Top Crop Manager

Top Crop Manager
A profitable increase

A profitable increase

Too many variables often make it difficult to recreate the same effective strategy year after year in agriculture.

Crop nutrition problems can become pest problems

Crop nutrition problems can become pest problems

Deficiency of a single nutrient can impair healthy plant growth.

Variable-rate planting

Variable-rate planting

As corn hybrids are being developed to respond better to higher seed populations, interest is growing in variable-rate seeding.

Field management to reduce blackleg risk

Field management to reduce blackleg risk

For many years, blackleg disease on the Prairies was managed fairly successfully through the use of disease resistant varieties and an extended rotation.

Cold temperatures hamper soybean nodulation

Cold temperatures hamper soybean nodulation

The 2014 growing season was the worst year in recent memory for poor root nodulation and nitrogen (N) fixation in soybeans.

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Agronomy

A new study aims to help ensure that Prairie oat growers and processors can continue to produce safe, healthy products. Preventing problem fungi from becoming problems

A new project will be filling some information gaps on problem fungi so Prairie oat growers and processors can continue to produce safe, healthy products. The project is targeting Fusarium and Penicillium fungi. Under certain conditions, these fungi can infect cereal grains and other products and may produce toxins, referred to as “mycotoxins.” And those mycotoxins can cause food and feed-safety issues. The Canadian Grain Commission’s Dr. Sheryl Tittlemier, who is the lead researcher for the project, explains that Fusarium infections start in the field. Warm, moist conditions during flowering favour development of Fusarium head blight (FHB). Along with the potential for producing mycotoxins, FHB reduces grain yield, grade and quality. Several species of Fusarium can cause FHB in cereals. According to Tittlemier, the two major species of concern for oats on the Prairies are Fusarium poae and Fusarium graminearum; as well, Fusarium avenaceum is found occasionally. Fusarium poae produces various mycotoxins, such as nivalenol. Fusarium graminearum’s  mycotoxins include deoxynivalenol (DON), the most common mycotoxin associated with FHB. Fusarium avenaceum produces several mycotoxins, which are just beginning to be studied by scientists. In Canada, Penicillium verrucosum is the fungal species of concern in the production of a mycotoxin called ochratoxin A (OTA). Infection by this fungus and production of OTA occur during grain storage if temperature and moisture levels are too high. Affected kernels cannot be detected by the human eye or optical scanners. According to Tittlemier, it is not yet clear whether Fusarium and Penicillium fungi might be less or more of a concern in oats than in other cereals. And it’s also not clear whether the occurrence of these fungi on the Prairies might be increasing or decreasing over time. “We see variations from year to year, which is not surprising because there are a lot of factors involved in the infection and mycotoxin production. But when we look at our long-term monitoring data, it’s really hard to discern whether there is an overall trend,” notes Tittlemier, who is a research scientist and the program manager for trace organic and trace element analysis at the Grain Research Laboratory of the Canadian Grain Commission (CGC). She thinks the reason these fungi are becoming more of a concern could be because of the increased regulatory activities regarding their mycotoxins. “Health Canada in recent years has proposed guidelines for ochratoxin A in cereals including oats. And internationally, with the Codex Alimentarius [a collection of international food standards, guidelines and codes of practice], there is discussion about establishing new tolerances for DON in various cereals. So I think this is bringing these two mycotoxins into people’s minds.” The importance of this issue to the whole oat industry is shown by the diverse participants in the project. Tittlemier says, “The project is bringing together the Prairie Oat Growers Association with their support, the support of the Saskatchewan Ministry of Agriculture, the elevators and the mills that are providing us with samples, and the Canadian Grain Commission. And within the CGC, there’s my research group, the microbiology research group, and the milling research group, and inspectors are helping us with obtaining samples and the logistics of the samples. I think it’s going to benefit the project that we have all these players coming in from different aspects of the oat industry.” The Prairie Oat Growers