Cover crops comparable to no-till
Climate-change mitigation and adaptation may be additional, important ecosystem services provided by cover crops, said Jason Kaye, professor of soil biogeochemistry in the College of Agricultural Sciences at Penn State. He suggested that the climate-change mitigation potential of cover crops is significant, comparable to other practices, such as no-till.
"Many people have been promoting no-till as a climate-mitigation tool, so finding that cover crops are comparable to no-till means there is another valuable tool in the toolbox for agricultural climate mitigation," he said.
In a recent issue of Agronomy for Sustainable Development, Kaye contends that cover cropping can be an adaptive management tool to maintain yields and minimize nitrogen losses as the climate warms.
Collaborating with Miguel Quemada in the Department of Agriculture Production at the Technical University of Madrid in Spain, Kaye reviewed cover-cropping initiatives in Pennsylvania and central Spain. He said that lessons learned from cover cropping in those contrasting regions show that the strategy has merit in a warming world.
The researchers concluded that cover-crop effects on greenhouse-gas fluxes typically mitigate warming by 100-150 grams of carbon per square meter per year, which is comparable to, and perhaps higher than, mitigation from transitioning to no-till. The key ways that cover crops mitigate climate change from greenhouse-gas fluxes are by increasing soil carbon sequestration and reducing fertilizer use after legume cover crops.
"Perhaps most significant, the surface albedo change (the proportion of energy from sunlight reflecting off of farm fields due to cover cropping) calculated for the first time in our review using case-study sites in central Spain and Pennsylvania, may mitigate 12 to 46 grams of carbon per square meter per year over a 100-year time horizon," Kaye wrote.
"Cover crop management also can enable climate-change adaptation at these case-study sites, especially through reduced vulnerability to erosion from extreme rain events, increased soil-water management options during droughts or periods of soil saturation, and retention of nitrogen mineralized due to warming," he said.
Not a primary management practice
Despite the benefits, Kaye is not necessarily advocating that cover crops be planted primarily for the purposes of climate-change mitigation or adaptation. Instead, he thinks the most important conclusion from his analysis is that there appear to be few compromises between traditional benefits of cover cropping and the benefits for climate change.
"Farmers and policymakers can expect cover cropping simultaneously to benefit soil quality, water quality and climate-change adaptation and mitigation," he wrote.
"Overall, we found very few tradeoffs between cover cropping and climate-change mitigation and adaptation, suggesting that ecosystem services that are traditionally expected from cover cropping can be promoted synergistically with services related to climate change."
According to North Cowichan Mayor Jon Lefebure, when mixed into the lake, the bacterial properties of barley consumes the phosphorus that blue-green algae thrive on. | READ MORE
“Both flax and hemp are widely available in Canada, especially in the West,” said Sam-Brew, a recent PhD graduate from the University of British Columbia’s faculty of forestry. “It’s worth considering their viability as alternative raw materials to wood for particleboard production.”
Particleboards are used in products like countertops, shelves and flat-packed furniture. For her PhD, supervised by professor Gregory Smith, Sam-Brew evaluated the characteristics of flax and hemp residues. She determined their physical and mechanical board properties by soaking and breaking hundreds of particleboards to test their strength and durability.
While Sam-Brew found flax and hemp residues were technically better, she hit one snag. The current economics of manufacturing flax and hemp particleboards in Canada are too high for it to flourish as a competitive material.
“The resin, or glue, needed to produce flax and hemp particleboard is a financial barrier,” she said. Resin holds the particles in the board together and flax and hemp products use expensive resin, called pMDI, as the substitute for cheap urea-formaldehyde.
Sam-Brew was able to show in her PhD research that the amount of resin needed for flax and hemp particleboards could be reduced, which would help lower the cost. Substituting lignin, a plant binder, for a portion of the pMDI resin, could also reduce the cost.
According to Sam-Brew, a burgeoning niche market for flax and hemp particleboards exists in Europe. Decades of flax and hemp processing there and the number of companies in business have led to more competitive pricing.
Sam-Brew said the business case for a similar industry in Canada lies in a facility willing to take a chance on the sustainable alternative considering the growing competition for wood residue. Wood residue is wood waste from sawmills and joinery manufacturers, like wood chips, shavings, sawdust and trims, all highly sought after for use by multiple industries, including biofuel, pellet, pulp and paper.
“They’re all fighting over one resource, which can sometimes be in short supply,” said Sam-Brew. “If a company has to travel long distances to collect the wood waste they need to make their products, that costs them money. The particleboard industry could benefit from using non-wood resources if the price is right.”
For now, flax and hemp particleboard production is at a standstill in Canada. But Sam-Brew remains optimistic.
“Flax and hemp particleboards are lighter than wood,” she said. “The downstream impacts of making a lighter product could mean faster production rates and significant energy and transportation savings.”
“The economics don’t look good now, but they could later.”
Researchers tested the effects of increased CO2 and warmer temperatures on plant water use. Although increased carbon dioxide and warmer temperatures generally improve photosynthesis, in these experiments the researchers found that pores on plant leaves, known as the stomata, were predicted to narrow in these conditions, reducing the amount of moisture plants release into the air.
Although this change may mean some plants are more efficient in their water use in some arid regions, overall this change in plant physiology will have its own climate effects, resulting in less rainfall in some regions, damaging plants and crop yields, says Qianlai Zhuang, professor of earth and atmospheric science at Purdue University.
“This study reveals that while increasing atmospheric carbon dioxide can directly strengthen plant uptake of CO2, it can also reduce plant transpiration, influence global precipitation patterns, and increase warming locally,” he says.
In many terrestrial ecosystems, precipitation is from water recycled to the atmosphere by plants upwind, affecting both precipitation and temperatures, says coauthor Lisa Welp, assistant professor of biogeochemistry in the department of earth, atmospheric, and planetary Sciences.
“The role that terrestrial vegetation plays in rainfall recycling on land is often simplified or overlooked, but it’s a key player in determining regional precipitation patterns and, therefore, productivity in water-limited ecosystems,” Welp says.
“If some plants reduce their transfer of water to the atmosphere by reducing transpiration rates, this results in regional declines in precipitation. It also results in local heating because evaporating water from plant leaves acts like an air conditioner, keeping surface temperatures cooler.”
Overall, the effect is strong enough that there is no net increase in global agricultural production, Zhuang says. In fact, as carbon dioxide increases globally, the modeling showed that plant life in most regions of the world suffers considerably due to rising temperatures and decreased precipitation.
“You cannot look at just one effect in isolation, such as photosynthesis, and make a determination of how it will affect global crop production,” Zhuang says. “There are both direct and indirect effects, and both should be considered.”
Atmospheric carbon dioxide has increased from 280 parts per million before the Industrial Age, which began in the late 1700s, to the current level above 400 parts per million.
Zhuang and graduate student Peng Zhu devised six model experiments using historic climate data from 1850 to 2011. They found that although a few areas would see improved plant growth – including parts of Canada, most of Madagascar, and the southern tip of India – other regions on the planet would suffer.
“This study indicates that the net CO2 fertilization effect will be overestimated unless vegetation-climate feedback effects are taken into account,” Zhu says.
Some scientists say the solution could lie in crops' DNA and are making “gene catalogs” to help farmers grow healthier produce that can withstand climate change. | READ MORE
While drones have a foothold in the game of precision agriculture, some researchers are toying with the idea of using them as pollinators as well.
Researchers ordered a small drone online and souped it up with a strip of fuzz made from a horsehair paintbrush covered in a sticky gel. The device is about the size of a hummingbird, and has four spinning blades to keep it soaring. With enough practice, the scientists were able to maneuver the remote-controlled bot so that only the bristles, and not the bulky body or blades, brushed gently against a flower’s stamen to collect pollen – in this case, a wild lily (Lilium japonicum). To ensure the hairs collect pollen efficiently, the researchers covered them with ionic liquid gel (ILG), a sticky substance with a long-lasting “lift-and-stick-again” adhesive quality – perfect for taking pollen from one flower to the next. What’s more, the ILG mixture has another quality: When light hits it, it blends in with the color of its surroundings, potentially camouflaging the bot from would-be predators. | READ MORE
As a postdoc at the University of Guelph’s College of Biological Science, Liu had been working on a project transforming starch branching enzymes (SBEs) from maize into arabidopsis plants. For weeks, he’d been analyzing the interesting effects of the maize SBEs on the arabidopsis plants’ starch pathways. Then one day he realized the plants he’d been working on had grown much larger than the control plants. Not only that, but there were also far more seedpods, and their leaf and root systems were bigger, too.
