Update on winter wheat projects from the agronomy project Enhanced Economic Returns and Ecosystem Services with the Expansion of Winter Wheat May 14, 2013 Beres, B. L.1, Irvine, R. B.2, Turkington, T. K.3, Johnson, E. N.4, O’Donovan, J. T.3, Harker, K. N.3, Stevenson, F.C.5, Peng, G.6, Lafond, G. P.7, Holzapfel, C.7, Mohr, R.M.2, Spaner, D.M.8, Kutcher, H.R.9, H.A. Cárcamo1. 1Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403 1st Avenue South Lethbridge AB T1J 4B1 (e-mail: [email protected]); 2Agriculture and AgriFood Canada, Brandon Research Centre, Box 1000A, RR#3, Brandon, MB R7A 5Y3; 3Agriculture and Agri-Food Canada, Lacombe Research Centre, Lacombe, AB T4L 1W1; 4Agriculture and AgriFood Canada, Scott Research Farm, PO Box 10, Scott, SK S0K 4A0; 5142 Rogers Rd., Saskatoon, SK S7N 3T6; 6Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, SK S7N 0X2; 7Agriculture and AgriFood Canada, Indian Head Research Farm, PO Box 760, Indian Head, SK S0G 2K0; 8Dept. of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5; 9Crop Development Centre, University of Saskatchewan, Saskatoon, SK S7N 5A8. Executive Summary The overall objective of this DIAP project was to overcome obstacles in the adoption of winter wheat in western Canada. A two-fold approach was undertaken towards this objective. Firstly, studies were established to broaden the stubble acreage available late summer for seeding winter wheat. This included using alternate stubble types, managing alternate stubble types, and through the use of seed treatments to expand the amount of stubble available to seed winter wheat into in late summer. Secondly, studies were established to evaluate a number of pest and nutrient management strategies to promote winter wheat plant health, growth and yield stability. Improving these components of winter wheat allow producers to widen the length of the seeding window or seed into less optimum conditions and still realize reasonable success. The overarching theme of the research was the development of improved management practices. The results of a number of the studies have provided some invaluable information for the industry. Furthermore, since this study was largely a collaboration of AAFC investigators, Ducks Unlimited Canada, and the producer-directed winter cereal commissions of the three Prairie Provinces, there has been several opportunities and venues to conduct extension events to transfer the information learned directly to the farm gate. For example, we have already observed a significant increase in the adoption of seed treatments, stubble alternative to canola such as pea stubble were proven to provide similar results, a better understanding of controlled-release N products has been derived from this project, and new chemistries have been identified to improve weed management systems for winter wheat. Additional research is still required to reap all of the benefits of these studies and a number of these studies require more data collection but the activities conducted in this DIAP initiative have certainly provided an excellent starting point to supporting increased successful winter wheat production. The first field season (2011) of the winter wheat project was challenging, but it was interesting to see that the winter wheat plots generally looked best on field day tours comnpared to the spring annual plots. In many cases, there were no spring annual plots due to flooding. In 2012, most experiments were conducted and executed without incident. In some experiments, we now have up to 19 site-years collected and will be continuing with other experiments to generate the necessary data required to adequately test to address the experimental objectives. Human Resources We have a few notable changes to our science team over the course of the study. Dr. Gary Peng assumed Dr. Randy Kutcher s role on the team. Dr. Ramona Mohr agreed to assume Dr. Byron Irvine’s science duties related to these winter wheat studies. We used this project as an opportunity to recruit and train Graham Collier, a graduate student under the