Performance Story: Effect of Cereal Crop Residue Distribution on the Following Year’s Canola Emergence and Yield
Residue management is a significant challenge for producers on a year-to-year basis. Uneven and poorly distributed residues can lead to many complications for producers, such as uneven seed depth the following spring, blocked drill openers, and uneven plant stands and emergence. Because Western Canadian producers often seasonally rotate wheat and canola crops, it is important to have a better understanding of how wheat residue management can affect the emergence of canola in a rotation. The objective of this research was to analyze canola emergence and yield based on different wheat residue harvest management strategies.
The project evaluated three years of data beginning in the fall of 2017 and ending in the fall of 2020. Each site year (Year 1- Delmas, Saskatchewan; Year 2 - Saint Front, Saskatchewan; Year 3- Nipawin, Saskatchewan) started with a wheat harvest comparing two residue distribution strategies (good distribution vs. poor distribution), followed by post-harvest treatments of heavy harrowing as well as tillage with a high-speed disc. These treatments were compared to a check treatment without a harrow or tillage treatment applied. To represent accurate on-farm management techniques, a full quarter section of land was utilized in each of the three years to accommodate real-world equipment and management techniques. Four replications of each treatment were used to mitigate potential spatial variability differences (e.g., soil zones and climatic differences) as well as past management practices. The post-harvest equipment used in the study included the original equipment manufacturer (OEM) and aftermarket (AFT) choppers, where the OEM straw chopper was configured to represent poor (uneven) residue distribution. During the following spring, sites were planted to canola and managed to match producers’ practices. Canola plant emergence as well soil moisture and temperature were measured during the growing season and yield data for each treatment was measured in the fall.
The results for the three trial years indicate that implementing AFT choppers provided a more even field finish than the poorly set OEM choppers. The AFT choppers also provided smaller fractioned residue than the OEM. The OEM chopper left most of the residue directly behind the chopper, which caused a strip pattern through the fields. When comparing the straw fraction sizing, the OEM typically produced a larger amount of coarse residue (particles longer than 3.0 in. [8.0 cm]), where the AFT produced a larger amount of fine residue (less than 0.5 in. [1.3 cm]). Post-harvest treatments (heavy harrow and tillage) aided in spreading the OEM residue clumps and provided minimal (visual) difference in AFT treatments.
When comparing the canola emergence between the treatments (the two choppers as well as the post-harvest treatments), the results varied by year with few significant differences over the three years. In Year 1, there was no significant differences found in any of the emergence data. In Year 2, during the first plant count, there was little to no emergence due to a dry spring. However, in the second plant count, the check and harrow treatments had significantly higher emergence than the tilled treatment. In Year 3, the only significant measurement of note was during the second plant count where the OEM had a significantly higher plant count than the AFT when measured outside the chaff row (chaff row referring to directly behind the combine chopper). This could have been caused by the minimal amount of residue located outside the chaff row; a higher concentration of residue was found directly within the chaff row
itself. Aside from these few significant differences, the remaining data proved to show no significant differences in emergence.
Soil moisture and temperature data was gathered during the plant count timings again with few significant differences. It was found that the tillage treatments generally resulted in higher soil temperatures across all treatments. The soil moisture data differed across years with Years 1 and 2 displaying higher moisture in the AFT treatment, and in Year 2 where the OEM displayed higher soil moisture.
The yield data across the treatments also showed few significant differences. Each treatment was weighed, with the yield being corrected to a 10% seed moisture content. In Year 1, there was no significant yield difference across chopper type or in the post-harvest treatments; however, the harrowed treatments displayed a lower seed moisture content than the check and tilled treatments, indicating a faster dry down. In Year 2, there was again no significant difference in yield across chopper type; however, the check treatment yield was significantly lower than the harrow and tilled treatments. The harrow and check treatments were shown to have significantly lower seed moisture than the tilled treatment. In Year 3, the AFT chopper treatments indicated significantly higher canola yields than OEM, with no significant differences found in the post-harvest treatments. There were no significant differences found in the seed moisture across all treatments. These results indicate that producers can benefit by implementing a residue management practice (whether it be through an even chopper distribution or by harrowing or tillage).
Although the results did not show many significant differences over years, proper residue management is recommended for a good plant stand, ease of in-field management, and a good canola harvest outcome. The results from this study displayed many notable impacts of the different residue management practices. Without an even residue distribution pattern, there are risks associated with both bare ground as well as clumping behind the chopper. Bare ground can lead to erosion, and clumped residue that does not break down could lead to an increase in disease, such as Blackleg (Canola Council of Canada, 2021). Future work on this topic may consider analyzing results based on longer crop rotations and tillage treatments as well as other factors that may affect the treatments (e.g., soil microbial community, disease pathogen levels, etc.).
Reference:
Canola Council of Canada. (2021). Blackleg . Retrieved from Canola Encyclopedia: https://www.canolacouncil.org/canola-encyclopedia/diseases/blackleg/