Association (POGA) is administering the three-year project, as well as co-funding the project with the Saskatchewan Ministry of Agriculture’s Agriculture Development Fund. “This project is an important step in ensuring that Canadian oat producers can continue to provide safe and healthy products that are trusted around the world,” says Shelanne Wiles Longley, POGA’s interim executive director. “We’re starting to see increasingly rigorous testing of oats and oat products, especially in Europe. So it’s really important, more so now than ever, to be proactive in this area,” notes Longley. “For example there is a proposed trade agreement between the European Union and Canada, and that market is likely going to require testing for mycotoxins in oats and other products.” She adds, “If ever a problem arose with mycotoxins, it could drastically limit the export market and the uses of oats, which could then have drastic effects on oat producers.” Studying fungal occurrence and fate“This project is going to fill some knowledge gaps, giving us a better handle on what is the current situation about where we find the fungi, where we find the mycotoxins, and what happens to them when we process the oats,” says Tittlemier. The project has two main parts. One part involves disease surveillance, to see if there are any patterns in where and when the fungi and their mycotoxins occur. The other part will examine processing effects on the fungi and their mycotoxins. To carry out the first part, the researchers will receive oat samples from elevators across the Prairies in the summers of 2014, 2015 and 2016. In addition, they’ll be getting weekly samples over the three years from elevators that consistently handle oats throughout the year and from a mill that takes deliveries throughout the year. The researchers will analyze these samples to see if there are differences from region to region, from summer to summer, and/or from week to week within the year. “Knowing the [disease occurrence] situation and providing that information to oat growers and grain handlers can help them to be proactive to prevent problems. For instance, if certain regions have more disease pressure, then they may have to take extra management steps, perhaps through agronomic practices, or maybe the grain elevators need to be more aware of proper testing to make sure they’re not running into issues with high levels of mycotoxins in deliveries,” explains Tittlemier. For the other part of the project, the researchers will assess the effects on the levels of the fungi and their mycotoxins of sample processing methods for testing and of commercial processing techniques. “We’ll work with the milling group at the Grain Research Laboratory and look at how processing of oats – whether it is for sample preparation or commercial processing with dehulling, steaming, kilning and so on – might affect the fungi and mycotoxins in the various product streams,” says Tittlemier. The researchers are already working on sample testing procedures. She notes, “In our labs we’re using validated testing methods, so we’re confident with the tools we have. But there are challenges with oats. For example, oats have a higher fat content than other cereal grains, so a test that you use for wheat may not work for oats in the same way.” Another testing challenge, especially for Penicillium and ochratoxin A, is how to obtain representative samples. That’s because the contamination tends to occur in only a small pocket within the grain mass. Tittlemier explains, “You need to ensure the sample that you’re testing in the lab is representative of the bin or the truckload or the railcar or what have you. So you have to do the sampling properly to make sure you’re not missing that little pocket of contamination.” Processes like dehulling, steaming, kilning and milling could affect the presence of the fungi and their mycotoxins, depending on where on the seed the problem occurs. Tittlemier says, “We know for wheat that some mycotoxins occur on the outer seed coatings. And from some preliminary tests we know that if you dehull oats, the mycotoxin concentrations can be greatly reduced. However, some other mycotoxins with different chemistries might actually make their way into the kernel.” Information from this part of the project could help testing facilities ensure accurate, precise results. It could also help oat processors to have a better understanding of the effects of different processing methods. And it could help food safety regulators, too. Tittlemier explains, “Whether it’s Health Canada or international groups, when they go to set maximum limits or guidelines for oats, they can take into account these steps that could reduce exposures, so they can set relevant limits.”   