supervision of Dr. Dean Spaner at the University of Alberta and Dr. Shuhao Qin, a visiting scientist from Gansu Agricultural University in the Gansu province of China working with Dr. Brian Beres. On a much sadder note, we have lost Dr. Guy Lafond to cancer. The impact of Guy’s passing will extend across the various projects that he lead or co-investigated. We are currently assessing how to deal with the optical sensor activities and data that Guy was leading. Sub-Activity Updates Sub-activity 1.1 (Test 211) Determine the influence of seed-applied fungicides and insecticides on fall stand establishment and overwinter survival of winter wheat. Seed Treatment Results A total of 20 sites were established over the course of two growing seasons (2010-2011 and 2011-2012). Plant stand was not affected by the treatments, despite the fact the treatment visibly seemed to have affected winter wheat stand and growth early in the growing season (Fig. 1 and Table 1). Grain yield was improved relative to the untreated check when seed was treated with Imidacloprid insecticide or with Tebuconazole + Metalxyl fungicides + Imidacloprid insecticide (Raxil WW). The application of foliar fungicide (Prothioconazole – ‘Proline’) increased yield slightly to 4.56 Mg ha-1 from 4.50 Mg ha-1 (check). These results are intriguing as it would appear that the fungicide application elicited a favorable plant physiological response even in the absence of symptoms from foliar pathogens (e.g., strip rust at 200-11 sites). Furthermore, contrasts indicated that foliar fungicide positively affected stand survival and kernel wt., and nearly yield only with metalaxyl seed treatment. For test wt., the effect of foliar fungicide was significant only with Imidacloprid. Fig. 1. Photo on left shows control treatment (no seed treatments applied) of CDC Buteo planted south of Lethbridge. Photo of right shows Raxil WW treatment of CDC Buteo planted south of Lethbridge. Table 1. Winter wheat responses to seed treatment and fall applied foliar fungicide Prothioconazole. Survival Yield Kernel wt. Test wt. Check Fung Check Fung Check Fung Check Fung (%) (Mg ha-1) (mg) (kg hL-1) Check 109 113 4.42 4.52 34.1 34.0 80.0 79.9 Tebuconazole 113 112 4.52 4.56 34.1 34.1 79.9 79.9 Metalxyl 106 116 4.41 4.53 33.8 34.3 79.8 79.9 Imidacloprid 110 112 4.51 4.60 34.0 33.8 80.1 79.9 Combination 114 112 4.62 4.61 34.0 34.2 79.9 79.9 LSD0.05 6 0.12 0.5 0.2 Abbreviations: Fung = fall foliar applied fungicides (Prothioconazole) and Combination = seed treatment combination of Tebuconazole + Metalxyl + Imidacloprid. A plot of mean grain yield and the coefficient of variation for all treatment combinations showed that the check and metalaxyl seed treatment combinations were in the lesser yielding quadrats than other seed treatment combinations including Tebuconazole and Imidacloprid (Fig. 2). Also, treatments including foliar fungicide, Prothioconazole resulted in more stable (lesser CV) yields. The treatment providing the most stable, greater yields was the ‘combination’ seed treatment with fall-applied foliar fungicide, thus representing one way to stabilize winter wheat production on the Canadian Prairies. 4.8 Group I Group II ) Comb-Chk 1 ‐ a 4.6 Teb-Pro h Imi-Pro   Comb-Pro Imi-Chk g M Met-Pro Teb-Chk Chk-Pro (   d Met-Chk Chk-Chk l 4.4 e i Y Group IV Group III 4.2 25 30 35 40 Coefficient of Variation (%) Group I: High mean, low variability (optimal) Group II: High mean, high variability Group III: Low mean, high variability (poor) Group IV: Low mean, low variability Fig. 2. Biplot of grain yield vs. coefficient of variation for each treatment combination. Abbreviations: Chk = Check, Teb = Tebuconazole, Met = Metalxyl, Imi = Imidacloprid, Tebuconazole + Metalxyl + Imidacloprid, and Pro = fall foliar applied fungicides (Prothioconazole). Sub-activity 1.2 (Test 212) Improving the success of planting winter wheat into barley grain stubble. One of the goals of this project is to successfully grow winter wheat in stubble other than canola. Barley would be a reasonable alternative, particularly in