulic conductivity (K_s) of a Dooly sandy loam (fine-loamy, mixed, superactive, frigid Typic Argiustolls) at 0 to 10 and 10 to 20 cm depths in Northeastern Montana. Five tillage and cropping sequences were no-tilled continuous spring wheat (NTCW), spring-tilled continuous spring wheat (STCW), fall- and spring-tilled continuous spring wheat (FSTCW), fall-and spring-tilled spring wheat-barley followed by spring wheat-pea (FSTW-B/P) and spring-tilled spring wheat-fallow (STW-F). The statistical results showed that soil BD, GMC and K_s were significantly influenced by tillage and cropping system at 0 to 10 cm depth. Soil Bd was significantly greater in STW-F than in STCW at both depths. Soil GMC was greater in NTCW than in FSTW-B/P and STW-F, and K_s was greater in NTCW than in FSTW-B/P at 0 to 10 cm depth.  However, both soil GMC and K_s were not significantly affected by neither tillage nor cropping sequence at 10 to 20 cm depth.