Strip-Till Series: Fertilizer and Cover Crops Part 3 of 3
By Alyssa Gingras
In a strip-till system, most, if not all, of the fertilizer gets placed in the strips. If using shanks, it can be banded or placed in the seed trench, but be careful of seed burn. With coulters, it is more broadcast and incorporated. This is great for 2 reasons; 1) the fertilizer is placed where the roots will have access to it and 2) it doesn't get left on the surface, where it is more prone to loss by runoff and volatilization. Because of this, fertilizer use efficiency is greatly increased when compared to whole field broadcasts, especially in no-till, where it won't be worked in. Fertilizer is only placed where it is needed and losses to the environment are reduced. While fertilizer use efficiency is increased, this doesn't mean you can lower your rates, but it does mean you are wasting less of what you paid for. While fertilizer can be put down through the strip-tiller with liquid and solid options, it can also be done through the planter, so there is more flexibility in your application timing.
Incorporating Cover Crops into Strip-Till
If you're looking to get more ambitious, think about adding cover crops to your rotation and strip-till system. If you do chose to seed cover crops, it is best to seed as soon as you can after winter wheat harvest. Some of the benefits of using cover crops include - Potential for an increase in nitrogen use efficiency, with the cover crop scavenging leftover N from the previous crop - Improved soil health and structure, with more roots, organic matter and soil cover - Potential pollinator and wildlife food and habitat, depending on specie(s) chosen Some of the negatives include: - Cost of seed, labour, and equipment - Time needed for seeding - Time needed for termination and consequences of a poorly or late terminated stand, if you chose overwintering species - Variable stand establishment, if broadcasting Some considerations to make if adding cover crops: - If using oats, seeding rates should be 40-45lbs/ac, a cover crop shouldn't be too heavy or it will become a problem - Do you want a simple or complex mix? If just beginning, it's usually best to start with one or two species, but it also depends on what your cover crop goals are - What species should you use? Again, it depends on what your cover crop goals are, but an oat/pea mix, tillage radish, and cereal rye are commonly used species. If you have fall strips, cereals are a good option for erosion control.
- How are you terminating the crop? If you're using species that will winterkill, such as oats and peas, it's not a concern, if you use an overwintering species, such as cereal rye you will need to terminate it either in the fall or early spring. Some people choose a fall burndown so there is less to control in the spring but there is often volunteer wheat regrowth that will overwinter. If you want the full benefit of an overwintering cover crop, leave it until spring and use pre-plant or pre-emerge herbicides to terminate.
- When are you terminating the crop? Again, it depends on your cover crop goals and maybe time availability. Do you have time in the spring? Are you going to cut it for feed? Are you planting green? What crop is going in after? Generally, we do want it dead by the time the crop new comes up and with species like cereal rye, considerations should be made regarding allelopathy and moisture availability.
Taking cover crops a bit further in our strip-till system lends perfectly to bio strip-till. Here, alternative rows of cover crops are planted to mimic strip-tillage. For this, you would have two mixes, the tillage/crop row mix and the wheel track mix between the rows. Tillage/crop row species considerations: - Should be winterkilled and break down over winter/early spring - Should have low lignin/C:N; don't want to tie up nitrogen, most legumes are a good option - Select cool and warm season species to take advantage of late august heat as well as fall temperatures Wheel track mix species considerations: - Should have some overwintering species, to get the benefits of a live cover crop during the winter and spring. Some of these include weed suppression, soil, nutrient and water holding capacity, drying wet soil in spring by taking up water. These rows will also better support equipment in wetter conditions. - Should have more lignin/higher C:N ration content, which is better for building organic matter, typically cereals. - Need to be terminated with herbicides in the spring pre-plant or pre-emerge - Added bonus of being a trap crop for slugs
For more information
Watch the 3-part Strip-Till Speaker Series by Food and Farm Care Ontario here: https://fieldcropnews.com/2020/12/strip-till-speaker-series-now-online/