Which cover crop is best?
By Carolyn King
With dozens of different cover crops to consider, deciding which ones to grow can be a challenge. Now an online tool is available for crop growers in Eastern Canada to help make that choice much easier.
“In recent years, there has been a lot of talk about cover crops. But for the most part, people generalize, saying ‘cover crops can do this, cover crops can do that,’ which is true in general terms. However, growers work with specifics – they grow specific cover crops and have specific goals,” says Dr. Laura Van Eerd at the University of Guelph’s Ridgetown Campus.
“To match the cover crop with your goals, you have to pick the right cover crop. By using this decision tool, you can see which cover crops will perform the best and eliminate the ones that aren’t good choices for your goal.”
Van Eerd led the effort to develop the Cover Crop Decision Tool for Eastern Canada. She was already familiar with this type of tool because she had worked with the Midwest Cover Crop Council (MCCC) on its Cover Crop Decision Tool for seven U.S. Midwest states and Ontario. So the Pesticide Risk Reduction Program at Agriculture and Agri-Food Canada approached her to lead the project to adapt the MCCC tool for Eastern Canada. The project fits with pesticide risk reduction objectives because certain cover crop species can help in managing disease, weed and/or insect infestations in crop production systems, along with providing other sustainable agriculture benefits.
“We had a team in each province that decided which cover crops and which criteria were suitable for their province,” explains Van Eerd. The provincial specialists included: Anne Verhallen (Ont.), Stephanie Sanchez (Que.), Claude Berthélémé (N.B.), Viliam Zvalo (N.S.) and Shauna Mellish (P.E.I.).
Like Van Eerd, Verhallen was involved in the development of the MCCC tool. “Ontario is a member of the Midwest Cover Crop Council, so we had done some of the tool development work already for Ontario. This new project was an opportunity to expand the tool to the rest of Eastern Canada and to make it a little more vegetable-focused because the Midwest Cover Crop Council tool is more field crop-focused,” says Verhallen, soil management specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) in Ridgetown.
She adds, “It was also an opportunity to make a truly Canadian version of the tool. We had brought in farmers to look at what we were doing with the Midwest Cover Crop Council version and we got some feedback from them. We incorporated that into this new tool. So it’s similar to the MCCC tool, but there are some very significant differences in how the information is presented in some of the visuals.”
The five provincial teams compiled information from published scientific papers, research studies, on-farm experience and practical knowledge. They developed information for each cover crop species, including its potential benefits and disadvantages, agronomic characteristics and management practices for the province. The planting dates for each cover crop are based on expert analysis of 30-year regional weather data and are specific to each county in each province.
Van Eerd says, “The tool is based on expert knowledge from many people, including growers, people from seed companies, soil and crop experts, extension personnel and researchers. They have gone through the data and validated it based on their knowledge, and made certain that it is specific for each province.”
Verhallen was involved in developing the Ontario portion of the tool. “For me, bringing together a group of farmers and industry people was probably the most fun but also the most challenging part – trying to get everyone in the same room, or at least on the phone, at the same time. We needed to do that because – although as many as possible of the cover crop ratings in the tool are based on research and data – a lot of them are based on experience: farmer experience, industry experience and extension experience across the province. And everybody has a different perspective on things, and what we see down here [in the Ridgetown area] is a lot different than you’ll see in eastern Ontario. We had to take all those comments into consideration. So it was great fun to work on it and to come to a consensus on the ratings and what comments we were going to make on the benefits, warnings and so on.”
Overall, more than 50 experts were involved in developing and validating the Cover Crop Decision Tool for Eastern Canada.
Interactive, easy to use The new interactive tool is available at http://decision-tool.incovercrops.ca/. Available in both English and French, the tool provides quick and easy access to accurate, relevant information to help crop growers make informed decisions on cover crops, and to increase adoption of this practice in Eastern Canada.
The tool allows the user to specify the province and county, and to select the main crop that the cover crop is aiming to benefit. All five provinces have main crop options for vegetable cropping systems; Ontario also has main crop options for field cropping systems.
The user can select among several other options to describe the field’s growing conditions, such as its drainage and flooding characteristics, and can choose up to three goals for the cover crop (see Table 1, previous page).
The tool’s graphic display is easy to understand and updates immediately as the user enters each new choice. The graphic display rates the cover crop options – about 30 in total – for how well each one meets the selected criteria, highlighting those that best meet the criteria. And it shows the recommended planting window for each cover crop.
Clicking on the name of a specific cover crop in the main display links the user to an information sheet about that cover crop, including such details as the cover crop’s life cycle and growth habit, agronomic practices, advantages and challenges.
So the tool allows growers to efficiently identify and compare cover crop options suited to their local conditions and their goals. “The tool gives a lot of information really quickly and allows growers to choose what they want from the cover crop,” notes Van Eerd.
“It’s kind of a one-stop-shop deal where you can look at a variety of different cover crops and their attributes, including characteristics that will be really good and things that might be a problem. All that information is in one place,” says Verhallen. The tool also allows growers to try out various scenarios to see how different cover crops would fit in with their production system.
The Cover Crop Decision Tool for Eastern Canada can be continuously improved in the years ahead. “The tool has been designed so we can easily update it if new cover crops come onto the scene or if new recommendations come out,” says Van Eerd. “The long-term goal is to perhaps pull the teams together in a few years and have a re-look at the data to make sure it is still relevant.”
Verhallen adds, “I think it is a good tool and it will get even better with time. We know a lot more about some of these cover crops now than we did two or three years ago. So about every three years or so we’ll probably review and update the tool.”
The Pesticide Risk Reduction Program funded the project to develop the tool. Matching funds from an Agri-Food and Rural Link’s Knowledge Translation and Transfer grant supported development of
the Ontario field crop portion of the tool.