Conservation Management Practices and Rotations for Irrigated Dry Bean Production in Southern Alberta.

The rotational benefits and greater economic returns of pulse crops, compared to cereals, have led to their increased production on the Canadian prairies. On irrigated land in southern Alberta, dry beans (Phaseolus vulgaris L.) are the pulse crop of choice. However, they are largely grown under conventional tillage systems at wide row spacings (60-75cm), which rely on inter-row cultivation for weed control and undercutting (soil disturbance leaving unanchored stubble) at maturity to facilitate harvest. Such practices may lead to declines in soil quality and increased risk of wind erosion risk. In contrast, solid-seeded dry beans in narrow rows (~20 cm row spacing) with no soil disturbance for weed control or harvest, offer a conservation management alternative. A 12-yr (2000-11) irrigated rotation study at Vauxhall, AB examined the impact of conventional (CONV) and conservation (CONS) management practices for dry beans, in rotations (3- to 6-yr in length) with potatoes (Solanum tuberosum L.), sugar beets (Beta vulgaris L.), soft wheat (Triticum aestivum L.) and timothy (Phleum pratense L.). As well as narrow rows, CONS management included direct seeding, a fall rye (Secale cereale L.) cover crop, and feedlot manure compost additions. Averaged over 12 yr, there was no significant yield difference between CONV (2170 kg ha^-1) and CONS (2215 kg ha^-1) rotations. However, average maturity was significantly earlier (by 4 d) on CONS beans. Even though white mold [Sclerotinia sclerotiorum (Lib.) de Bary] infection rate (averaged over 12 yr) was significantly higher (22%) on CONS rotations compared with CONV rotations (6%), this did not affect average yields. Incidence of common bacterial blight [Xanthomonas axonopodis pv. phaseoli (Smith)] was unaffected by management system or rotation. The study demonstrated that narrow-row production of dry beans (CONS) resulted in equivalent yields to wide-row production (CONV) over a 12 yr study period which bodes well for increased adoption of this system in the future.