| An integrated management system is vital for successful winter-wheat (Triticum aestivum L.) production in the semi-arid Canadian prairies. A 2-y study (1993/94-1994/95) was conducted at the Lethbridge Research Centre on a sandy clay loam Dark Brown Chernozem to evaluate the influence of crop rotation, tillage system, and row spacing on soil water and temperature. Winter-wheat performance was also evaluated. The study used plots established in 1984 following a split-split plot design. Treatments studied included combinations of three crop rotations (continuous winter wheat (WW), winter wheat-canola (WC), and winter wheat-fallow (WF)), two tillage systems (conventional (CT) and zero (ZT)), and two row configurations (uniform (UR) and paired (PR)).;Crop growth and yield correlated closely with fall soil water content to 1.5 m. In conclusion: (a) summer fallow is a viable option in winter-wheat rotations for increasing water reserves, (b) continuous winter wheat induced heavy infestations of downy brome and led, in turn, to reduced crop growth, (c) a 3-y rotation (fallow-winter wheat-canola) may be the best combination for winter wheat in semi-arid southern Alberta, (d) ZT succeeded when weeds could be controlled effectively and economically, (e) except under winter wheat after canola, paired-row seeding should not be used in combination with ZT.;Soil water conditions related largely to precipitation patterns and cropping sequence. During the over winter period beginning immediately after seeding, water content decreased on WF plots but partially increased on WC and WW plots. By spring, however, the WF rotation consistently had 40-70 mm more water to 1.5-m depth than the WW and WC rotations. In the WF rotation, ZT conserved more water than CT. The WF rotation generally had warmer soil temperatures during winter but cooler in early spring than those in continuously-cropped rotations. In all crop rotations, ZT soil temperatures were lower than those under CT but recovered later in the growing season. Soil temperature variations related more to crop-residue cover and soil-water content than to soil thermal properties. Row configuration had a minor influence on soil water and temperature. |