“That was the beginning – I saw a really big arabidopsis plant and thought, let’s take a picture. Something has happened biologically,” Liu says.
He showed the photo to his supervisors, Guelph professors Michael Emes and Ian Tetlow.
“We’d found some interesting effects on the starch, and had done all sorts of measurements,” Emes echoes. “And then one day we stood back and looked at the plants, and we finally saw the wood for the trees. We saw these plants were really different.”
A healthy plant from a typical arabidopsis line normally bears about 11,000 seeds; the new plants bore 50,000 seeds per plant – a more than 400-per-cent increase in seed production.
“The plants were bigger, the leaves were bigger, there were more stems, there was more flowering and more seed,” Emes says. “It’s not just that there were a lot more seeds, there was a lot more of everything.
“It was one of those serendipitous events in science. If you’d asked me to produce a plant with more seeds I would have said you couldn’t get there from here,” he adds.
Liu’s focus had been on trying to analyze how the SBEs’ functions changed in arabidopsis leaves, but after this discovery his focus changed to studying the impact on seed yield and biomass, comparing transformed plants with wild-type arabidopsis plants. Importantly, the quality of the oil remained the same as for the non-transgenic plants.
The team published their findings this spring in the Arabidopsis is not a starch crop, but an oilseed genetically similar to canola, so the obvious application of the finding is in breeding higher-yielding oilseed crops for biofuels. Emes and Tetlow have already begun preliminary work with canola, but also foresee potential applications in camelina, soybeans and other crops.
While the dramatic increase in seed production might not occur as easily in canola as in arabidopsis, Liu says even a tenth of the effect would still mean an increase of 40 per cent – a substantial impact on yield.
“This is orders of magnitude different than conventional breeding,” Emes says.
But what, exactly, is going on in the plants?
The good times are here
Emes has a theory that the starch metabolism in the transformants has improved the plants’ ability to grow and reproduce.
The team is working on two lines using two starch genes from maize. In one of the new lines, there is a massive increase of starch in the leaves, which the plant breaks down overnight. In the other line, there is a bigger impact on yield; there is still an increase in starch in the leaves, but it doesn’t all break down at night, leaving a carbohydrate reserve.
“We know that carbohydrates, during seed development, come from the leaf through the vascular system and into the reproductive system. These are important to flower development and what’s called embryo abortion – the plant makes a kind of ‘decision’ on whether or not to produce seeds,” Emes explains. “Flower and seed production is limited by the supply of carbohydrates. So these plants are now saying, ‘The good times are here, let’s go for it.’ ”
Emes suspects that the wild type arabidopsis plant has an endogenous mechanism that constrains growth because it’s genetically evolved to always keep something in reserve. But in the transgenic plants, the brakes have been taken off.
If the scientists can crack the code on the maize SBEs’ effect on oilseeds, Emes sees potential applications for feedstock and oil for human consumption, as well as biofuels. He is currently seeking public and private funding to continue the project in canola.
Liu, now a regulatory scientist for the J.R. Simplot Company, says much more work is required to improve seed quality as well as yield in future breeding projects. “If you want to improve quality, if you want to improve omega-3 fatty acid or other special fatty acid content, for now I don’t have any insight on how you can improve those things, from this study,” he says. “At least, from the analysis of the arabidopsis you don’t see a change in these properties – you just get higher yields.”
But Liu is optimistic about the future applications of his work. “Genes are so powerful,” he says. “One small change could be a potential opportunity for dramatically improving crops.”
Despite efforts to reduce phosphorus levels in freshwater lakes in North America, phosphorus loads to lakes such as Lake Erie are still increasing, resulting in harmful algal blooms. This has led to increased pressure to reduce phosphorus from non-point sources such as agriculture.
While no-till has long been touted for its ability to reduce phosphorus (P) losses in field run-off by minimizing the amount of phosphorus leaving farm fields attached to soil particles, recent research raised concerns that phosphorus levels in tile drainage from no-till fields were higher than from conventionally tilled fields.
A group of long-time no-till farmers, called the ANSWERS group, wanted to see if this was the case on their own farms under their management practices. The farmers approached the government and researchers in order to set up a scientific study.
Funding came from Environment Canada’s Lake Simcoe Clean-Up Fund, the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), the Agricultural Adaptation Council’s Farm Innovation Fund and the Grain Farmers of Ontario. “It was a collaboration between researchers, farmers and government,” says Merrin Macrae, a researcher from the University of Waterloo. Macrae was involved in the project, along with Ivan O’Halloran, University of Guelph (Ridgetown), and Mike English, Wilfrid Laurier University.
The results were good news for farmers who have adopted no-till. There were no significant differences in the P losses between any of the tillage treatments, Macrae says.
The multiple-site, multiple-year project took place from 2011 to 2014 on farm fields near St. Marys and Innisfil under a corn-soybean-wheat rotation. A modified no-till system had been in place at both locations for several years prior to the study. This system is a predominantly no-till system but with some shallow tillage at one point during the three-year crop rotation, for example, following winter wheat. This tillage system is referred to in the study as reduced till (RT); the other two tillage systems in the comparison were strict no-till (NT) and annual disk till (AT) treatments.
Tile water was monitored for three years for each of the tillage treatments. The tile drains were intercepted at the field edge (below ground) to capture edge-of-field losses at each study plot. Discrete water samples were collected from each tile using automated water samplers triggered by tile run-off. The weather was also monitored.
Tillage type did not affect either the dissolved reactive phosphorus (DRP) or total phosphorus (TP) concentrations or loads in tile drainage. Both run-off and phosphorus export were episodic across all plots and most annual losses occurred during a few key events under heavy precipitation and snow melt events during the fall, winter and early spring, Macrae explains. The study shows the importance of crop management practices, especially during the non-growing season, she says.
Both tile drainage flow and phosphorus losses were lower than the researchers expected, Macrae says. Previous studies suggested about 40 per cent of precipitation leaves cropland in tile lines but in this study that proportion was significantly lower.
Macrae admits the researchers were surprised there wasn’t more dissolved phosphorus in the tile drainage water from the NT and RT sites due to the increased presence of macropores and worm holes. However, she points out that these farmers also use best management practices (BMPs) for phosphorus application in addition to using a reduced tillage system. For example, the farmers apply only the amount of phosphorus that the crop will remove. The phosphorus fertilizer is also banded below the surface instead of being surface-applied.
Macrae believes soil type also plays a role in the amount of dissolved phosphorus leaving farm fields in tile lines. “These sites were not on clay soils,” she says. “Clay soils are more prone to cracking, which could lead to higher phosphorus concentrations in tile lines.”
The research highlights the importance of bundling BMPs, Macrae emphasizes. “It’s not just tillage. Farmers should adopt a 4R’s approach: right source, right rate, right time, right place.”
Macrae also says farmers should do what they can to ensure nutrients stay in place, such as maintaining good soil health, using grassed waterways, riparian buffer strips and water and sediment control basins (WASCoBs) where needed, and carefully choosing when and how to apply nutrients.
“Since most of the water movement occurred during the non-growing season, the study showed the importance of how fields are left in winter and why it is important to not spread manure in winter,” she says.
The variability of rainfall intensity, duration and timing will also impact phosphorus losses, she adds.
In future, Macrae hopes to study the impact of tillage on phosphorus losses from clay soils as well as the impact of other management practices such as manure application and cover crops.
