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Summary of test site and agronomic practices.

 
Location Coalhurst, AB, Canada
Latitude and longitude 49°44′N, 112°57′W
Water management Rainfed
Crop year 2003–2004 2004–2005 2005–2006
Variable
Dates
 Residue management 27 Sept. 10 Sept. 7 Oct.
 Winter wheat seeding 27 Sept. 10 Sept. 7 Oct.
 Spring wheat seeding 24 Apr. 13 Apr. 12 May
 Winter wheat harvest date 3 Sept. 8 Sept. 28 Aug.
 Spring wheat harvest date 3 Sept. 8 Sept. 28 Aug.
Precipitation, mm
 1 Sept. to 30 Mar. (LT average = 145) 113.4 144.4 247.5
 1 Apr. to 31 May (LT average = 83) 126.2 38.6 71.0
 1 June to 31 July (LT average = 107) 120.1 281.8 97.9
 Total (long-term average = 335) 359.7 464.8 416.4



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Effect of residue management and direct seeding of winter and spring wheat planted into infested spring wheat stubble on adult wheat stem sawfly (WSS) emergence near Coalhurst, AB, Canada 2004–2006.

 
Winter wheat
Spring wheat
No. adults m−2
No. adults m−2
Factor Treatment Males Females Total WSS Males Females Total WSS
Harrow (main plot) Control-no harrow 14a† (1.2) 38a (3.2) 52a (4.1) 7 (1.0) 27a (3.1) 34a (3.9)
Heavy tine 20° 13ab (1.5) 31ab (2.5) 44ab (3.7) 6 (1.1) 19b (3.3) 24b (4.3)
Heavy tine 5° 9b (1.1) 25b (2.5) 35b (3.4) 6 (0.8) 17b (2.4) 23b (3.0)
Rotary harrow 25° 13a (1.4) 33a (3.0) 46a (3.9) 7 (1.0) 24a (2.6) 32a (3.4)
Rotary harrow 45° 14a (1.5) 36a (3.4) 51a (4.6) 5 (0.7) 19b (2.3) 25ab (2.9)
Seed drill (subplot) Chemical fallow-no seeding 17a (1.6) 48a (3.7) 65a (5.0) 11a (1.4) 32a (4.2) 45a (5.4)
Disc opener 14a (1.3) 33b (2.6) 48b (3.4) 6b (0.9) 18bc (2.1) 24bc (2.8)
Knife opener30 cm row spacing 10b (1.3) 30b (2.4) 42bc (3.3) 4bc (0.4) 18c (2.0) 22c (2.3)
Knife opener23 cm row spacing 11b (1.3) 26b (2.4) 38c (3.3) 5b (0.5) 20b (2.2) 25b (2.5)
Sweep opener23 cm row spacing 10b (1.0) 26b (2.6) 36c (3.4) 5c (0.7) 18bc (2.4) 23c (3.0)
Pr > F Harrow (H) 0.047 0.042 0.039 0.211 0.008 0.026
Drill (D) <0.0001 <0.0001 <0.0001 <0.0001 0.0004 <0.0001
H × D 0.714 0.697 0.321 0.036 0.294 0.049
Within main effect, means within columns sharing the same letter are not significantly different (P > 0.05; Fisher's Protected LSD). The numbers in parentheses are the standard error of the treatment. ANOVA and mean separation tests performed on transformed means [log10 (x+1)].



View Full Table | Close Full ViewTable 3.

Mean responses summarizing the pre-seed harrowing by seed drill interaction for adult wheat stem sawfly (WSS) emergence (adults m−2), collected in spring wheat planted into infested spring wheat stubble at Coalhurst, AB, Canada, 2004–2006.

