Vertical Tillage and Burning in Flax Straw Management and Effects on Soil Nutrient Levels, Physical Parameters and Yield in South-Central Saskatchewan.

Vertical tillage and burning in flax straw management and effects on soil nutrient levels, physical parameters and yield in south-central Saskatchewan

Cory Fatteicher, Raul Avila, Tom King, Jordan Wiens, Jeff Schoenau and Bing Si

¹Department of Soil Science, University of Saskatchewan, Saskatoon, SK, CANADA S7N 5A8

Flax is commonly grown on the prairies in Saskatchewan, Canada and farmers struggle with management of flax straw post-harvest as the residue can make direct seeding in the following spring difficult. The straw is often raked and burned in fall or early spring but this can be an undesirable loss of carbon and nitrogen from the system. An alternative is the use of vertical tillage implements to incorporate and spread the flax straw post-harvest. The purpose of this study was to evaluate the effects of raking and burning versus vertical tillage of flax stubble on 1) soil nutrient levels, 2) soil structural attributes and 3) yield of wheat following a flax crop at a site in the brown soil zone in south-central Saskatchewan. The vertical tillage implement used has round concave disks similar in design to a tandem disk, along with a rolling “basket” that follows the discs. At high travel speeds (greater than 10 km hour), the rolling basket throws and mixes the loose soil brought up by the discs, incorporating the residue and smoothing the surface. Blocks within the study site were divided into two sections to evaluate the effect of raked and burned flax straw versus vertical tillage, with no residue management as the control. Significant differences were found in soil nutrient levels in the raked and burned areas as compared to the control. Raking tended to increase soil organic carbon concentrations in the zones where the raked material accumulated. Raking and burning the previous year’s flax stubble had no apparent effect on 2016 wheat crop yields, compared to raking only of the flax stubble and the control (non-raked and non-burned) treatments. There was a trend towards the vertical tilled plots and the control having a slight yield advantage as compared to the raked and burned treatment.