By Mitchell Japp, M.Sc., PAg, Provincial Specialist, Cereal Crops
Agriculture continually evolves and changes. Equipment changes have been remarkable over the past century, moving from horses and other animal power to tractors and even the beginnings of autonomous machines. Or, think about the introduction of synthetic fertilizers and pesticides – products available in abundance today that contribute to healthy, safe, and abundant food supply, but weren’t available in even the relatively recent past. These innovations are marvels of efficiency, but is agriculture resilient?
Resiliency is the ability to bounce back or recover from difficulties. What difficulties are expected on a modern farm? Drought, diseases, insects, weeds, and loss of productivity are among the many risks and difficulties managed in agriculture. As a society we rely on agriculture to be able to overcome and bounce back when these difficulties arise. Is that reliance a reasonable expectation? The productivity and efficiency of modern agriculture offers more than just efficiency.
On the prairies, drought is expected. The images of the vast clouds of dust in the 1930s are still impactful, even for those of us who never experienced the Dirty Thirties. Fast forward 50 years to the late 1980s. The drought then was comparably dry relative to the 1930s, but without the vast clouds of dust. There was still wind erosion then, but less than in the 1930s. Just 15 years later when the next drought happened, zero or minimum tillage was practiced on most farms in Saskatchewan and continuous cropping was widespread. The stubble left standing in the fields under conservation tillage practices anchored the soil and prevented wind from getting that dry topsoil into the air and moving it around. Not only did the standing stubble help retain productive topsoil, it helped in moisture retention by preventing further drying from winds and heat, as well as capturing snow. Farmers had found that conservation tillage (zero or minimum till) was effective for many reasons, including being economical to them. It also made their farming operations more resilient.
Conservation tillage contributes to resiliency in more than just managing erosion. It makes nutrient cycling more efficient and helps farmers be more efficient in their use of fertilizers. Those fertilizers contribute to resiliency. Early farm settlers benefitted from the high fertility of the prairie soils, but that fertility was being lost over time as the nutrients were exported in grain or lost to the environment. The ability to add nutrients to replace what was being taken away gave producers the ability to produce more grain and keep their soils productive in the long-term. Productive soils are more resilient.
Optimizing fertility has been matched well with improved genetics. Crop breeding has increased the yield potential of crops on the prairies. Improved agronomy has helped to achieve that yield potential. In addition to increasing yields, breeding also works to preserve yields. Breeding introduced resistance to pests and has built widespread resiliency. Some of the diseases of the past were overcome by introducing resistance to rusts that were devastating to earlier varieties. Now, breeders have been introducing improved resistance to fusarium head blight and resistance to wheat midge.
Breeding is an important component in improving yields, protecting crops from pests, and improving resiliency, but higher-yielding crops with optimum fertility can be an ideal environment for some diseases and insects to grow. Weeds can also take advantage of open space and available nutrients. Pesticides and integrated pest management (IPM) practices aid in preserving the yield potential of a crop. Pesticide products add resiliency to modern agriculture because of the role they play in managing pests that can reduce yield and/or crop quality. IPM integrates different management practices that help control pests.
Crop rotation is a common tool that is used to manage pests. For example, if a weed is difficult to control in one crop, such as wild oats in oats, the weed will be managed in years when oats is not grown so that there are fewer wild oats to grow when oats are grown. Also, seeding rate and timing can be managed to help the crop outcompete the wild oats, further advantaging the crop. When many tools are used to manage pests, it’s less likely that the pest will be able to adapt successfully against all of the management tools.
But when too much reliance is placed on a specific tool, such as a pesticide or genetic resistance, there is a risk of losing those tools, which can decrease the overall resiliency of the agricultural system. IPM requires a thorough understanding of the pest in order to create conditions that no longer favour that pest, reducing the reliance on pesticides exclusively as a management tool. Reducing reliance on pesticides increases the resilience of pesticides as a component of IPM.
Herbicide resistant (HR) weeds have been increasing, at least in part, due to over-reliance on herbicides, and now there are populations of some weedy species that are resistant to multiple herbicide groups. If these HR weeds continue to be managed with the same approach, they will eventually be resistant to all effective herbicides. As a result, crop rotation options may decrease, limiting producers’ ability to use good crop rotations as a management tool, or producers may revert to other practices such as tillage. Both outcomes reduce resiliency of the agricultural system.
Fortunately, there are options. Managing for herbicide resistance can include herbicide layering, which is the practice of using multiple effective modes-of-action (Groups) over the growing season, as well as more than one effective mode-of-action per application, since the chance of finding a weed that is resistant to a single mode-of-action is orders of magnitude greater than for two herbicides working together. Other technological solutions can help, as well. Harvest Weed Seed Control, in production in Australia, attaches a machine to the combine to either destroy weed seeds as they pass out of the combine or to windrow them for later management, thereby preventing weed seeds from returning back to the majority or all of the field. Moving further to the future, machines are being designed to be able to distinguish individual weed plants from a crop and deliver control in the form of either non-selective herbicide or, eventually, laser and high-pressure water jets.
These technologies are at their very early stages of development for field crop systems like those on the prairies, but the continued development, uptake, and application of new technologies will continue to maintain and enhance the resiliency of agricultural systems.