“The Canadian Drought Monitor is kind of an early warning system. It provides a clear picture of what is occurring in near real-time. We’re tracking drought conditions continuously so that we know where we’re at and we can respond quicker to problems,” explains Trevor Hadwen, an agroclimate specialist with Agriculture and Agri-Food Canada (AAFC). AAFC leads the Canadian Drought Monitor initiative, working in close collaboration with Environment Canada and Natural Resources Canada.
He notes, “There is a very large process around developing the Drought Monitor maps that is unique to this particular product. It is not as simple as feeding climate data into a computer and having it spit out a map.” That’s because drought is difficult to measure. It can creep up on people as the cumulative effects of ongoing dry conditions gradually mount up. Its effects are often spread over broad areas. And different groups define drought conditions differently, depending on their interests and needs.
So, the Canadian Drought Monitor draws together diverse information like precipitation amounts, water storage levels, and river flow amounts, as well as information about drought impacts on people. And it combines various drought indicators used by the agriculture, forestry and water management sectors into a single composite indicator.
“All that information is put together to create one easy-to-read map product, with just five classes of drought or dryness. Users can get a very clear picture of the areal extent and severity of the drought with one look at the map,” Hadwen says.
The five drought classes are: D0, abnormally dry – an event that occurs once every three to five years; D1, moderate drought – an event that occurs every five to 10 years; D2, severe drought – an event that occurs every 10 to 20 years; D3, extreme drought – an event that occurs every 20 to 25 years; and D4, exceptional drought – an event that occurs every 50 years. The monthly maps are available in an interactive form that allows users to see the changes in drought location, extent and severity over time.
The Canadian Drought Monitor provides useful information for people in many sectors. Hadwen gives some examples: “For agriculture, the information helps with things like where people might want to market grains, where there might be shortages, where there might be areas of good pasture, where livestock reductions might be taking place, all those types of things. The information is also very valuable outside of agriculture, in terms of water supplies, recreational use, forest fires – the list can go on for quite a while.”
The Canadian Drought Monitor maps feed into the North American Drought Monitor maps. “The North American Drought Monitor initiative started about 12 years ago. The U.S. had been doing the U.S. Drought Monitor project for a number of years, and Mexico and Canada were interested in doing similar projects,” Hadwen notes. “So we joined forces to create a Drought Monitor for the continent.” All three countries use the same procedures to monitor, analyze and present drought-related information.
The continent-wide collaboration provides a couple of big benefits. “Number one, drought doesn’t stop at the borders,” he says. The North American initiative provides an integrated view of drought conditions across the continent.
“Also, the Drought Monitor is extremely powerful in terms of the partnerships that have developed and the linkages to some of the best scientists in North America. We share ideas and build off each other, developing better and more accurate ways of assessing drought. We can utilize some of the information generated from U.S. agencies, like NOAA [National Oceanic and Atmospheric Administration] and the National Drought Mitigation Center, and agencies in Mexico. This collaboration effort helps increase the efficiency of the science and the technical aspect of drought monitoring.”
According to Hadwen, the continental collaboration has been really helpful in building Canadian agroclimate monitoring capacity. “Over the last decade or so we have certainly matured a lot, and we’ve started to develop some really interesting tools and applications for Canadian producers and agricultural businesses to help deal with some of the climate threats to the farming industry, including droughts, floods, and everything else,” Hadwen says.
AAFC’s Drought Watch website (agr.gc.ca/drought) provides access to the Canadian Drought Monitor maps and to
other agroclimate tools such as maps showing current and past information on precipitation, temperature and various drought indices, and the Agroclimate Impact Reporter (scroll down to see sidebar).
WHEN COMPLAINING ABOUT THE WEATHER MAKES A DIFFERENCE
If you love to talk about the weather's impacts on your farming operation, the Agroclimate Impact Reporter (AIR) could be for you. If you want your comments about these impacts to make a difference, then AIR is definitely for you. And if you want to find out how the weather is impacting agriculture in your rural municipality, your province, or anywhere in Canada, then AIR is also for you.
AIR is a cool online tool developed by AAFC that grew out of a previous program to collect information on some drought impacts. "We have had a program in place to monitor forage production and farm water supplies in the Prairies for well over 15 years. Then about three years ago, we started to develop a tool to replace that program – a tool that would be national in scope and that could gather information on a whole range of agroclimate impacts," Hadwen explains.
AIR taps into a volunteer network of producers, AAFC staff, agribusiness people and others. "We use crowd-source data for this, gathering information from a whole wide variety of people. Some of them we know through our registered network, and others have a subscription to our email box and provide comments to us on a monthly basis," he says.
"We're trying to gather as much information from as many people as possible on how weather is impacting their farming operations. We ask the participants to do a short [anonymous] monthly survey, usually about 25 quick multiple choice questions, to let us know how things are going."
AIR is collecting impact information in several categories including: drought, excess moisture, heat stress, frost, and severe weather (like tornadoes and hail storms).
"We plot that information and produce a whole bunch of individual maps showing very subject-specific information from each survey question," Hadwen notes. "We also have a searchable online geographic database. On a map of Canada, you can zoom in on different regions and see where we're getting reports of a large number of impacts or not as many impacts. You can even drill down into that map and see the exact comments that we are getting from [the different types of respondents, in each rural municipality]."
The information collected through AIR provides important additional insights into the weather conditions and related issues and risks. He says, "Sometimes the data we have in Canada isn't as fulsome as we would like, and sometimes it doesn't tell the whole story. For instance, the data [from weather stations in a particular area] might show that it didn't rain for a very long period and the area is in a very bad drought, but the producers in the area are telling us that they got some timely rains through that dry period that helped their crops continue to grow. Or, the data might show that we received a lot of rain in a season – like we did in 2015, if you look at the overall trend – but the farmers are telling us that there were big problems in the spring. So, combining both those types of information certainly helps draw the whole story together a little better."
AIR information feeds into the Canadian Drought Monitor to help in assessing the severity of drought conditions. As well, the AAFC's Agroclimate group incorporates AIR information into its regular updates to AAFC's Minister and senior policy people; it helps them to better understand what is happening on the land, and that knowledge can help in developing policies and targeting programs.
Information from AIR is also valuable for businesses that work with producers, such as railroad companies wondering about regional crop yields and where to place their rail cars, and agricultural input companies wondering if they need to bring in extra feed or fertilizer.
AAFC is in the process building AIR into a national program. "We want to collect agroclimate impact information from right across the country. We have a history in the Prairie region, so we have more Prairie producers providing information. We've made inroads into B.C., so we're getting some reports from there already," Hadwen says. "[Now] we're going out to Atlantic Canada and Ontario. And over the next couple of years, we'll be expanding AIR right across the country."
If you are interested in becoming a volunteer AIR reporter, visit www.agr.gc.ca/air.
May 12, 2016 - With farming season soon to be underway, a research group is looking for canola to help with their study.
Prairie Agricultural Machinery Institute (PAMI) researchers are hoping to further pursue a study they began in 2014 by monitoring canola used for summer storage.
Apr. 26, 2016 - Honey bee colonies in the United States are in decline, due in part to the ill effects of voracious mites, fungal gut parasites and a wide variety of debilitating viruses. Researchers from the University of Maryland (UMD) and the U.S. Department of Agriculture recently completed the first comprehensive, multi-year study of honey bee parasites and disease as part of the National Honey Bee Disease Survey. The findings reveal some alarming patterns, but provide at least a few pieces of good news as well.
The results, published online in the journal Apidologie on April 20, 2016, provide an important five-year baseline against which to track future trends. Key findings show that the varroa mite, a major honey bee pest, is far more abundant than previous estimates indicated and is closely linked to several damaging viruses. Also, the results show that the previously rare Chronic Bee Paralysis Virus has skyrocketed in prevalence since it was first detected by the survey in 2010.
The good news, however, is that three potentially damaging exotic species have not yet been introduced into the United States: the parasitic tropilaelaps mite, the Asian honey bee Apis cerana and slow bee paralysis virus.
"Poor honey bee health has gained a lot of attention from scientists and the media alike in recent years. However, our study is the first systematic survey to establish disease baselines, so that we can track changes in disease prevalence over time," said Kirsten Traynor, a postdoctoral researcher in entomology at UMD and lead author on the study. "It highlights some troubling trends and indicates that parasites strongly influence viral prevalence."
