Effect of tillage system and crop sequence on irrigated sugarbeet production

Abstract

Sugarbeets (Beta vulgaris L.) are grown on intensively tilled-irrigated land in southern Alberta, which is subject to soil erosion by wind. Experiments were conducted on commercial fields near Burdett, AB, to determine the effect of the tillage system and previous crops on sugarbeet production. The previous crops were dry bean (Phaseolus vulgaris L.) or wheat (Triticum aestivium L.) and the tillage systems were conventional (moldboard plow, vibrashank cultivator, harrow, packer), minimum (double disc, self-cleaning harrow, glyphosate) or no tillage (glyphosate). After dry beans, sugarbeet fresh weight and extractable sugar yields were similar with all tillage systems. All of the tillage systems left less than 100 g m-2 of plant residue on the soil surface in the spring following dry beans, which is insufficient to protect the soil from wind erosion. After wheat, sugarbeet yields were similar with minimum and conventional tillage but lower with no tillage. Both minimum and no-tillage systems left sufficient plant residue on the soil surface to protect the soil from erosion (> 200 g m-2). Sugarbeet stand density following wheat was lower with no tillage than conventional or minimum tillage, reflecting poor seed placement and daily maximum soil temperature (5 cm depth) of up to 10°C lower under no tillage than conventional tillage. After wheat, there was a trend toward lower densities of hard-seeded annuals, such as redroot pigweed (Amaranthus retroflexus L.), after no tillage than conventional tillage. Of the cropping systems tested in this study, only the minimum tillage system after wheat provided optimum sugarbeet yield and left enough plant residue to protect the soil from wind erosion. Key words: Crop rotation, bean, wheat, sugarbeet, no-tillage