Harker: Factors Influencing Canola Emergence
Date: April 2013
Term: 3 years
Status: Completed
Researcher(s): K.Neil Harker, J.T. O'Donovan, Agriculture and Agri-Food Canada (AAFC), Lacombe AB, Robert Blackshaw, AAFC Lethbridge, AB, Eric Johnson, AAFC, Scott SK, Guy Lafond, Bill May, AAFC Indian Head
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: n/a
Project Summary
Canola seed is a substantial input cost and poor canola stand establishment is a continuing concern for canola growers. On average, only 50% of planted seeds emerge; even when germination is above 90%. Researchers with Agriculture and Agri-Food Canada (AAFC) led a three-year project to study factors affecting canola emergence and quality, including seed type, seeding speed and seeding depth to determine if seeding slow and shallow would enhance economic returns for growers. Overall, the results showed that canola growers can improve canola emergence density by seeding canola at a depth of 1 cm. Seeding speed influenced canola variables to a much smaller degree than seeding depth.
Canola seed is a substantial input cost and poor canola stand establishment is a continuing concern for canola growers. On average, only 50% of planted seeds emerge; even when germination is above 90%. Poor canola emergence and stand uniformity lead to agronomic problems that can reduce canola profitability. Resolving the low emergence problem has the potential to significantly improve grower decision-making at seeding and net returns at harvest.
Researchers with Agriculture and Agri-Food Canada (AAFC) led a three-year project to study factors affecting canola emergence and quality, including seed type, seeding speed and seeding depth and to determine if seeding slow and shallow would enhance economic returns for growers.
Direct-seeding experiments were conducted at four sites in western Canada from 2008 to 2011, including Lacombe, Lethbridge, Scott, and Indian Head. Data was collected for 10 of 12 possible site years. Flooding, hail and frost prevented data collection for two site years. Hybrid or open-pollinated glyphosate-resistant canola was seeded at speeds of 4 or 7 mph and at depths of 1 or 4 cm in replicated trials. Data collection included canola emergence density, flowering dates and durations, crop maturity, canola yield, oil and protein content, and percent green seed.
The study results showed that canola growers can improve canola emergence density by seeding canola at a depth of 1 cm. Under moist conditions, average canola emergence improved dramatically as seeding depth decreased from 4 to 1 cm. Canola emergence averaged 35% at seeding depths of 1 or 4 cm when precipitation levels were low. Emergence levels increased to an average of 66% when precipitation levels were high and when seeding depth was at 1 cm.
Figure 1. The effect of seeding depth and seeding speed on hybrid canola (‘7145RR’) emergence density (plants m-2). Means were estimated based on the PROC PLS analyses, which grouped sites according to environmental conditions; in this case the dominant factor was precipitation levels surrounding the time of seeding.
Seeding speed influenced canola variables to a much smaller degree than seeding depth.
Figure 2. Hybrid canola (’71-45RR’) seeded at 4 mph at depths of 1 (left) and 4 (right) cm.
Photo credit: K. Neil Harker, Lacombe Research Centre, 2007.
Seeding at 1 cm versus 4 cm also decreased days to emergence, increased canola ground cover, decreased days to flowering and days to maturity and tended to decrease green seed levels. Canola compensates for sparse or weak canopies, but this can lead to a delay in crop maturity, increasing the potential for heat stress and green seed grade losses. Improved canola emergence density facilitates competitive crop canopies that require fewer herbicide applications and, therefore, reduce selection pressure for weed resistance to herbicides. Relatively high canola stand densities can also improve the ability of canola to successfully tolerate and accommodate biotic and abiotic stress.
zANOVA P values. Seeding density was 150 seeds m-2.
In the comparison of hybrid versus open-pollinated cultivars, the agronomic performance of hybrid canola, including seed yield and quality was usually superior to open-pollinated canola, but there was no difference in emergence density between the two cultivars. However, the hybrid cultivar emerged 1 day earlier, grew faster and covered the ground more quickly than the open-pollinated cultivar. These are important results from a crop-weed competition and herbicide-resistance management standpoint.
Scientific Publications
Harker, K. N., J. T. O’Donovan, R. E. Blackshaw, E. N. Johnson, G. P. Lafond, and W. E. May. 2012. Seeding depth and seeding speed effects on no-till canola emergence, maturity, yield and seed quality, Can. J. Plant Sci. 92:795-802.
Full Report PDF: n/a