The results, based on a survey of beekeepers and samples from bee colonies in 41 states and two territories (Puerto Rico and Guam), span five seasons from 2009 through 2014. The study looked at two major parasites that affect honey bees: the varroa mite and nosema, a fungal parasite that disrupts a bee's digestive system. The study found clear annual trends in the prevalence of both parasites, with varroa infestations peaking in late summer or early fall and nosema peaking in late winter.
The study also found notable differences in the prevalence of varroa and nosema between migratory and stationary beehives. Migratory beekeepers -- those who truck their hives across the country every summer to pollinate a variety of crops -- reported lower levels of varroa compared with stationary beekeepers, whose hives stay put year-round. However, the reverse was true for nosema, with a lower relative incidence of nosema infection reported by stationary beekeepers.
Additionally, more than 50 per cent of all beekeeping operations sampled had high levels of varroa infestation at the beginning of winter -- a crucial time when colonies are producing long-lived winter bees that must survive on stored pollen and honey.
"Our biggest surprise was the high level of varroa, especially in fall, and in well-managed colonies cared for by beekeepers who have taken steps to control the mites," said study co-author Dennis vanEngelsdorp, an assistant professor of entomology at UMD. "We knew that varroa was a problem, but it seems to be an even bigger problem than we first thought. Moreover, varroa's ability to spread viruses presents a more dire situation than we suspected."
For years, evidence has pointed to varroa mites as a culprit in the spread of viruses, vanEngelsdorp noted. Until now, however, much of this evidence came from lab-based studies. The current study provides crucial field-based validation of the link between varroa and viruses.
"We know that varroa acts as a vector for viruses. The mites are basically dirty hypodermic needles," Traynor said. "The main diet for the mites is blood from the developing bee larva. When the bee emerges, the mites move on to the nearest larval cell, bringing viruses with them. Varroa can also spread viruses between colonies. When a bee feeds on a flower, mites can jump from one bee to another and infect a whole new colony."
Nosema, the fungal gut parasite, appears to have a more nuanced relationship with honey bee viruses. Nosema infection strongly correlates to the prevalence of Lake Sinai Virus 2, first identified in 2013, and also raises the risk for Israeli Acute Paralysis Virus. However, the researchers found an inverse relationship between nosema and Deformed Wing Virus.
Some viruses do not appear to be associated with varroa or nosema at all. One example is Chronic Bee Paralysis Virus, which causes loss of motor control and can kill individual bees within days. This virus was first detected by the survey in the U.S. in 2010. At that time, less than one per cent of all samples submitted for study tested positive for the virus. Since then, the virus' prevalence roughly doubled every year, reaching 16 per cent in 2014.
"Prior to this national survey, we lacked the epidemiological baselines of disease prevalence in honey bees. Similar information has been available for years for the cattle, pork and chicken industries," Traynor said. "I think people who get into beekeeping need to know that it requires maintenance. You wouldn't get a dog and not take it to the vet, for example. People need to know what is going on with the livestock they're managing."
While parasites and disease are huge factors in declining honey bee health, there are other contributors as well. Pesticides, for example, have been implicated in the decline of bee colonies across the country.
"Our next step is to provide a similar baseline assessment for the effects of pesticides," vanEngelsdorp said. "We have multiple years of data and as soon as we've finished the analyses, we'll be ready to tell that part of the story as well."
Frequent fallow without nitrogen fertilizer led to long-term soil degradation and lower yield. Photo by Bruce Barker.
In this era of focusing on short-term results, a long-term viewpoint is indeed, unique. But the long-term crop rotation study established in 1951 at Lethbridge, Alta. is a model for the long view, especially in biological systems where changes can take decades.
“We still maintain the long-term plots. We need to reapply for funding every three to five years for these studies, to purchase seed, fertilizer and pesticides,” Elwin Smith says. Smith is a bioeconomist at Agriculture and Agri-Food Canada (AAFC) at Lethbridge Research Centre.
Smith, along with colleagues Henry Janzen and Francis Larney, established a six-year bioassay study in 1995 that was imposed on the long-term Lethbridge plots to look at the impact of long-term rotations on soil quality, productivity, nitrogen (N) fertilizer effects on wheat yield and quality, and whether N fertilizer can overcome poor long-term rotations. The results were analyzed and published in the Canadian Journal of Plant Science in 2015.
The long-term plots
The soil was an Orthic Dark Brown Chernozem clay loam with level and uniform topography, and calcareous subsoil. Seven rotations were established, reflecting crop rotations that were common in 1951. In 1985, several changes to the plots and rotations were made to add alternate crops being grown at the time and an additional N management component to maintain crop productivity. Thirteen rotations were included in the study from 1985 through 1994 (see Table 1 below).
From 1995 to 2000, all 116 plots were no-till seeded to spring wheat cultivar Katepwa. A preseed burnoff of glyphosate was applied to control weeds. In-crop weeds were controlled with appropriate herbicides. Phosphorus (P) fertilizer was applied with the seed to all plots as 0-45-0, at an average rate of 7.9 kg P/ha (16 lb P2O5/ac).
The rotation plots for each replicate were divided into two randomly assigned strips, one with zero N fertilizer (control) and one strip with N fertilizer applied at an average rate of 56 kg N/ha (49 lb N/ac).
The first two years of yield data were excluded from the bioassay analysis of total wheat yield because of confounding short-term effects of land use the year prior to the study.
Smith says the 1995 soil analysis indicated crop rotations with less frequent fallow and with N input had higher soil quality, as indicated by soil organic carbon (SOC) and light fraction carbon (LF-C) and N (LF-N). Organic matter was higher in long-term plots that had N added to the system or with lower fallow frequency. The higher organic matter also contributed to improved wheat yield. (See Fig. 1 below.)
“The presence of frequent fallow in crop rotations had a negative effect on total wheat yield, long-term productivity and grain N concentration, even with past and current application of N fertilizer,” Smith reports.
Treatments fertilized with N had a four-year total wheat yield approximately 30 per cent higher than unfertilized treatments. Without the application of N, total wheat yield was highest in the FWWHHH rotation, followed by plots that previously had native grass, and continuous wheat with previously added N. Smith says plots without N and high fallow frequency (FW, FWW) resulted in lower total yield regardless of N added in his study.
In Smith’s study, N fertilizer was unable to compensate for the lower productivity of fallow-based rotations that did not replenish N removed by the crop, or for rotations that were in fallow one-half of the time and had added N.
“The yield differences from this study demonstrated that previous N fertility management and crop rotation impacted current crop yield. Management practices that replenished N to the system had higher current yield, while rotations with fallow reduced current yield. The current application of N fertilizer could not overcome the yield disadvantage from previous systems with frequent fallow and no N fertilizer,” Smith says. “Producers need to recognize the importance of crop rotation and N fertility management on both long-term and current crop productivity.”
Glenlea Research Station at the University of Manitoba is home to several long-term systems-level research studies. Photo by Julienne Isaacs.
According to Don Flaten, a professor in the department of soil science at the University of Manitoba (U of M), when new research data from one of U of M’s long-term studies is published, word quickly spreads to his colleagues around the world. “Before long, they’re calling to say, ‘Don, why didn’t you tell us about this data sooner?’” he says.
Data from long-term research studies becomes exponentially valuable over time, but such studies are becoming rarer – particularly when they operate at the systems level, analyzing a variety of qualities in the agricultural system, and their interactions, over time.
“Studies like these are always under pressure because they consume resources,” says Martin Entz, a professor in the U of M’s plant sciences department, and head of Glenlea Research Station’s 24-year long-term organic and conventional cropping study. “When times get tough, they’re on the chopping block.”
Flaten says universities are especially challenged to maintain long-term trials. He leads the National Centre for Livestock and the Environment’s (NCLE’s) long-term manure and crop management field laboratory at Glenlea. “Our study has no permanent technical support,” he says. “It relies on year-to-year funding from granting agencies. Agriculture and Agri-Food Canada’s (AAFC) support for long-term studies is vital.”
