By Tori Waugh
In the compaction recovery with cover crops tier two applied research project, we’re seeking to understand the relationship between the use of cover crops in a rotation and the alleviation curve after a compaction event. Knowing more about the tools available to farmers to alleviate compaction is important for the same reasons that prevention is important. Compaction can lead to decreased water infiltration and water holding capacity, increased soil erosion, reduced yields and nutrient uptake, increased input costs, reduced root growth and rooting depth.
In the research project, we began with installing compaction treatments. Farmer participants installed two solid blocks of compacted soils by running fully loaded equipment in soil moisture scenarios that would guarantee compaction. The treatment, being a worst-case scenario treatment, was installed wheel -to-wheel at two no-till sites in Bruce county. In the spring, we will be installing similar plots in historically tilled sites for comparison. We have been accepting a variety of management schemes and equipment, to better understand cover crops and compaction in farming systems, as opposed to in isolation.
Once the compaction blocks are installed, we then run into our secondary treatment: cover crops. With farming systems as our lens, we have also been accepting all approaches to cover crops into our plots. We accept whatever practices are normally employed by the farmer as the control and then do the opposite as the treatment. For example, both our current no-till compaction plot participants normally use cover crops in their rotation, so their treatment plots were two blocks that were left with no cover crops. The cover crop (or “no cover crop”) blocks are of the same size as the installed compaction plots but offset by half a plot. This lets us look at two repetitions of compacted-with-cover-crops, compacted-with-no-cover-crops, uncompacted-with-cover-crops and uncompacted-with-no-cover-crops.
We have purchased two penetrologgers as part of this project to allow a variety of users to measure compaction in the plots as well as in other projects. These will be used to measure compaction with a randomized sampling scheme, while still having record of where samples were taken, should the data produced prove inconsistent. These also provide usage feedback to ensure consistency between users, a common issue with common penetrometers. We have ensured that the pentrologgers will be used to the benefit of Ontario Agriculture by training multiple OMAFRA and OSCIA staff on their use, so that they may be used in a wide variety of projects posed to serve Ontario Agriculture. We have also engaged the Bruce county community with in-field tour stops and workshops aimed at sharing the findings of this project and attracting more participants to the projects.
Our initial findings with the compaction plot are limited, with the resulting compaction possibly being buffered by the existing soil conditions and best management practise in place. It’s possible, too that the soil was just too wet, until it was too dry. Our attempts at taking penetrologger readings were impacted by soil moisture, in much the same way that planting was affected in 2019. Whether compaction did not actually result from our compaction installations or the soil moisture was too high, will be defined in our compaction measurements this spring. One parameter that we were able to successfully measure in the 2019 season was yield impacts, of which, we found none. There was not a significant difference between plots.