Stubble Management Effects on Canola Performance Across Different Climatic Regions of Western Canada.

Previous research in the most arid region of the Canadian Prairies has shown that stubble cut tall the previous year can improve performance of the following canola crop. It is a relatively simple, inexpensive procedure to cut cereal stubble at a taller length. If this practice can increase canola yields, it would provide a means to boost production and economic returns without adding extra pesticides or fertilizers. The main objective of this research was to determine if tall stubble would create significant benefits for canola performance across a broad range of climatic conditions typically experienced in western Canada. The study was conducted over 11 site-years during 2011 and 2012 across the breadth of the Canadian Prairies. At each site, tall stubble (50 cm) treatments were compared to short stubble (20 cm) treatments. At some sites the stubble experienced lodging and damage which created an unintended comparison. A comparison of the damaged and intact stubble treatments showing inconsistent results in regards to germination rate and plant population, however the biomass and yields in damaged stubble, either short or tall, were significantly lower than that in the intact stubble. It is postulated that the soil under the damaged stubble would have warmed and dried more slowly, which was detrimental in the wet spring conditions experienced during the study and was the reason for the lower biomass and yield. At study sites where both the tall and short stubble treatments remained intact, there was a significant yield advantage in the tall stubble. It is postulated that where the stubble stayed intact, tall stubble lowered evaporation more than short stubble which reduced moisture stress during the dry conditions that occurred in the mid to late growing season during the study. Thus, the practice of leaving tall cereal stubble in the fall prior to growing canola is most suited to those growing regions where moisture stress occurs more frequently than excess moisture. Keywords: stubble management, canola yield