Alberta and Prairie-wide survey assesses weed populations

Summer 2017 marks the first general weed survey of Alberta since 2010, providing scientists, agronomists and farmers with a current picture of what’s out there.

If you made a list of the most prevalent and potentially yield-damaging weeds on your farm last year, what would they be?

For many growers, the lineup of weeds to be controlled has changed over the past 10 years. Weed management practices and available crop protection products have evolved accordingly.

The purpose of the 2017 Alberta Weed Survey is to obtain solid data on the abundance and distribution of weed species in the province’s pulse, cereal and oilseed crops. Julia Leeson, Weed Monitoring Biologist with Agriculture and Agri-Food Canada, is running the project, which spans the three Prairie provinces. Alberta Pulse Growers is one of the organizations that has contributed funding for the survey’s Alberta component.

“It’s been seven years since the last Alberta general weed survey,” Leeson said, “and 10 years since the last survey of herbicide-resistant weeds in Alberta. The survey allows us to see what’s changing and what’s increasing, which allows us to be better able to manage weeds.”

Coming to a farm near you

Leeson is leading a team of more than 40 people working on the survey in the summer of 2017. Their job is to survey fields and compile weed profiles from 1,200 farms across the Prairies.

The team randomly selects quarter-sections in the three provinces and contacts landowners for permission to visit. Weed surveyors will be walking fields after the producers have completed their normal in-crop weed control.

“We just walk through the land, wearing booties so it really is minimal impact,” Leeson said. “Most people are very positive about letting us on the land. We want to look at what’s been missed by the in-crop application, and what will be going to seed that could become a problem next year. We will also collect seed to be tested to determine the extent of herbicide resistance in various weed species.”

The 2017 Alberta Weed Survey is a massive undertaking. Compiling and interpreting the data will take roughly two years. Leeson expects to publish her findings in early 2019. Which newer weeds are on the march? Which long-time foes are declining? How is the incidence of herbicide-resistant weeds shifting?

The survey data will tell the tale, but Leeson’s in no doubt: when it comes to weed management in crop production, the times are changing.

“The weed spectrum has changed significantly over the past 20 years,” Leeson said. “For many years, the Top 20 weeds were fairly consistent. Changes in tillage practices and herbicide use patterns and crop rotations have shaken things up. That’s why it’s so important that we do this survey.”

Ongoing rotational study considers long-term pulse benefits

With a valuable 24-year crop rotation study about to end, a new project leader took up the challenge, with pulse producer funding to keep it going and head in new directions.

Back in the early 1990s, dryland crop rotations in southern Alberta were neither diverse nor especially productive in terms of soil health and growers’ returns per acre. The wheat-fallow crop rotation was still king.

Look today. Producers now have more options for growing different crops, protecting the soil and making a good living doing it. The big change: less fallow, more pulses.

“Soil health, as an issue, is very hot now,” said Eric Bremer, Head of R&D at Western Ag Innovations. “We often talk about the benefits of pulses, but it’s another thing to quantify the benefits in terms of bushels per acre or a financial benefit.”

In 2015, Bremer saw an opportunity to do this through a provincial government crop rotation study at Bow Island, which had been active for 24 years. The project had been managed for many years by Alberta Agriculture and Forestry’s Ross McKenzie, then by Doon Pauly when McKenzie retired. Pulses, mainly peas, had been in the rotation for many years.

Beginning in 2016, with funding support from Alberta Pulse Growers and others, Bremer proposed to keep the site going and take the study in new directions.

A valuable resource

Everyone knows that a pulse crop this year sets up a nice cereal crop next year. With the Bow Island site and its precious 24 years of data as his starting point, Bremer wanted to look deeper.

“I wanted to know the long-term benefits of growing pulses,” he said. “We know that it’s a benefit the year after, but now we’re looking two or three years ahead.”

Bremer’s methodology is to plant the same crop on the whole site each year. In 2016, it was hard red spring wheat, with or without 72 lb. of nitrogen per acre. For 2017, he’s putting in mustard. Pulses, likely peas, will be part of the rotation in the longer term.

