Brian Nybo is a researcher with the Wheatland conservation area in Swift Current, Sask., and also a farmer. He’s been researching the best ways to take forage crops out of production, and has set up a demonstration at the research station near Swift Current.
“It can be fairly difficult,” he told farmers at the Agri-ARM research update at the Crop Production Show in Saskatoon in January. “There are some challenges involved.”
“A lot of producers are taking forages out of production for a number of different reasons.” This includes switching to annual crops, taking out forage as part of a rotation, or wanting to establish a more productive forage in that field.
There are three main ways to terminate a forage crop.
- 1. Full mechanical tillage
“This method works good for levelling and drying the seed bed,” Nybo said. It will also help control volunteers. “However, it does require five or six tillage operations.” So, Nybo says, it will take “quite a bit of horsepower, quite a bit of fuel, and lots of manpower.”There are other concerns: intensive tillage can destroy the root channels that the plants have built and dry out the soil. “If you’re in a dryer area like Swift Current, this can be quite an issue,” Nybo said. Salinity can also be a problem. “There’s a lot of soil salinity in the province,” Nybo said — about 11 per cent of Saskatchewan soil. “And it’s not all white land, either.”
- 2. Chemical termination
Forages can be terminated chemically with no soil disturbance. The root channels are left intact, and the moisture is conserved. “There’s a lot of roots that go deep down into the subsurface of the soil,” Nybo said.“Regrowth might be an issue. You might need a second chemical application.” As well, Nybo said, when you’re seeding, “You will need a narrow knife opener.”
- 3. Minimum tillage combination strategy
“Is this the best of both worlds or is it the worst of both worlds?” Nybo asked. In this mixed approach, he said, “we’re replacing one or more tillage operations with a herbicide application.”
Getting the timing right
No matter which method you choose, it’s best done in the summer or the fall before seeding the spring crop.
If you decide to terminate your forage stand in the spring, you’re going to have to go over it many times, in a short time frame. And, it’s going to be tough to break up the lumps to get a smooth seed bed.
If you’re choosing to terminate your forage stand in the spring with a chemical application, Nybo said, “You have to wait until those plants are actively growing before the chemical will be effective.” This will delay seeding. “The spring time termination isn’t really recommended,” Nybo said.
If you terminate your stand in the summer, the best timing will depend on which method you choose. With tillage, “you want to terminate them when the plant energy status is relatively low.” Again, he said, “multiple passes are required.”
If you’re using chemicals to terminate your stand in the summer, you should wait until the plants’ energy is high, and they’re starting to store energy in the roots. You could do this pre-harvest, before your final cut, “and then harvest your crop after the chemical’s got down into the roots,” he said, “or you could do it post-harvest.” This might require a follow-up application for volunteers.
With fall termination, “we’re taking advantage of not losing a year of production.” You’ll be able to take a second cut of your forages without worrying about winter kill, since you’re going to terminate the stand anyway.
If you’re using full tillage, multiple passes are required. “You’ll probably need one or two or three applications in the fall,” Nybo said, “followed by one or two applications in the spring.”
If you’re using chemicals, don’t wait too long. You’ll need to apply the chemicals before the temperature falls below 15 C. If you get a frost, he said, “you’ll want to wait at least three days for that plant to start growing again.” You may need follow-up applications in the spring.
If you’re using a mixed strategy, Nybo suggests a post-harvest application of glyphosate, followed up by tillage, or perhaps multiple tillage applications.
Costs of termination
Nybo cited data from the Saskatchewan Agriculture website. “I think these are kind of minimum costs,” he said. For 2012, the estimated cost of four tillage operations and one harrowing operation was $25.19 per acre. You might require more operations, Nybo said.
For chemical termination, Saskatchewan Agriculture’s estimated cost was $25.29 per acre, based on three applications.
The cost of a mixed strategy was estimated at $31.76 per acre. This included pre-harvest glyphosate, two tillage operations, and a pre-seed glyphosate burnoff.
Costs will be different on each farm. “These will change, with fuel prices changing and chemical prices changing,” Nybo said.