shorter season areas. We were interested to see what management strategies would be needed to control volunteer barley. Volunteer barley was suppressed by the winter wheat (cv. CDC Buteo) at all locations in 2010. Therefore, we concluded that we should instead change the objective to the following: Determine the efficacy of novel herbicides in controlling weeds in sub-optimal and optimal stands of winter wheat. If a producer does experience reduced stand establishment (i.e., not excessively damaged by winterkill), this study will help develop herbicide recommendations to optimize weed management. Weeds such as wild oat and cleavers can be problematic if winter wheat stands are thin. Pyroxasulfone is an experimental herbicide that has activity on wild oat, Bromus spp., cleavers and other broadleaf weeds; however, its efficacy is inconsistent as it is a soil applied herbicide that relies on soil moisture for activation. The objective of this study is to determine the weed control efficacy of pyroxasulfone in managing weeds in optimal and sub-optimal stands of winter wheat. The study was conducted at five locations in Manitoba, Saskatchewan, and Alberta in 2012. Pyroxasulfone was applied pre-seed at rates of 100, 150, 200, and 250 g ai ha-1 to winter wheat seeded at 450 (optimal stand) seeds m-2 and 150 (sub-optimal stand) seeds m-2. Pyroxasulfone weed control efficacy was compared to two post-emergence commercial standards. Herbicide application did not affect plant density indicating that pyroxasulfone did not affect emergence. Visual tolerance of winter wheat to pyroxasulfone was generally low and considered acceptable. Pyroxsulam application resulted in the highest number of heads m-2 (Table 2). It is speculated that spring pyroxsulam application may have resulted in some crop injury; thus, reducing apical dominance; an effect periodically observed with ALS inhibitor herbicides. Table 2. Winter wheat responses to seeding rate and herbicide treatment. Effect / Level Winter wheat Wild oat Cleaver heads density density (no. m-2) Seeding rate (seeds m-2) 150 482 nsa 18 450 602 ns 6 Herbicide Pyroxasulfone 100 542 10 14 Pyroxasulfone 150 536 7 13 Pyroxasulfone 200 540 4 8 Pyroxasulfone 250 520 4 8 Pinoxaden / 557 4 5 fluroxypyr / MCPA Pyroxsulam 595 5 4 Weedy check 506 15 33 a Not significant. Weed densities often were low (mean location densities < 20 m-2). Seeding rate had no effect on wild oat density and pyroxasulfone often reduced wild oat density at rates ≥ 150 g ai ha-1 across all locations (Table 2). An optimal winter wheat stand had lesser wild oat biomass than the sub-optimal stand and all herbicides resulted in lower wild oat biomass than the untreated check only at the location (Lacombe) with greatest wild oat density (results not shown). A pyroxasulfone rate ≥ 150 g ai ha-1 reduced cleavers density at the location (Lacombe) where it was notably present (results not shown). An optimal stand (seed rate of 450 seeds m-2) resulted in a reduction in the pyroxasulfone rate required to reduce broadleaf weed biomass to levels similar to the commercial herbicide standards (Fig. 3). Fig. 3. Interaction of seed rate (plant density) and herbicide application on broadleaf weed biomass (mean of 5 locations) in winter wheat. Winter wheat yield increased by 5% (4.85 to 5.10 Mg ha-1) when seeding rate was increased from 150 to 450 seeds m-2. Herbicide treatment did not affect yield due to low weed densities and the competitiveness of winter wheat. Results from one year of data indicated integrated benefits of spring winter plant populations exceeding 250 plants m-2 along with soil-applied pyroxasulfone to optimizing broadleaf weed control. The experiments will be conducted at the same locations for 2 more years if funding is secured from Growing Forward 2. Sub-activity 1.3 (Test 213) Managing nitrogen when planting winter wheat on barley grain stubble. The major focus of this sub-activity is to determine if nitrogen management recommendations need to be altered when planting winter wheat into barley stubble. There is some