Does strip-till belong in your farming system?
Monday, August 5, 2013
There are both advantages and challenges to strip-till. But following these rules will give you a better chance of success
by KEITH REID
A farmer recently asked me about where strip-till might fit on his farm. It seemed like a pretty simple question, but it got me to thinking about how to use strip-till as a system to maximize its advantages while minimizing the risks that can lead to inconsistent results.
What is strip-till? As the name suggests, strip-till only works a narrow strip where the crop will be planted, leaving the area between the rows undisturbed. (Don't confuse this with "strip cropping," which is alternating strips of row crops and close-seeded crops planting across slopes.)
There are a number of advantages to this approach, which should combine the best of no-till with the best of conventional tillage. It provides very good erosion control, since most of the ground remains covered with crop residue. At the same time, the cultivated soil in the strip will dry out and warm up faster than the residue-covered soil, avoiding the delay in crop emergence and slow early growth that has plagued many no-till fields. It requires fewer passes through the field than a conventional system, so there are significant savings in time, fuel and equipment maintenance.
Strip-tilling equipment often has the capacity to band fertilizer while the strip is being worked, completing two tasks at once. Because the planting strip has been loosened, conventional planting equipment can be used with little or no modification, instead of requiring a no-till planter. Crop yields are often, but not always, similar to those in conventionally tilled fields.
Challenges of strip-till. Why, then, isn't everyone strip-tilling? Unfortunately, not every farmer who has tried strip-till has been successful, for a number of reasons.
The strip may not have been formed properly so that, instead of drying out sooner than the surrounding soil, it created a hollow that held water. The strip-tiller may have left the soil too "cloddy," so there was poor seed-soil contact. The strips, if they are oriented up and down a hill, can actually encourage erosion by forming channels for water to run down during snowmelt or heavy rain. Heavy residue may have interfered with the operation of the strip-tiller, or undulations of the soil surface may have left areas where the strip-till unit was out of the ground instead of doing its job.
None of these challenges are insurmountable, but they can be enough to discourage someone who is experimenting with strip-tillage. After all, it would mean the purchase of another piece of equipment that will only be used for one crop in the rotation.
A systems approach to strip-till. If you are going to make strip-till a successful part of your operation, there are a number of things you can do to increase your chances of success. Remember that they are all interconnected, so you cannot simply change the tillage implement and expect things to work the same as they did before:
Pick the right field. Acidic soils, poor drainage, low fertility or ruts and hollows will all reduce the benefits of strip-tillage as much or more as they will other tillage systems, so make sure these fundamental issues have been corrected before heading to the field with the strip-tiller. Rotating crops will also have greater benefit in strip-till than in conventional tillage.
Wait for the proper soil conditions before the first pass. Don't work the soil when it is too wet.
Ensure the unit is set properly. The soil after tillage should be crumbly without any large clods or fissures, since there won't be any secondary tillage to fix the shortcomings of the first pass. The strip-tiller should leave a small ridge, so that when the soil settles over winter it doesn't leave a trench to hold water where you are trying to plant.
Travel across the slope rather than up and down.
A guidance system with RTK makes the job easy.
Make sure you are applying the fertilizer you need, at a time when it won't be lost. Banding P and K in the fall is fine (as long as you include some P near the seed at planting), but don't apply N until close to the time when the crop needs it.
Assess conditions before planting in the spring. Does it need a second pass? As with conventional tillage, don't try to plant into soil that is too wet. Weed control may present special challenges, since the weed species and the time they emerge may be different on the strip-tilled soil than in the untilled soil between rows. Pre-plant burn-down and residual herbicides may both be required for controlling weeds, as well as regular scouting to track weed emergence.
Following these rules won't guarantee success, but they will take you a long way towards avoiding failure as you learn this new system. BF
Keith Reid is manager (Eastern Canada, Soil Nutrient and GHG Management) Agriculture and Agri-Food Canada, Guelph.