Roots play a pivotal role in crop emergence and seedling health, so the more you can do to protect them from disease, the better chance your crop has to establish well, setting the stage for a successful season.
“You’ve got to have a solid foundation to build your house on,” says Steve Larocque. “If you don’t, it will collapse. It’s the same with plants.”
An independent crop advisor and owner of Beyond Agronomy in Three Hills, Alta., Larocque is the first to say that root health alone won’t ensure a great wheat crop come fall. But it is a very good place to start for the simple reason that healthy roots, generally speaking, lead to healthy plants.
“When you think of what roots actually do, aside from anchoring the plant, they extract water and nutrients from the soil, so any practice that encourages root growth will generate higher yields,” says Larocque.
It really comes down to effective disease management and doing everything you can to protect roots so that they can help get your crop out of the ground as quickly as possible, and continue to help them grow well throughout the season. Here are some tips.
1. Rotate. Rotate. Rotate.
The importance of observing proper rotations cannot be overestimated when it comes to breaking soil-borne disease cycles. All soils contain varying levels of the major disease families, such as fusarium spp., rhizoctonia spp., pythium spp., so managing for them is important to overall root and seedling health.
Economics are driving short rotations where canola is planted every second year on the same field — it’s been the big money maker for years, and shows no signs of stopping. But there are also economic consequences when disease inoculum is allowed to build up in the soil over time. Larocque calls it “super loading.” Not even seed treatments can fully protect roots when disease levels are too high.
The point is that while you might not lose a crop entirely to unchecked soil-borne disease due to poor rotations, plants will struggle to produce well, and that does cost you yield and grade in the end — money, in other words.
2. Test your seed
Seed-borne disease can also have a detrimental effect on root health. If you’re planting your own wheat seed, have it tested to find out what, if anything, you need to manage for.
Don’t forget to ask for a 1,000 kernel weight test as well. Knowing that figure, along with germination and vigour, can help you determine the optimal seeding rate for the seed lot you have.
3. Treat your seed
Seed treatments are a good risk management tool as they can help protect seeds from both insects and diseases. Some seed treatments protect just the seed itself, while others have systemic action and soil mobility, offering protection from to the roots as well as they first emerge. Understand the pest pressures in your field and choose the seed treatment accordingly
4. Consider seeding date
“The push toward earlier seeding, particularly if the soil is cool and wet, increases the risk of disease,” says Larocque. “Seedling mortality might also be higher if it’s cold and wet.” If you see that conditions may be tough, then take steps that will help mitigate them, such as increasing your seeding rate and using a seed treatment with a good fungicide package.
5. Place seed accurately
“Accurate seed and fertilizer placement is equally as important,” says Larocque. “Inconsistent seeding depth can lead to uneven emergence. For example, if 30 per cent of your crop takes three to five days longer to emerge, those plants are already at a yield disadvantage as they compete against bigger, stronger plants beside them.”
6. evaluate all nutrients
Larocque urges growers to consider all nutrients, beyond the usual nitrogen, phosphorus and potassium, that will help root development and function. He says the key nutrients for early season root and seedling development are nitrogen, phosphorous, potassium, magnesium, calcium, zinc and manganese.
“In the case of zinc, there’s a strong correlation between the rate of germination and the level of zinc inside the seed,” he says. That’s because zinc plays a critical role in initiating germination. “Those with high soil pH, high calcium, phosphorus and copper may see a response to seed placed zinc.”
7. Manage risk
As with most cropping practices and decisions, healthy root development is about good risk management and best practices.
“If you’re seeding into cool soils and wet soils, pushing rotations and seeding early, you’re susceptible to disease,” says Larocque. “Understand your risks, test seed and treat.” †