concern that heavy trash left after barley is harvested could lead to N immobilization and cause deficiencies in winter wheat. This study was established at Brandon, and at locations in northern (Fahler) and southern (Lethbridge) Alberta in the fall of 2011. Treatments consisted of a factorial combination of four N rates (0, 40, 80, 120 kg N ha-1) and six N application/straw treatments (urea banded at seeding, straw on surface; urea banded at seeding, straw removed; ESN banded at seeding, straw on surface; SuperU banded at seeding, straw on surface; UAN dribble band in spring, straw on surface; SuperU broadcast in spring, straw on surface). Also, N fertilizer rate increased most winter wheat responses, the exceptions being plant density, and kernel/test wt. (results not shown). Of more interest was N/straw management and interactions between the two N management responses. No significant interactions were evident between N fertilizer rate and N/straw treatment for any of the winter wheat responses. Nitrogen/straw management alone did impact some winter wheat responses. Nitrogen/straw management did not affect plant density, grain quality, and N uptake responses. Midseason biomass yield at Lethbridge was greater when UAN was dribble- banded in spring (with barley residue on soil surface) relative to when urea was banded at seeding (barley residue removed); biomass yield was intermediate for the remaining treatments (Table 3). Greenseeker assessments of winter wheat growth in May and June showed that NDVI was affected by N/straw treatment only for the initial three assessments at Brandon. The consistent difference that emerged was that urea banded at seeding (residue removed) consistently resulted in an NDVI equivalent to or greater than other N/straw treatments (Table 3). At Brandon, grain yield was greater where urea was banded at seeding (residue removed) than where SuperU was spring broadcast (with residue applied in the spring) (Table 3). This followed the same general trend as NDVI values observed earlier in the season, suggesting that under the relatively dry conditions experienced in fall 2011 in Manitoba, urea banded at seeding (with residue removed) was more effective than spring broadcast SuperU (with residue applied in the spring) and as effective as the other N/straw treatments employed in this study. The extent to which spring-application of straw may have impacted the plant- available N supply in this treatment is unclear. No differences were evident between the spring broadcast SuperU treatment, and the remaining N/straw management treatments at Brandon, and for all treatments at Lethbridge. Table 3. Winter wheat responses to N/straw management at Lethbridge and Brandon, 2012. NDVIa Location / N/straw Biomass 1 2 3 4 Yield management yield (Mg ha-1) (Mg ha-1) Lethbridge ESN banded at 8.45ab 0.574 0.768 0.843 8.29 seeding SuperU / banded at 8.43ab 0.571 0.773 0.846 8.46 seeding SuperU / spring 8.70ab 0.579 0.791 0.849 8.62 broadcast Urea / banded at 8.41ab 0.559 0.775 0.834 7.82 seeding Urea / banded at 8.01b 0.0553 0.744 0.846 8.30 seeding UAN / dribble banded 8.87a 0.571 0.753 0.833 8.73 in spring Brandon ESN banded at 0.496ab 0.572ab 0.654b 0.664 4.43ab seeding SuperU / banded at 0.525ab 0.583ab 0.654b 0.654 4.32ab seeding SuperU / spring 0.461b 0.549b 0.625b 0.658 4.16b broadcast Urea / banded at 0.469b 0.589ab 0.665ab 0.669 4.56ab seeding Urea / banded at 0.595a 0.646a 0.719a 0.694 4.60a seeding UAN / dribble banded 0.450b 0.554b 0.661ab 0.645 4.42ab in spring a Greenseeker measurements 1, 2, 3 were conducted on May 14, 22, 29, respectively at Lethbridge. Greenseeker measurements 1, 2, 3, 4 were conducted on May 30th, and June 6, 13, and 22nd, respectively at Brandon. Additional site-years of data are required to reach reliable conclusions regarding the impact of nitrogen fertilizer management on winter wheat established on barley stubble. A better understanding of the relative efficacy of conventional and enhanced efficiency N fertilizers, and their interaction with surface crop residues in winter wheat