A meta-analysis of small-plot trial data to examine the relationship between crop development and environmental conditions in canola
Term: 1 year ending August 2023
Status: Complete
Researcher: Christiane Catellier, IHARF
SaskCanola Investment: $7,500.00
Total Project Cost: $15,000.00
Funding Partners: WGRF
Grower Benefits
This research confirmed that the field emergence values frequently observed in canola production, in the range of as low as 20-30% to as high as 80-90%, can be explained by measurable management and environmental variables.
Seeding date and average air temperature before and after seeding were the most influential variables and appeared to be related to soil moisture.
Seeding rates may need to be increased when seeding at a later seeding date, when high average temperatures or low precipitation are observed before seeding or expected after seeding.
Project Summary
Canola emergence rates vary widely with management practices and field conditions; thus, it is difficult to know the specific seeding density required to achieve the optimum plant population for maximizing canola yields. It would be beneficial for growers to know the precise range of emergence rates that can be expected based on their practices as well as the local environmental conditions.
The objective of this project was to utilize archived small-plot canola agronomic trial data and corresponding regional weather data to conduct a meta-analysis to examine the relationship between environmental conditions and canola emergence.
Meta-analysis is a powerful analytical tool where many independent data sets can be combined into a single analysis to provide a more accurate, wide-ranging interpretation of a research topic. The greatest benefit of meta-analysis for agronomic research is the greater statistical power that results from increased replication across a greater diversity of environments. The combined data set comprised agronomic and environmental data from 12 different projects conducted across a total of 47 site-years in Saskatchewan and Manitoba from 2013-2022. Single-variable regression and two-variable interaction models with mixed effects were used to examine the effects of individual management and environment variables and their interactions on the percent emergence of canola.
The overall average percent emergence was 60.7%. Seeding density, seeding date, seed-placed fertilizer, and average pre- and post-seeding air temperature all had negative effects on the percent emergence of canola, while pre- and post-seeding precipitation had positive effects on emergence. These effects were mostly as expected, apart from negative effects of seeding date and temperature which are likely related to soil moisture. The effect of seed-placed fertilizer (N, P, and/or S) on canola emergence varied with seeding date, pre-seed precipitation, and post-seeding temperature. Figure 1 shows the effect of seed-placed N on canola percent emergence. The effects of seeding density varied with seeding date, pre-seed precipitation, and pre-seed temperature. Interacting effects between management and environmental variables were more likely under more ideal conditions of the most influential variables, specifically earlier seeding dates, lower average temperatures, and higher precipitation.
Figure 1. The effect of seed-placed N on canola percent emergence varied with seeding date (left), pre-seed precipitation (middle), and average pre-seed temperature (right).