GRAIN AND STRAW YIELDS OF BARLEY UNDER 4 TILLAGE SYSTEMS IN NORTHEASTERN ALBERTA

The agronomic feasibility of reduced tillage management for barley (Hordeum vulgare) production in northeastern Alberta was evaluated with respect to grain and straw yield. Five sites were established in 1988 and continued until 1992 within the Dark Brown, Black, and Gray soil zones. Four tillage management systems were studied including zero (ZT), minimum (MT), and two conventional systems (C1 and C2). Fungicide (propiconazole) was applied to one-half of the plots to evaluate the need for fungicide in a continuous barley rotation using reduced tillage systems. Fungicide had no effect on grain and straw yields and no interaction between fungicide and tillage system occurred thus indicating that fungal diseases controllable by propiconazole did not limit yields during this study. Tillage system significantly affected grain and straw yields in approximately one-third of the site-years studied. Grain yields averaged over 5 yr ranged from 2.55 to 4.27, 2.61 to 3.93, 2.51 to 4.08, and 2.63 to 3.99 Mg ha(-1) for ZT, MT, C2 and C1, respectively. Straw yields averaged over 5 yr ranged from 2.56 to 4.32, 2.61 to 3.90, 2.48 to 4.08, and 2.59 to 4.07 Mg ha(-1) for ZT, MT, C2 and C1, respectively. In general, grain and straw yields of barley under ZT were equal or superior to yields obtained under C1, C2 and MT systems. Straw yields followed closely the trends observed for grain yields. Zero tillage grain yields significantly exceeded those of C1, C2 and MT in 30-50% of the site-years when growing season precipitation was below normal. This is believed to be related to better soil water conservation and greater water use efficiency under ZT compared with other tillage systems in years with below normal precipitation and particularly when June and July precipitation was low.