The project also relies on local industry partnerships with the Manitoba Pork Council and the Dairy Farmers of Manitoba, and a variety of national and provincial grants.
Glenlea is home to several long-term systems-level research studies, including Entz’ study, which began in 1992, and is Canada’s oldest evaluation of organic cropping systems. But Entz says there are even older studies across Canada, such as AAFC’s long-term crop rotation study based at Indian Head Research Farm, which has been running since 1958. Lethbridge is also home to a very simple rotation study (not systems-based) that has been running since 1911.
“These studies are national treasures, producing amazing results that we’d never expect,” Entz says.
According to Christine Rawluk, NCLE’s research development coordinator, long-term systems-level research studies are important because systems are incredibly complex and change over time. “If you make a decision based on a short-term study, you don’t know if the change you’re implementing has true benefits or negative consequences in the long-term,” she says. “Time is a really important part of the system itself.”
Systems are vulnerable to a wide range of factors, such as weather and soil variability, and management practices.
NCLE’s manure and crop management study analyzes the effects of different types of manure fertilizer on soil nutrients over time. “One year or even three years doesn’t give you the whole picture, particularly with nitrogen, because the yields don’t start showing an effect from solid manures before five years or more,” Rawluk says. “So if we were to look at it for just one growing season, we wouldn’t have an accurate sense of how organic reserves of soil nitrogen are becoming available over repeated years.”
Flaten says farmers take a long-term approach to farming by applying specific management practices over extended periods, so it only makes sense to analyze practices in the long-term at the research level. These studies can account for the impact of short-term practices in the long term. “And sometimes there are results you don’t understand, which challenges us to realize there’s more to systems than we know,” he says.
Entz says his long-term study has paid off in spades. “One of the things we’ve discovered is that the more ecological farming systems that use fewer external inputs over time, with small adjustments to management, have become very productive and economically and biologically efficient. We’d never have discovered that if we’d only done that for five years,” he says.
The Glenlea studies have a highly practical element. Researchers actively encourage involvement from industry groups and producers so they can influence the studies from the ground up.
NCLE’s studies aim to encourage partnerships between crop and livestock producers. “We’re looking for opportunities to capitalize on the integration of livestock and cropland,” Rawluk says. “Whether it’s a mixed operation or a situation where your neighbour has annual crops where you’re applying your manure, we’re looking for opportunities for collaboration at the farm level.”
There’s another key benefit to Glenlea’s long-term systems-level research studies: they actively encourage interdisciplinary conversations and cross-departmental collaboration, which counteracts a culture of specialization that has actually been counterproductive to agricultural research.
Long-term systems-level studies are designed to be sustainable, which means seeking input from experts across the university. “When considering parameters for the Glenlea study, we consulted with economists, soil scientists, entomologists,” Entz says.
“Specialization has become the norm, and agriculture is no different – we have specialists in particular areas of soil fertility, and in plant diseases,” he notes. “You’d be surprised how difficult it is for those specialists to talk to each other. But the farm system is not specialized – what happens in one part affects the other parts. That specialization has precipitated very specialized research. Everyone is solving a problem their own way. But at some point you have to put it all together.”
Flaten calls long-term systems-level studies “goldmines” of data for agricultural research. Entz agrees. “The systems-level approach to long-term studies is valuable because life works at the systems level,” he says.
The 2015 drought in Alberta and Saskatchewan is part of a thousand-year history of recurring Prairie droughts. That history includes multi-year and even multi-decade droughts. If you overlay that difficult past with a warmer and possibly drier future, what might that mean for Prairie agriculture?
“Looking at the zone on the Prairies where most of the field crops are grown, the 2015 winter-spring is by far the driest in the past 68 years,” David Phillips, senior climatologist with Environment Canada, says. For the Prairie region, good quality weather records only go back 68 years, although records for the major Prairie cities start in the late 1800s. “Although parts of Manitoba had more precipitation than normal in 2015, parts of western Saskatchewan and Alberta were exceedingly bone dry.”
The severe drought conditions persisted in much of Alberta and Saskatchewan until late July, when rains came to parts of the drought-affected region, especially in Saskatchewan. Phillips gives an example: “In Saskatoon, from Jan. 1 to July 30 in 2015, the total precipitation, snow and rain, was 147 millimetres (mm). Looking at records that go back to the 1880s, the driest weather for January to July was in 2001, with 124.6 mm. But in 2015, during the first 26 days of July, there was only 18 mm of rain in Saskatoon, and then from July 27 to 31, there was 67 mm. So, from Jan. 1 to July 26, Saskatoon had a grand total of only 80 mm. Even in 2001, for that same period from Jan. 1 to July 26, the total was 112 mm, so it wasn’t even close to as dry as it was in 2015.”
Trevor Hadwen, agroclimate specialist with Agriculture and Agri-Food Canada, highlights some of the agricultural impacts of the 2015 drought in Alberta and Saskatchewan. “Early on, people were having to reseed crops because of poor emergence. Then it was just too dry for crops to emerge from the soil. So a lot of crops were later seeded, and by the time they got moisture, they were very late into the season and people were concerned that frost would be an issue in the fall.
“Another impact starting very early in the spring was that pasture and forage production was very poor. Very dry and delayed productivity of grasslands developed throughout Saskatchewan and Alberta, and there was a lot of concern for feed availability.”
Hadwen says the late July rains saved the crops in Saskatchewan and parts of Alberta, but other areas in Alberta continued to suffer drought conditions. “By the end of the summer, Saskatchewan was above average for rainfall despite the extremely dry spring. In Alberta, the drought areas really started to concentrate around the Edmonton region, and in some portions of the south. In southern Alberta, rainfall shortages were made up by some irrigation in the spring, helping those areas very significantly. So the main areas of impact for drought overall this summer ended up being in the Edmonton and northern Alberta regions.” By the end of October, significant drought conditions still persisted in central and northern Alberta.
Phillips notes the 2015 growing conditions could have been even worse. “The summer of 2015 was about the tenth warmest, but thank goodness it wasn’t any warmer than that because there would clearly have been more drought issues. The other thing that saved some growers, particularly in Saskatchewan, was that 2014 had been very wet, so the crops [in the spring of 2015] were probably sucking off that moisture from 2014.”
Past trends, future possibilities
Prairie droughts are definitely not a new phenomenon – just ask Dave Sauchyn from the University of Regina. He has been studying past climate trends on the Prairies by measuring the widths of annual growth rings in trees.
“We’ve been collecting dead wood for 25 years now; we have more than 8000 pieces. In order to grow, trees need light, heat, soil and water, and they have plenty of all of those in summertime except water. So, the pattern of tree growth tells us very much about the amount of water available every year for the last thousand years,” Sauchyn explains.
“We’ve found droughts that were much more severe and much more prolonged than anything we’ve seen on the Prairies in the last 120 years, including the 1930s. For example, just before Europeans came to the Canadian Prairies, there were droughts of 10 or 20 years in duration.”
Sauchyn’s research shows that, over the past 1000 years, the Prairie climate has included many droughts that have lasted a decade or longer.
He adds, “Based on the science, it is entirely possible that we could see prolonged drought some time in this century.”
In the coming decades, the Prairies are likely to continue getting warmer. “The most consistent scenarios show increasing temperatures, so a continuation of the trend observed over the last half century. And much of the warming is occurring in the winter, so the Prairies and most of Canada are getting less cold. Minimum temperatures – the temperatures at night and in winter – are rising,” Sauchyn explains.
Predictions relating to Prairie moisture conditions are more complex. “One trend is more precipitation, especially in winter, because as the temperature of the air increases, it can hold more moisture. Also, the source of our moisture is the oceans, and the oceans are getting warmer, so they are producing more water vapour,” Sauchyn says. Warmer, wetter weather sounds promising for Prairie crop production. However, the models also indicate the extra water may not necessarily arrive in ways that are best for crop production. Some of the extra water may arrive as winter rains, when crops aren’t growing, and the range of moisture conditions will likely be much larger, swinging between extremely wet and extremely dry conditions.
