Duration of Tartary Buckwheat (Fagopyrum tataricum) Interference in Several Crops

Field studies were conducted over a 7-yr period at Lacombe, Alberta, to study the relationship between the duration of Tartary buckwheat interference [Fagopyrum tatarium(L.) Gaertn. # FAGTA] and yield of barley (Hordeum vulgareL.), oats (Avena sativaL.), wheat (Triticum aestivumL.), flax (Linum usitatissimumL.), and rapeseed (Brassica campestrisL.). The data were pooled over years and analyzed by multiple regression. The equations were as follows: ŷ = 15.46 + 0.39X1+ 0.00x2−0.11x3(barley), ŷ = −15.44 + 0.49x1+ 0.02x2+ 0.08x3(oats), ŷ = −2.04 + 0.39X1+ 0.05x2-0.03x3(wheat), ŷ = −4.38 + 1.14x1−0.04x2+ 0.01x3(flax), and ŷ = −13.85 + 0.40x1– 0.01x2+ 0.04x3(rapeseed); where ŷ was the estimated percent yield loss of the crop, x1was the duration (days) of the Tartary buckwheat in the crop, x2was the number of Tartary buckwheat plants/m2, and x3was the number of crop plants/m2. The time that Tartary buckwheat remains in the crop contributed most to the yield loss observed in all crops. Yield loss between 0.4 and 1.1% per day was attributed to this variable alone. For a given x1, x2, and x3value the order of percent yield loss was flax>oats>wheat> barley>rapeseed.