Fertilizer responses of dry bean in southern Alberta

Previous reports suggest that the response of dry bean to N fertilizer is often dependent on bean cultivar. In addition to N, commercial producers of dry bean in southern Alberta frequently apply P, K and Zn, even though soil test levels of these nutrients are often high. To evaluate the fertilizer responses of commercial dry bean cultivars in southern Alberta, three experiments were conducted. In the first experiment, the response of GN 1140 great northern bean, NW-63 small red bean, Othello pinto bean, and Viva pink bean to N fertilizer rates and rhizobia inoculation was determined at three sites each year from 1994 through 1996. The second experiment was conducted at the same sites to determine the response of these cultivars to P and K fertilizer. The third experiment was conducted at the same sites in 1995 and 1996 to determine the response of the same four cultivars and OAC Seaforth navy bean to soil-applied and foliar Zn application. The four cultivars responded similarly to N in the first experiment. Seed yields ranged from 81 to 100% of maximum yields when available N levels (fertilizer-N plus nitrate-N to 30 cm just prior to seeding) were less than 80 kg N ha(-1), but were always greater than 90% of maximum yields when available N levels were greater than 80 kg N ha(-1). Rhizobia inoculation did not significantly increase seed yields or reduce the response to N fertilizer, although early-season plant growth was frequently improved by inoculation. Seed yield was only increased by application of P fertilizer at one site and by application of K fertilizer at one site, while application of Zn did not increase seed yield at any of the sites. The critical soil test levels for responses to P, K or Zn were consistent with levels reported for other crops or regions, but further validation of these levels is required due to the lack of sites with low nutrient availability.