So the predictions present a mix of advantages and disadvantages for Prairie crop production, including opportunities to grow higher value crops that require a longer growing season, increased risks of drought stress, heat stress and waterlogging, and changes in disease, insect and weed issues as these organisms adapt to their changing environment.
“I think it is a matter of adapting, doing things differently, storing precipitation, using creative ways to do more with the precipitation you get, and trying to adapt your planting decisions to cushion the blow,” Phillips says. “By preparing for the changing weather and responding to it, we can mitigate the effects of it or capitalize on it. I think we have to be climate smart, weather smart, in what we do – try new things and be resilient enough to change according to how things are going.”
Overall, Phillips is optimistic about the future for Canadian crop production in the face of climate change. “There are many challenges today for growers, but incredible advances have been made. And I think better science will help deal with some of the challenges ahead. Also, I think we’re in better shape in Canada than in many other countries to be able to weather the storm, so to speak, of a warming climate. I think growers are willing to try new things, and with a changing climate, that will be one of our strengths. The inventiveness, adaptability and resiliency of growers make me think the future is bright.”
Sauchyn has been studying adaptation and vulnerability to drought on the Prairies in recent years. He says, “Adaptation is nothing new to Prairie farmers. The Prairies have one of the more inhospitable climates in the world – throughout the history of Prairie agriculture, farmers have had to adapt to a climate that is colder and drier and has a much shorter growing season. They just have to keep adapting because the climate keeps changing like a moving target.”
ARE THE PRAIRIES GETTING STORMIER?
Although news and social media stories may give the impression that Prairie weather is getting stormier, the jury is still out on the actual trends. That’s mainly because Prairie records aren’t long enough to establish firm trends.
John Hanesiak, a University of Manitoba scientist who studies storms and atmospheric processes, explains that at least 30 years of good records are needed to start examining weather trends and the records for Prairie storms are just getting to that length.
“For tornadoes, our record is really good from about 1985 onwards. For heavy rains, hail, damaging windstorms and things like that, our record is not quite as good because people generally don’t report those events as well. A storm event could be quite local and Environment Canada may not necessarily know how bad it was. Also, sometimes there isn’t the ability for someone to go and verify that the storm event was severe.”
Another complication is that reporting biases can muddy the trends. “There is ‘population bias’: you get better reporting from areas with a lot of people than from places where there aren’t many people. [So as the population grows in a region, you get more reports.] And people are more prone to report these events nowadays than they used to be – people have cameras all the time, whereas even 10 years ago that wasn’t the case,” Hanesiak notes. He adds there are statistical methods to try to account for those biases, “but we don’t really know how good they are.”
Hanesiak summarizes the current situation for Prairie storm events: “For tornadoes, usually we see between 40 and 45 per year on the Prairies, based on a 30-year average; Manitoba gets about 10, and Alberta and Saskatchewan get about 15 or 20 each per year. There are usually about 30 strong wind events and about 15 heavy rain events per year. And there are about 60 hail events per year; most of those are in Alberta because of the proximity to the mountains.”
Some of Hanesiak’s research involves figuring out future trends in severe storm events. “One of the problems that has been plaguing us for the last while is that climate models are usually needed to do long-range projections and the climate models have spatial scales in the order of 120 to 200 kilometres. But we need to get down to 10 kilometres or less to resolve the detail that is needed for convective summer storms.”
Fortunately, regional climate models have recently been developed that have scales down to about 30 or 40 kilometres. So they can capture more details of the jet stream patterns and moisture patterns in the atmosphere than the climate models can. Hanesiak says, “We know that more moisture and stronger winds in the upper parts of the atmosphere are important for producing severe weather. So we can look at those kinds of things and see how they have changed, and try to tease out what we might expect in the future.”
Hanesiak’s research group is currently using this approach to run a hail model. The researchers are just starting to analyze the data from this work, but their initial findings are intriguing. “It looks like we might expect to see fewer hail days in the future on the Prairies, but when they do happen they will tend to have more larger hail, so they’ll have more damage potential,” Hanesiak says.
“Also, there seems to be a seasonal shift. At present, [in the southern Prairies] we tend to see most of our hail and severe weather around the June-July time period. But that seems to be potentially shifting by mid-century toward the April-May time period, with less hail in July-August. The northern Prairies and the Northwest Territories don’t see that many hail events now, but in the future it looks like their June-July-August period will be quite changed, with more frequent and more severe hail events.”
Hanesiak’s research group is planning to do more of this type of research. For instance, next year, one of Hanesiak’s graduate students will be using the same approach to look into future trends in Prairie tornado events.
Researchers used polyethylene tanks meant for fish, at Simpson, Sask. Note the grass growth on top and the drip line. Photo by Larry Braul, AAFC.
Thank the Swedes for this idea: “biobeds” that promise to protect water quality for generations to come. The concept represents a low cost, environmentally friendly way to deal with the rinse water flushed out of agricultural field sprayers.
According to Larry Braul, Agriculture and Agri-Food Canada water quality engineer in Regina, the biobed is an organic filter for pesticides, using conventional low value material. The use of biobeds has become an accepted practice in Europe in the past 15 years.
Braul and Claudia Sheedy, research scientist with AAFC at Lethbridge, Alta., are co-leading the project to develop a biobed model to support Canadian farmers. Starting with one biobed at Outlook, Sask. in 2014, AAFC expanded the project in 2015 to sites at Simpson, Sask., and Grande Prairie and Vegreville, Alta. An additional biobed was constructed in fall of 2015 and will be monitored in 2016 at Lethbridge. “At the end of 2016, we expect to have enough data to produce a construction, operation and maintenance manual for biobeds,” Braul notes.
Initial results promising
“The first year at Outlook, it was highly effective. It removed more than 98 per cent and up to 100 per cent of the pesticides it received. That was very positive, and the results we just got back for 2015 are very similar,” Braul says.
“Our climate is much colder than Europe and we have more intense rainfall events. We are working to address those issues with designs revised for the Prairies,” he adds.
In principle, a biobed is relatively inexpensive, easy to use and significantly accelerates the natural breakdown processes for pesticides. The most challenging aspect at this point is in finding or developing an inexpensive method to easily collect the sprayer rinse water. On most farms when rinsing, the sprayer arms are fully extended while water is pumped through the system. As a result, a catch basin for that spray would need to be up to 120 feet long by about 20 feet wide and would need to drain the spray to a point where it can be collected.
The contained biobed for the rinse water uses a mixture of topsoil, compost and straw. It provides an ideal habitat for microbes to break down the pesticides carried in the rinse water, to the point they pose no threat to the environment.
In the project’s first year, Braul and Sheedy discovered the biobed at Outlook was still frozen a few inches below the surface in May, when they hoped to use it. It needed to be warmed to about 10 C, so that microbes could process the rinse water.
They resolved that issue for 2015. Braul says, “Microorganisms like warm conditions. In a new biobed, we put heat tape at the bottom. We can get them up to almost 30 C at the end of May, so they can really start breaking down the pesticides. With a little heat application at the right time, we are probably doubling the decomposition rate they’re getting in Europe.”
European research found that half and up to 90 per cent of pesticide contamination in groundwater could be traced to the places where sprayers were rinsed, Braul says. Two factors go into that: there’s a concentration of pesticides in one place, and a lot of water washing it down. It’s too much for the microorganisms to process.
Often the topsoil is stripped off and replaced with gravel at the site where the farm sprayer is rinsed. This removes the organic matter that absorbs pesticides and allows the pesticide to leach through the soil zone. Often, it’s fairly close to the well that supplies the water.
“That’s the worst situation for managing the site,” Braul says. “It becomes quite a significant source of contamination. Instead, if we capture that rinsate, contain it and treat it, we can make a significant impact on the contamination problem.”
The Swedes were first to address the problem. They collected rinsate and applied it to the top of a simple hole in the ground filled with the biomix material. “The Swedes applied the rinsate to the top of the biomix and let it seep through into the ground. It was the standard for six or seven years. It was a heck of a lot better than putting it on gravel, because it absorbed a lot of the pesticide. Now, with more sensitive instruments, we know that model doesn’t remove all the pesticides,” Braul says.