Machinery

A 120-foot boom equipped with six Greenseeker sensors moves through a wheat field. The system senses the colour and biomass of the crop and sends a signal to a rate controller to adjust product rates up or down.  Searching for solutions

Ontario crop researchers are putting the Greenseeker technology under the microscope to see if it can work for the wheat crop. They’re testing its ability to analyze the nitrogen (N) needs of the crop, which would help farmers apply the right amount of fertilizer. Peter Johnson, provincial cereal specialist with the Ontario Ministry of Agriculture and Food and Ministry of Rural Affairs, along with Dr. David Hooker of the University of Guelph, Ridgetown Campus, is leading trials to adapt the system to Ontario’s conditions. Johnson’s goal is to increase profits for farmers by applying higher N rates to areas where the crop will respond while reducing the rates where there’s a lower response. “At the end of the day, we’re trying to figure out how to have better-targeted nitrogen applications, more yield where possible, less environmental impact where the yield doesn’t have that potential, and more dollars in the grower’s pocket,” says Johnson. The Greenseeker system from Trimble Agriculture uses optical sensors with an integrated application system to measure crop status and variably apply the crop’s nitrogen requirements. The technology works in real time, allowing the operators to make variable rate app-lications on the go. The sensor uses light-emitting diodes to generate red and near-infrared (NIR) light. The light is reflected off of the crop and measured by a photodiode at the front of the sensor head. Red light is absorbed by plant chlorophyll and healthy plants absorb more red light and reflect larger amounts of NIR than those that are unhealthy. The reflectance values are used to calculate the Normalized  Difference Vegetation Index (NDVI), which is an indirect measurement of the crop’s above-ground growth. By comparing the NDVI of the crop being evaluated to that of an N-rich strip in the field, the technology can be used to respond to field variability. As the applicator moves across the field, a built-in microprocessor analyzes the NDVI readings and determines the N requirements that are needed to meet full yield potential. Pre-determined algorithms calculate the amount of N required. The information is relayed to the rate controller to provide variable rate N application in real time as the applicator moves across the field. Ontario researchers are working with an algorithm that was created at the University of Kentucky for soft red winter wheat. Johnson says the trials have been designed to evaluate the algorithm and adapt it to Ontario field conditions. According to previous research in Ontario’s fixed rate trials, the wheat crop shows a response to 150 pounds of nitrogen 60 per cent of the time. With the Greenseeker’s ability to vary the application rate, Johnson is hoping to apply less nitrogen but still match the yield response of a 150-pound application.In the first year of the trials in 2013, the system didn’t produce a positive economic response. Johnson suspects that they didn’t set the target rate high enough. “In many fields, a fixed rate with a higher rate than what a Greenseeker applied was our most economical rate,” he says. The target was set at a higher rate in 2014, but Johnson was not comfortable with the much higher amount of nitrogen that was applied, which reached 200 pounds in some areas. While it didn’t achieve the desired results, Johnson is still intrigued by the system. “I would look at the field, walk it and see a nice uniform field, and then you get the NDVI map and there were all kinds of differences,” says Johnson. “How real are those differences? We don’t know that.”Dr. Lloyd Murdock, a soil specialist at the University of Kentucky, had a similar experience when writing the algorithm. Murdock received a grant to run experiments with the Greenseeker, which was developed at Oklahoma State University. Murdock says farmers were generally doing a good job of estimating the amount of N needed for the crop by counting the tillers and looking at the colour. The method, however, is highly subjective and doesn’t address the variability in the field. “You have an instrument that could actually look at the crop and see what it is doing and make that assumption, not on a subjective factor, but on the factor on how it has grown and what it’s done,” says Murdock.He evaluated the technology using algorithms developed in Virginia and Oklahoma. Calling the initial results “OK,” he notes that they couldn’t beat the results of the old system. The researchers applied less N using the two algorithms, but the yields were lower. “When we did the economics, we were getting less money. So it became apparent to us that the algorithm has to be a regional thing,” says Murdock. In a process to regionalize the system for Kentucky (which took approximately four years), the researchers conducted several small plot trials with different rates of N applied at different times around the jointing stages of the crop. They used hand-held Greenseeker units to record the readings that were then used to develop the algorithm and realize the technology’s potential of applying N more effectively. The algorithm was then tested on farmers’ fields and was found to be better than the old method by raising the yields and economic returns. “Two years ago, when we had a lot of N carryover from a poor corn crop and lodging of the wheat plant . . . that year was terrible,” recalls Murdock. “But if you used the Greenseeker, it picked up that difference and didn’t put much N on. It’s based on the fact the technology is better than our eyes.” With a yield gain of about five to seven bushels per acre, Murdock notes that the $20,000 Greenseeker system isn’t for everyone. Farmers who have 1,000 or more acres and who plant wheat every year would be more likely to see a quick return on the investment. Johnson’s team is also seeking ways to regionalize the algorithm for Ontario. They’re using hand-held units to record NDVI readings from sites that have received various amounts of N, a method similar to the Kentucky algorithm. The results would then be correlated with the yields. “If we get enough of these sites, maybe we can actually find out what that curve should look like under Ontario conditions,” adds Johnson. Another important factor is to ensure that nutrients such as sulphur and manganese aren’t deficient. The Ontario researchers learned that the Greenseeker will read them as a nitrogen deficiency and apply N where it won’t help at all. “We need to make sure that we solve those issues before the Greenseeker technology is going to do what we want it to do,” says Johnson. In addition to the Greenseeker technology, they’re also flying unmanned aviation vehicles with multi-spectral cameras to see if that might be a more effective way of gauging the variability in the fields. “Putting a prescription map into an applicator might be just as effective, or even more effective than trying to read it on the go because there is always the challenge of the lag time between the sensor readings and when we change the rate,” says Johnson. “It’s quick, but is it quick enough? There are lots of questions we’re still trying to address.”