Kutcher: Optimizing Canola Production, Pest Implications of Intensive Canola Rotations

Date: March 31, 2008
Term: n/a
Status: Completed
Researcher(s): H.R. Kutcher and S. Brandt, Agriculture and Agri-Food Canada
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: MCGA

Project Summary

Flexibility in rotation planning allows canola and field pea producers to adapt to changing management practices and marketing opportunities. Current recommendations are to follow a one in four year rotation for canola or field pea on a particular field. The objective of this study was to determine the consequences of more intensive rotations of these crops using current technology: disease resistant, herbicide tolerant varieties and new fungicides for disease control.

The study was conducted at Scott and Melfort, SK, which represents the range of climatic variation in the parkland area of the prairies. A four replicate split-plot experiment was established at each site with treatments that consisted of rotations of continuous canola and field pea to rotations that contained these crops every 2-, 3-, and 4-years with wheat and flax. Two varieties of canola were included, an herbicide tolerant, blackleg resistant hybrid (Invigor 5030 or 5020) and an open-pollinated, blackleg susceptible conventional herbicide type (Westar). Sub-plots were fungicide treatments where we attempted to control sclerotinia stem rot in canola and mycosphaerella blight in field pea. Blackleg of canola and mycosphaerella blight of field pea, were the major pest problems that occurred in all years.

These diseases, as well as the prevalence of weeds, were greater in more intensive rotations of canola and field pea. In canola, the use of a blackleg resistant variety in a 4-year rotation provided the most effective disease control. Yield of both canola varieties increased with length of rotation, although there was little difference among rotations of 2 or more years for Invigor varieties, but yield of Westar continued to increase as the frequency in rotation decreased to once in four years.

Yield of field pea was reduced in the continuous rotation compared to other rotations, but the difference among rotations of 2 or more years was small. Fungicide application resulted in an 11-16% yield increase of field pea at some site-years, and an increase of 48% at one site-year, but no yield increase at other site-years. Fungicide application did not increase yield of wheat at either location in 2004 or 2006, but did result in a 27% yield increase at Scott and a 13% increase at Melfort in 2005. Yield and sometimes quality of wheat were reduced when wheat was grown on Invigor canola stubble compared to Westar stubble. This is an indication that wheat crops following highly productive canola crops, such as the Invigor varieties used in this study, may require greater levels of fertility than wheat grown after less productive canola crops.

The results clearly indicate the importance of crop rotation to manage diseases and weeds of canola and field pea, and for the former, the importance of genetic resistance in the control of blackleg.

Full Report PDF: Optimizing Canola Production, Pest Implications of Intensive Canola Rotations