production systems, will be a necessary part of a more effective and efficient management package for winter wheat producers in western Canada. Sub-activity 1.4 (Test 214) Crop growth enhancement through improved residue management strategies. This sub-activity builds upon sub-activities 1.2 and 1.3, but involves a wider array of potential alternative stubbles from barley to camelina. Crop residue management is critical to successful winter wheat production on the Canadian prairies because it controls snow cover, which ultimately protects winter wheat from winterkill. The suitability of different stubble types for winter wheat is determined by the efficacy of stubble in trapping snow and the availability of stubble relative to the narrow window in which winter wheat can be seeded. Field studies were conducted to assess the direct and indirect impacts of surface crop residues from a wide range of crops on the growth, development, yield and quality of winter wheat. The experiment was established at locations In Manitoba and Alberta in 2010 (2011 for one location near Brandon, MB). The stubble-establishment (1st) year treatments included: barley (swath removed); barley (swath removed, barley seeds broadcast at a rate of 400 seeds m-2); barley (combined to retain straw and chaff); canola (swathed and combined to retain straw and chaff); dry pea (desiccated and combined, with winter wheat seeded between stubble rows of the cereal preceding the pea crop); dry pea (desiccated and peas pulled rather than cut, with winter wheat seeded between stubble rows of the cereal crop preceding the pea crop); spring-seeded camelina (combined to retain straw and chaff); spring-seeded camelina (swath removed); fall-seeded camelina (combined with straw and chaff retained); and fall-seeded camelina (swathed with residue removed). Camelina treatments were not included at all locations. Winter wheat was seeded into the various stubble treatments in the fall of the establishment year. The snow trapping potential (STP; stubble height in cm x stubble stems per square meter) / 100) of barley was considerably > 20 (considered adequate) whereas STP for canola or pea was consistently < 20 regardless of the residue management practices employed (Table 4). Spring camelina inconsistently resulted in STP that was adequate, but levels of STP were not as high as barley. Table 4. Snow trapping potential responses to stubble treatment. Stubble treatment BrandonA BrandonB Beaverlodge Lacombe Lethbridge STP - Snow trapping potential Barley- swath removed 98 aa 70 a 76 a 103 a 31 a Barley- swath removed, then barley seeds 111 a 61 a 69 ab 119 a 32 a broadcast Barley- combined to retain straw and chaff 93 a 66 a 62 b 113 a 29 a Canola- swathed and combined to retain straw 12 b 9 bc 13 c 17 b 8 b and chaff. Dry pea- desiccated and combined; winter wheat 12 b 5 c 11 cd 13 b seeded onto pea rows Dry pea- desiccated and peas pulled rather than 13 b 6 bc 6 cd 28 b cut Camelina (spring) - combined to retain straw and 38 b 19 bc 4 cd 22 a chaff Camelina (spring) - swath removed 41 b 24 b 8 cd 24 a Camelina (fall) - combined to retain residue -- -- 2 d Camelina (fall) - swathed with residue removed -- -- 6 cd a Values within a column followed by the same lettter are not significantly different based on Tukey's multiple comparison procedure. Seeding winter wheat after canola reduced winter wheat stands compared to seeding winter wheat after barley, pea or spring-seeded camelina at 2 of 3 locations (Table 5). It is likely that stand reductions for canola stubble contributed to the lesser winter wheat yields for canola stubble at Beaverlodge (Table 5). Seeding winter wheat after pea, but between the stubble rows from the cereal crop preceding the pea crop, resulted in similar winter wheat stands and greateer grain yields than seeding winter wheat after barley at all locations. Estimated grain N uptake was greater for winter wheat after pea than after barley suggesting that differences in available N supply may have contributed in part to observed yield differences (Table 5).