Byron Irvine

Canola seed yield and phenological responses to plant density

Optimal plant density is required to improve plant phenological traits and maximize seed yield in field crops. In this study, we determined the effect of plant density on duration of flowering, post-flowering phase, and seed yield of canola in diverse environments. The field study was conducted at 16 site-years across the major canola growing area of western Canada from 2010 to 2012. The cultivar InVigor® 5440, a glufosinate-resistant hybrid, was grown at five plant densities (20, 40, 60, 80, and 100 plants m-2) in a randomized complete block design with four replicates. Canola seed yield had a linear relationship with plant density at 8 of the 16 site-years, a quadratic relationship at 4 site-years, and there was no correlation between the two variables in the remaining 4 site-years. At site-years with low to medium productivity, canola seed yield increased by 10.2 to 14.7 kg ha-1 for every additional plant per square metre. Averaged across the 16 diverse environments, canola plants spent an average of 22% of their life cycle flowering and another 27% of the time filling seed post-flowering. Canola seed yield had a negative association with duration of flowering and a positive association with the days post-flowering but was not associated with number of days to maturity. The post-flowering period was 12.7, 14.7, and 12.6 d (or 55, 68, and 58%) longer in high-yield experiments than in low-yield experiments in 2010, 2011, and 2012, respectively. We conclude that optimization of plant density for canola seed yield varies with environment and that a longer post-flowering period is critical for increasing canola yield in western Canada.

Reducing the risks of in-crop nitrogen fertilizer applications in spring wheat and canola

Nitrogen is the most limiting nutrient in crop production on the Canadian prairies. There is great interest in managing it more effectively for environmental and economic reasons. Our objective was to study the effectiveness of using different proportions of recommended nitrogen rates at seeding with the balance at different crop growth stages to minimize the risks of potential yield losses from in-crop nitrogen applications in spring wheat and canola. The field trials with wheat were conducted at three locations from 2003 to 2006 and at two locations for canola from 2004 to 2006. The treatments consisted of applying 100, 67, 50, 33 or 0% of the targeted N rate at seeding using urea in mid-row bands and the balance in-crop at the 1.5, 3.5 or 5.5 leaf stages in spring wheat and at the 5-6 leaf stage, bolting or start of flowering stage in canola using surface dribble band of liquid urea-ammonium nitrate. With spring wheat, applying 33% of the recommended N rate at seeding with the balance in-crop resulted ...

Seed Ethanol Emission and Radicle Protrusion are Better Measures of Canola-Seed Vigor Than Standard Germination

Results of a seed vigor test based on ethanol emission (EE) were compared to rate of emergence (Em50), extent of emergence, seedling mass, and leaf area for 64 lots of open-pollinated and hybrid canola (Brassica napus L.) seed in field plots. The EE test was evaluated against other measures of seed vigor, specifically days to 50% radicle protrusion (R50), 2-d radicle protrusion (R2), seedling fresh mass in hydroponics, cold germination, and a vigor index. Correlation coefficients for R50, R2, and EE versus Em50 were ≥ 0.8 and consistently better than those for standard germination (SG, normal seedlings) for open-pollinated and hybrid propagation types in both the 80%–100% and 90%–100% SG ranges. In contrast to Em50, other aspects of field vigor were not well correlated with vigor tests. It is suggested that EE and R2 are suitable for providing seed quality information to supplement SG results.

Economic and Risk Effects of Rotation Based on a 14-Year Irrigated Potato Production Study in Manitoba

Crop rotations can be used to optimize economic return by preserving or enhancing soil quality and reducing pest pressure. A field experiment consisting of six rotations of potato with canola (P-C), wheat (P-W), canola-wheat (P-C-W), oat-wheat (P-O-W), wheat-canola-wheat (P-W-C-W), and canola underseeded to alfalfa-alfalfa-alfalfa (P-C(A)-A-A) organized in a Randomized Complete Block Design was established on a clay loam soil in Manitoba, Canada and monitored for fourteen years to assess the relative economic performance of potato in each rotation. A stochastic budget based on returns and risk of returns trade-offs was used to determine each rotation’s profitability. While differences in average annual net income of all crops between rotations were not significant, the P-C-W rotation was the most stable. Despite the economic advantage of P-C in the first two cycles, longer P-C-W or P-C(A)-A-A rotations are recommended, as two-year rotations increase plant disease and decrease economic viability in the long run.ResumenLas rotaciones de cultivos pueden usarse para optimizar la recuperación económica mediante la preservación o aumento de la calidad del suelo y en la reducción de presión de plagas. Se estableció un experimento de campo consistente en seis rotaciones de papa con canola (P-C), trigo (P-W), canola-trigo (P-C-W), avena trigo (P-O-W), trigo-canola-trigo (P-W-C-W), y canola mezclada con alfalfa-alfalfa-alfalfa (P-C(A)-A-A) organizado en un diseño de bloques completos al azar, en un suelo arcillo-limoso en Manitoba, Canadá, y monitoreado por 14 años para evaluar el comportamiento relativo económico de papa en cada rotación. Se usó un presupuesto estocástico basado en recuperaciones y en el riesgo de compensaciones de recuperaciones para determinar la redituabilidad de cada rotación. Mientras que las diferencias en el promedio anual de ingresos netos de todos los cultivos entre rotaciones no fueron significativas, la rotación P-C-W fue la más estable. A pesar de la ventaja económica de P-C en los primeros dos ciclos, se recomiendan las rotaciones más largas P-C-W o P-C(A)-A-A, ya que las rotaciones de dos años aumentan enfermedad de la planta y a la larga disminuyen la viabilidad económica.