By John Ippolito PAg., Regional Crop Specialist, Kindersley
The 2016 harvest season was very challenging in West Central Saskatchewan and unfortunately, we are not finished dealing with some of those challenges. Along with crop that still has to be harvested, there are ruts from fall operations and areas that will simply be compacted.
Field ruts are normally deeper than a couple of inches and restricted in width to the size of the tire that created them. The normal practice for filling in these would be tillage with either a cultivator and harrows or a tandem disc implement. Ideally, the depth of cultivation should be slightly deeper than the depth of the rut. However, with deep ruts this may mean tillage into the B horizon. This is not recommended as mixing of the A and B horizons would have long term effects on the top soil quality. Tillage to fill in ruts should be limited to the width of the rutted area if at all possible.
There may be a temptation to use something deeper, such as vertical tillage to not only fill in ruts but, break up some deeper compaction. This is not likely required and not recommended. Saturated soils have all the pore spaces filled with water which means they are at low risk for compaction. Ripping to fracture compacted soils only works when the soils are dry and therefore, would not be recommended until those soils have dried out.
Probably one of the largest concerns for this spring on clay soils in particular will be slight depressions, created by wheel traffic either last fall or if harvest must be completed this spring. These depressions are going to create challenges in terms of maintaining uniform seeding depth across the width of the drill. Independent opener drills will handle this better, but are not an option for everyone. Seeding across these tracks at a slight angle is likely preferred to seeding parallel to them. There will still be openers that are not at the correct depth, but this will avoid the situation where the whole drill is at an incorrect depth with depth control wheels following the depression. Many producers are already using this practice and it likely will increase for 2017.
The worst case scenario for soil compaction is implement traffic when soils are close to field capacity. At field capacity the small pore spaces are filled with water, but the large pores still contain air. Traffic will squeeze this air out and the soil particles stick together with the moisture that is present resulting in compaction. It is also important to note that 80 per cent of compaction occurs in the first implement pass. With this in mind, producers may wish to consider seeding some land prior to worrying about harvesting the rest this spring. By delaying the harvest on those acres, the soils can dry to below field capacity which should reduce soil compaction from the harvest operation.
More information can be found at Canola Watch – Dealing with ruts.