Current practice is to build a contained biobed up to a metre deep. In the UK, that would be lined at the bottom with clay or plastic, and drained with weeping tile.
For their first project, Braul and Sheedy built a wood frame structure. On later projects they also used open polyethylene tanks meant for fish. Plans call for putting the biomix into big tote bags already used for storing granular fertilizer or pesticide. “Really, you can use anything as a container for the biomix,” Braul says.
The biomix material needs three basic components: topsoil (from a field is best, because it will already have microbes adapted to degrading pesticides); woodchips or straw (to provide the lignin for microbial food and structure); and, compost or peat (to provide the organic matter that absorbs the pesticides).
Among design variations tried in 2015, the most efficient was a two-cell system about a half-metre deep. Each cell has a six-inch layer of crushed rock at the bottom. A sump pump collects leachate from below the crushed rock in the first cell and pumps it to the surface of the second cell. “Two cells remove a much higher percentage of the pesticide than single cell biobeds,” Braul notes.
Although literature from the European experience suggests that nearly all the microbial activity happens in the top six inches of the biobed, most beds are one metre thick to provide additional absorption capacity. At the University of Regina, microbiologist Chris Yost is using DNA testing to determine the type and number of microbes at various depths. Yost hopes to determine the region of greatest microbial activity.
At Outlook, a two-cell biobed only a half-metre deep worked better than expected, Braul says. In practice, degradation of pesticides in the biomix can take three to six months, he adds.
There’s still a need to deal with the reasonably clean leachate coming from the bottom of the biomix, and a need for eventual disposal of the biomix itself. “Effluent has an extremely low level of remaining pesticide. We recommend spraying it on an area that has some organic matter and lots of microorganisms, and allow nature to do its work. One option is to put it into a tank and spray it someplace, or you can sprinkle it safely on grass or drip it along a row of trees. The little amount of remaining pesticide will be degraded in the topsoil,” he says.
Setting up a collection pad for the sprayer rinsate would be the biggest single cost. It can be constructed from heavy plastic but a concrete pad is ideal. “If you want to collect everything you rinse out, you have a fairly large concrete pad. Depending on where you are, it probably could cost $5,000 to $10,000. That’s a big challenge – but some inexpensive creative options are possible,” Braul says.
Mar. 21, 2016 - Alberta Agriculture and Forestry (AF) undertakes a number of research projects to ensure the quality and safety of land, air, and water for our food producers. Although long-term monitoring shows the overall quality of Alberta's irrigation water is good or excellent, a study is currently underway to use DNA fingerprinting techniques to determine the sources of contamination of irrigation water. While there are no current concerns, this is an opportunity to improve water quality for the future.
The Water Quality Section of AF is currently working with the Taber Irrigation District on a pilot study to understand the sources of E. coli in irrigation water. The study is funded by Growing Forward 2, a federal-provincial-territorial initiative. The District has made water quality a key part of their mandate to ensure farmers are growing the best quality crops.
Often, irrigators are required to have water quality tests completed to market their produce, and with recent changes in regulations in the United States (US), this need may increase. In the US, the Food Safety Modernization Act requires testing of water that is used to irrigate fruits and vegetables which are consumed raw. These regulations may affect Alberta producers with irrigated crops destined for export to the US.
This study will assist in identifying opportunities to continue to improve water quality, and help producers meet their food safety requirements for the global marketplace. The key item being measured in the study is E. coli. Generic E. coli are present in the intestines of most people and animals, and are excreted in feces. E. coli are therefore used to measure fecal contamination in water. The testing is complicated, as there are "naturalized" E. coli that occur in the environment and are not indicative of fecal contamination.
"Research gives us a better understanding on the amount of fecal and naturalized E. coli in irrigation water. The discovery of naturalized E. coli is very important because food safety is concerned about fecal contamination. If we find E. coli in water, we need to determine whether it is fecal or naturalized, which then determines if there is a food safety concern or not," says Andrea Kalischuk, director of water quality, AF.
"Our study in the Milk River area showed cliff swallows and cattle contaminated some of the water, but a significant proportion of naturalized E. coli was also observed" says Kalischuk. Whatever the study identifies as a source of contamination, the research team and irrigation district will need to work with producers to seek a balanced solution that supports both the agriculture industry and wildlife habitat, while meeting food safety requirements.
This is the final year of a three-year study, and a summary report will be shared with producers on AF's website in the fall of 2017.
Wheat beside canola stubble. Photo by Steve Larocque.
Morrin, Alberta farmer and certified crop advisor Steve Larocque’s journey into extreme precision agriculture was made possible by a dose of chance, an eye for potential, and a willingness to step into the unknown, followed by a whole lot of brain-bendingly intense mental energy. The results, preliminary yields suggest, may change the way top farmers use controlled traffic farming (CTF).
“We chanced on what I call fencerow farming almost by accident, which I guess is the way most really cool, innovative things are discovered,” Larocque says. “Now that we’re seven years in, I really believe it is the future of controlled traffic farming for top farmers, at least for those who are as anal or type A as me.”
Back when Larocque first jumped into CTF, his initial challenge was to figure out how to adjust his equipment to manage residue while staying on CTF tramlines. While most people seed right between previous rows, Larocque found that ground hard and dry, especially in low moisture years. Instead, he offset his hitch by just two inches, allowing his shanks to seed right alongside the previous year’s stubble where the soil is comparatively softer and moister. While this seed placement is unusual, Larocque’s wouldn’t be much of a story if his efforts had ended there. But, about the same time, he started thinking more and more about something that at first glance seems entirely unrelated: old fence lines.
Over decades, fence lines catch drifting soil, building up a four, five, even 10 foot wide raised area that boasts a substantially deeper A horizon (top soil strata) compared to the rest of the field. Long after the fence line is removed, the built up area offers a better growing medium with richer, more deeply placed nutrients and a greater amount of beneficial biological activity.
Like many farmers, Larocque noticed time and again that his yield monitor spiked as his combine heaved up and over the headlands of long-gone fence lines. There had to be a way, he figured, of mimicking that fence line effect along every row of his field to achieve a yield jump in each and every plant. Not one to watch and wait for others to innovate, Larocque converted his farm into a large-scale “fencerow farming” experiment.
Since he was already placing seeds close to old stubble to capture maximum moisture, Larocque began seeding in a four year placement rotation (ie: row A in year 1, two inches left of row A in year 2, two inches right of row A in year 3, back on top of row A in year 4). This seed placement resulted in a six inch wide “fencerow” every 12 inches throughout the field.
Intensive soil testing suggests Larocque’s fencerow seeding method is generating a host of benefits. The consistent location of the stubble row builds up and concentrates organic matter like mini fencerows. In dry years, the highest soil moisture content is found inside the previous year’s root ball and can spell the difference between weak and strong emergence. Equally importantly, Larocque says, fencerow farming allows him to improve the availability of nutrients through row loading.
“If you seed across your stubble or even between rows, you dilute your mobile nutrients. You’ll accumulate them over time but never in high concentration. What we are trying to do is create a biological zone that is super loaded with as much nutrient as possible – macros, micros, biologicals, even fungicides and pesticides – anything that can support the plant in furrow,” Larocque says. “We keep all of the nutrients within the same furrows, maximizing availability to the crop, decreasing nutrient immobilization, and super loading the biosphere to support tons of biological activity.”
“We’ve been using fertilizer in the same way for 40 years. We’re seeing yield improvements because we have better varieties than we used to, but we’re not seeing yield improvements from how we actually use fertilizer. There are ways of using the same inputs we’ve always used but using them with much more efficiency,” he adds.
With six seasons of fencerow farming under his belt, Larocque says it is still too early to prove with yield data the single most important question about fencerow farming: whether it actually produces sufficient financial benefit to justify the required RTK technology’s $35,000 price tag, and the admittedly intense mental effort.
