Monday, November 13, 2006
105-12

Impact of Winter Wheat Management on Underseeded Red Clover.

Bill Deen and Hugh Earl. Univ of Guelph, Dept Plant Agriculture, Guelph, ON N1G 2W1, Canada

Dramatic increases in nitrogen fertilizer costs have renewed interest in red clover as a nitrogen source in corn/soybean/winter wheat rotations in Southwestern Ontario. Red clover, under-seeded to winter wheat in Ontario, provides an 82 kg ha- 1 nitrogen credit to a subsequent corn crop.  Under-seeding red clover to winter wheat, however, often results in non-uniform stands and corn growers typically respond by applying a uniform nitrogen rate across the field ignoring the presence of the non-uniform red clover.  This practice results in significant over application of nitrogen in areas of the field where red clover did establish, thereby creating nitrogen rich zones that have increased potential for nitrogen loss to the environment.  Field trials were conducted to assess winter wheat nitrogen and tillage system effects on red clover stand.   Four nitrogen rates (O, 40, 80 and 120 kg ha-1) were applied to winter wheat in replicated plots at twelve locations.  Winter wheat yield, red clover stand and biomass were measured.   Using long-term rotation plots located at Elora, Ontario, the effect of two tillage systems (conventional and no-till) on winter wheat yield and red clover stand establishment when under-seeded to winter wheat were evaluated. Both nitrogen rate and tillage system significantly influenced red clover biomass following wheat harvest.  Conventional tillage resulted in a 48% increase in red clover dry weight, and a 6.7% increase in wheat yield compared to no-till.

Handout (.pdf format, 107.0 kb)

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