Bremer will assess the impact of these cropping practices on yield, soil organic matter and soil health more broadly, as well as associated economic implications.

Over time, Bremer expects to build a solid set of data on the agronomic and economic benefits of having pulses in a brown-soil-zone crop rotation.

Which pulses, and how often, produce the best result in terms of productivity, soil health and dollars in farmers’ pockets? The coming years will fill out the picture. One thing’s for sure, though: Given the known but not yet fully quantified benefits of pulse crops, the once-standard wheat-fallow rotation won’t be making a comeback any time soon.

“Twenty years ago, there was still a lot of fallow-wheat, but it has gradually decreased because of zero-till, better agronomy and better knowledge,” Bremer said. “Pulse crops in Alberta have made a dramatic difference to cropping practices, giving producers more options, more valuable crops, and reducing the need for fertilizer.”

Sub-activity 1: Selection for dry bean canning quality

Acceptance of dry bean cultivars is dependent on both dry seed (seed size, shape, colour, colour retention and seed coat integrity) and processed seed (canning quality) traits. Percentage hard-to-cook seed, hydration coefficient after soaking and blanching, washed drain weight, texture, colour, clumping and appearance of seeds after canning are important traits to processors and consumers. A greater understanding of the above factors will enable: i) breeders to select genotypes with improved canning quality traits in a breeding program; ii) growers to choose cultivars with optimum quality for commercial production in their respective growing environments; and iii) processors to refine the canning protocol depending on the cultivar.

Sub-activity 2: Early maturing lines with improved disease resistance

Dry bean cultivars of six (pinto, Great Northern, yellow, black, red and pink) bean market classes are grown in rotation with cereal, oilseed, potato, sugar beet and forage crops primarily under irrigation. The days to maturity of dry bean cultivars range from 100 to 105 days in Alberta which has a short growing season on the prairies. A major impediment to dry bean production is the lack of early maturing dry bean cultivars with adequate level of resistance to the most prevalent diseases including white mould and common bacterial blight. Development of disease resistant cultivars is one of the most effective and environmentally sustainable methods for reducing yield losses and promoting stable crop production.

Sub-activity 3: Micro-climate management for white mould disease control

Sclerotia of S. sclerotiorum can only produce apothecia in the top 4 cm of the soil. Factors affecting sclerotia germination under lab conditions have been extrapolated to understand sclerotial germination behaviour as it relates to microclimate variables, disease development and yield potential under field conditions. Based on these studies, allowing the top 4 cm of the soil to dry should negatively affect ascospore production and subsequent initiation of disease onset. However, the effect of microclimate and fluctuating wet and dry periods on ascospore release and white mould development have rarely been investigated under field conditions. The proposed research would aim to determine whether microclimate management, provided by changes in irrigation scheduling and dry bean canopy architecture, could decrease the rate of ascospore release during the susceptible flowering period, without negatively affecting bean yield. As a result, disease management of white mould of dry bean will be enhanced by de-synchronizing time of spore release with crop susceptible period through modification of plant architecture and irrigation.

Sub-activity 4: Improved nutritional values of dry bean to promote its utilization in health foods

The nutritional value of dry bean has not been fully explored and utilized. Dry bean produced in Canada is primarily exported as a raw commodity. Although dry bean has been identified as a health food with low glycemic index (GI) for decades, the information on its resistant starch and dietary fibres is limited. This Activity will conduct a comprehensive study to evaluate contents and variations of resistant starch and dietary fibre in dry bean germplasm and cultivars, identify APG Research Investment: Production Projects 25 Summer 2015 novel dry bean lines with high levels of resistant starch and dietary fibres, and further improve nutritional value of dry bean by promoting its utilizations in health foods. This study will be the first to systematically investigate and characterize resistant starch and dietary fibres in dry bean germplasm and cultivars of diverse market classes. The results of the proposed study will enhance commercial value of dry bean produced in Canada and create new processing opportunities for use in health food.