“We believe that it absolutely will prove itself, but we haven’t put in enough years yet. And we still have some fine-tuning to do to tighten up our furrows so we only cover 25 per cent of our land with furrows, not 50 per cent as we do now. All indications show that we’re on the right track. But it takes at least six years to change things substantially enough in the soil’s structure, biological health and nutrient availability to be really noticeable, and we’re only on year seven,” he says.
While Larocque’s preliminary results look good, the results of long-time fencerow farmer Dean Glenney offer even more promise. Glenney has been quietly growing corn in southern Ontario according to fencerow farming principles for more than 20 years. Larocque hopes to soon achieve comparable results to his fencerow farming predecessor.
“Glenney is pulling 300 bu/ac corn while everyone else around is pulling 170 bu/ac corn on the same rainfall. That gets a guy like me excited,” Larocque says. “It may take a decade to see the results but once we’re there, we hope to achieve what Dean Glenney has in Ontario with the same technique.”
Larocque is convinced today’s generally accepted concept of controlled traffic farming just barely scratches the surface of precision agriculture’s benefits. While he admits his precision-to-a-whole-new-level farming technique might sound extreme, he firmly believes the results from his farm will pave the way for top farmers.
“There’s no question: what I call fencerow farming is the future for the top 10 or maybe 20 per cent of Alberta farmers,” Larocque says.
In fact, the greatest deterrent to greater uptake is not the technology itself but rather the culture and expectations surrounding Canadian farming, he says.
“Until the pain of staying the same is more than the pain of change, people will continue to do the same thing over and over, and watch from the sidelines. Why would you change when things are working OK – not working amazingly, but working OK?” Larocque says. “You see much greater adoption of innovation in places like Australia or South America because they don’t have back stops like crop insurance there. Guys have to be really sharp or they get knocked out of the business.”
Fencerow farming does take an added level of management, admits Larocque. For him, though, the mental exercise required to create, analyze, fine tune and problem solve a workable fencerow farming system into existence in his fields makes farming “a lot more fun.”
To farmers who might be nervous about jumping into this intense form of farming, he says: “Half the battle is just getting your head wrapped around it. You absolutely can do it, and you can do it on larger scale. You don’t flip the switch and start fencerow farming, you just baby-step into it. Once you put in the up-front time to get started, controlled traffic farming makes your life easier because you know exactly where to go. And if you can get bigger returns for the same amount of crop inputs? That’s what we need to prove to get people on board.”
Dense, compacted subsoil layers can have serious crop yield impacts. They can impair root penetration, limiting root access to water and nutrients, and they can decrease water infiltration and increase the risk of ponding, runoff and erosion. One way to try to improve soil with a compacted layer is to use a deep tillage implement, but that can be expensive. So University of Saskatchewan (U of S) soil scientist Jeff Schoenau is leading a new project to evaluate precision subsoiling.
A common cause of subsoil compaction is repeated wheel traffic, for example in travel and loading areas, especially if heavy field equipment is used on clayey soils in wet conditions. As well, natural soil-forming processes can create a hardpan layer, such as in Solonetzic soils.
Solonetzic soils have a hard, sodium-rich B horizon (the soil layer below the topsoil, or A horizon). “The presence of large amounts of sodium causes some soil dispersion and the creation of these hardpans due to clay movement into the B horizon,” Schoenau explains.
The majority of Canada’s six to eight million hectares of Solonetzic soils are found in Alberta and Saskatchewan. Solonetzic soils tend to occur in areas with high-sodium parent materials or where groundwater carries sodium into the soil. For example, there are broad areas dominated by Solonetzic soils along the edge of the Missouri Coteau in Saskatchewan, such as the Central Butte area and the Radville to Estevan area.
Building on previous findings
Although subsoiling was studied in past decades on the Prairies, not much research had been done recently until Schoenau’s research group conducted a study that began in 2010. In that study, they used a paraplow, a type of subsoiler that has been on the market for quite a while. As the tip of a paraplow moves through the subsoil, it lifts and then drops the soil column, loosening the soil. It causes limited disturbance of the soil surface, as the loosening point is run at a depth of 45 centimetres.
That study’s treatments compared spring and fall subsoiling, two different subsoiling depths and two different shank spacings. It took place at three irrigated sites and one dryland site in south-central Saskatchewan in the Lake Diefenbaker area.
One site had soil structural issues because of its Solonetzic soils. Unfortunately, the study’s fieldwork took place during two unusually wet years, 2010 and 2011, and the Solonetzic site had to be abandoned due to flooding.
At the other sites, the researchers didn’t detect any serious compaction problems. Nevertheless, subsoiling did affect soil conditions and water infiltration at those sites.
“One of the things we found is that subsoiling did significantly increase the infiltration of water and reduced the density and strength of the soil. How long those effects persist depends on the moisture conditions; we tended to see less persistence if it was really wet than if it was dry,” Schoenau says.
Subsoiling resulted in variable and typically small yield increases of about five to eight per cent. He notes, “If you compare that yield advantage to the subsoiling costs, it was about a breakeven proposition. We concluded that the effects would have to persist longer than one year or else be of a larger magnitude in order for subsoiling to be really economical on these particular soils, where serious compaction issues were not evident.”
So, if you break even on subsoiling costs in soils without serious compaction problems, then might subsoiling be economical if it were just targeted at those patches in a field where serious soil structural problems occur?
Schoenau’s new precision subsoiling project could help answer that question.
He is working on this project with his colleague in the department of soil science, soil physicist Bing Si. The Saskatchewan Agriculture Development Fund, Saskatchewan Wheat Development Commission and Western Grains Research Foundation are funding the project.
The two sites for this project are both in the Lake Diefenbaker area near Central Butte and are both dryland locations. At one site, the researchers have induced some soil compaction through repeated wheel traffic. At the other site, they have set up a smaller experiment on a field with significant structural limitations due to a Solonetzic hardpan layer.
In the fall of 2015 at the two sites, the researchers began by mapping the location and depth of spots where the subsoil’s soil strength and density were high enough to limit root growth. “We have a cone penetrometer, and we use a sampling grid to make maps of the penetration resistance [soil strength] before and after the subsoiling,” explains Schoenau. A cone penetrometer is an instrument consisting of a narrow steel shaft with a cone at one end. As the penetrometer is pushed into the soil, the pressure gauge at the top end of the shaft indicates how much pressure is needed to move the cone through the soil.
Also in the fall, the researchers carried out the subsoiling in replicated plots, comparing three treatments: subsoiling only those parts of the plot identified as having a dense subsoil layer; subsoiling the entire plot; and no subsoiling, as a check.
They used a modern subsoiling implement – a John Deere 2100 minimum till ripper provided by Western Sales, a Saskatchewan farm equipment dealer. These types of subsoilers have a set of coulter disks to open the soil and then a following set of shanks with a near-horizontal tip (or share) at the base of each shank. Schoenau says, “As the unit moves through the soil there is little disturbance at the soil surface, just from the shank itself. But down deep at the depth of operation, which is around 30 centimetres, the shank creates a lifting or loosening action.”
He explains that dense subsoil layers typically occur at variable depths below the surface. He adds, “In some of our early work, we found that if we went too shallow, subsoiling didn’t work as well. Similarly if we widened the spacings above what was recommended and went to really wide spacings, we didn’t get as good results.”
For the next two years, the researchers will be monitoring the effects of the 2015 subsoiling on soil properties and crop yields. Schoenau says, “In the spring of 2016, we will be looking at the persistence of the effects on bulk density and penetration resistance. Then we’ll measure crop yield at the different transect points in our replicated plots. And we’ll be doing that for the following two years so we will have yield data from wheat in 2016 and canola in 2017.” Then they’ll evaluate the costs and benefits of precision subsoiling compared to subsoiling of a whole field.
For crop growers with fields that have zones of high-density subsoils, the project should provide new information on the value of precision subsoiling.
“I think it will show the potential benefits of applying the subsoiling technique to soils and particularly to areas of a field where there is an issue with soil compaction from wheel traffic under very wet conditions or naturally occurring dense B horizons,” Schoenau says.
“I think it will give us insight into how subsoiling affects the properties of the soil and ultimately how that translates into any potential yield benefits and enhanced economic returns to the grower.”
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