 
Harrow (main plot)
Effect Treatments Control-no harrowing Heavy Tine20° Setting Heavy tine5° Setting Rotary harrow25° Setting Rotary harrow45° Setting Mean over all harrow treatments
Seed drill (Subplot) Chemical fallowNo recropping 54a† (13.8) 56a (18.3) 34a (9.3) 45a (9.2) 37a (8.5) 45a (5.4)
Disc opener18 cm row spacing 29b (5.8) 23b (5.0) 15b (4.5) 31ab (9.0) 25a (6.3) 25bc (2.8)
Knife opener30 cm row spacing 29b (6.3) 15 d (4.5) 20b (5.4) 23b (4.6) 22a (4.8) 22c (2.3)
Knife opener23 cm row spacing 35ab (7.0) 18bc (3.4) 27a (6.0) 25b (5.2) 22a (5.0) 25b (2.5)
Sweep opener23 cm row spacing 24b (6.0) 17cd (5.8) 18b (6.2) 34ab (7.7) 24a (7.9) 23c (3.0)
Mean over all seed drill treatments 34 a (3.9) 24 b (4.3) 22 b (3.0) 32 a (3.4) 25 ab (2.9)
Means within columns sharing the same letter are not significantly different (P > 0.05; Fisher's Protected LSD). The numbers in parentheses are the standard error of the treatment. ANOVA and mean separation tests performed on transformed means [log10(x+1)].



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Grain yield of winter wheat and spring wheat direct seeded into spring wheat stubble.

 
2004–2006
Factor Treatment Spring wheat Winter wheat
kg ha −1
Harrow (main plot) Control-no harrow 2438 (122) 2568 (100)
Heavy tine 20° 2482 (123) 2344 (110)
Heavy tine 5° 2573 (115) 2342 (109)
Rotary harrow 25° 2530 (129) 2366 (118)
Rotary harrow 45° 2620 (123) 2468 (121)
Seed drill (subplot) Disc opener 2483b† (117) 2706a (112)
Knife opener30 cm row spacing 2605ab (99) 2411b (87)
Knife opener23 cm row spacing 2715a (124) 2342bc (94)
Sweep opener23 cm row spacing 2294c (87) 2206c (94)
Pr > F Harrow (H) 0.487 0.804
Drill (D) <0.0001 <0.0001
H × D 0.041 0.677
In main effect, means within columns sharing the same letter are not significantly different (P > 0.05; Fisher's Protected LSD). The numbers in parentheses are the standard error of the treatment.



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Mean responses summarizing the spring pre-seed harrowing by seed drill interaction for grain yield of spring wheat direct seeded into spring wheat stubble at Coalhurst, Alberta, Canada, 2004–2006.

 
Harrow (main plot)
Effect Treatments Control-No harrowing Heavy tine20° Setting Heavy tine5° Setting Rotary harrow25° Setting Rotary harrow45° Setting Mean over all harrow treatments
Seed drill (subplot) Chemical FallowNo recropping
Disc Opener18 cm row spacing 2532a† (332) 2334bc (247) 2330b (98) 2778a (334) 2412b (205) 2483b (117)
Knife Opener30 cm row spacing 2471ab (232) 2758a (225) 2656ab (227) 2471bc (186) 2678ab (279) 2605ab (99)
Knife Opener23 cm row spacing 2553a (286) 2611ab (284) 2915a (252) 2673ab (299) 2849a (306) 2715a (124)
Sweep Opener23 cm row spacing 2207b (127) 2223c (230) 2318b (256) 2187c (189) 2527b (195) 2294c (87)
Mean over all seed drill treatments 2438a (122) 2482a (123) 2573a (115) 2530a (130) 2620a (123)
Means within columns sharing the same letter are not significantly different (P > 0.05; Fisher's Protected LSD). The numbers in parentheses are the standard error of the treatment.



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Pearson correlation coefficients relating wheat stem sawfly (WSS) emergence to grain yield in a spring or winter wheat system.

 
Pearson correlation coefficients
Wheat system Males Females WSS total
Winter wheat 0.15† 0.20* 0.23*
Spring wheat −0.05 ns‡ −0.16* −0.15†
*P ≤ 0.05.
P ≤ 0.10.
ns = P > 0.10.