Managing an Annual Legume Green Manure Crop for Summerfallow Replacement in the Canadian Prairies.
(A08-zentner968220-poster)
Authors:
R.P. Zentner* - Agriculture & Agri-Food Canada C.A. Campbell - Agriculture & Agri-Food Canada V.O. Biederbeck - Agriculture & Agri-Food Canada F. Selles - Agriculture & Agri-Food Canada
R. Lemke - Agriculture & Agri-Food Canada P.J. Jefferson - Agriculure & Agri-Food Canada Y. Gan - Agriculture & Agri-Food Canada
Abstract:
It is suggested that in the semiarid Canadian Prairies an annual legume green manure crop (GM) could be used as a partial-summerfallow (F) replacement to protect the soil and increase its N fertility, particularly when combined with snow trapping to replenish water used by the legume. We assessed this possibility for hard red spring wheat (W) grown in rotation with Indianhead black lentil (i.e., GM-W-W) vs. a F-W-W system. Further, we assessed whether a change in management of the GM crop (i.e., moving to earlier seeding and earlier turn-down) improved its overall performance. The study was conducted for 12 years (1988-99) on a loam soil at Swift Current, SK. (Wheat stubble was left tall to trap snow, tillage was minimized, and wheat was fertilized based on soil tests). When examined after 6 years, we found that by waiting for full bloom of the legume to maximize N2 fixation, soil water was being depleted to the detriment of the following wheat crop. However, with the change in management of the GM crop in 1994, wheat yields following GM have equalled those after fallow. It also produced a significant increase in grain protein for GM-W-W compared to F-W-W, and lead to a gradual decrease in fertilizer N requirements of wheat in the GM system in the last 6 years. These savings, together with reduced costs for tillage and herbicides on partial-fallow vs conventional-fallow areas, and higher revenues from enhanced grain protein, more than offset the added costs for the GM crop.
Speaker Information: Robert Zentner, Agriculture & Agri-Food Canada, Semiarid Prairie Agricultural Research Centre Box, Swift Current, SK S9H 3X2; Phone: (306) 778-7265; E-mail: [email protected]
Session Information: Monday, November 3, 2003, 4:00 PM-6:00 PM Presentation Start: 4:00 PM (Poster Board Number: 331)
Keywords: legume green manure; summerfallow replacement; wheat-fallow; semiarid