The interdisciplinary team, led by Jonathan Lynch, distinguished professor of plant nutrition, will combine a suite of technologies designed to identify phenotypes and genes related to desirable root traits, with the goal of enhancing the breeding of crop varieties better adapted for nitrogen and water acquisition and carbon sequestration.
The project is part of ARPA-E's Rhizosphere Observations Optimizing Terrestrial Sequestration, or ROOTS, program, which is aimed at developing crops that enable a 50 percent increase in carbon deposition depth and accumulation, while also reducing nitrous oxide emissions by 50 percent and increasing water productivity by 25 percent.
The ROOTS program website explains that while advances in technology have resulted in a tenfold increase in crop productivity over the past century, soil quality has declined, leading to a soil carbon debt equivalent to 65 parts per million of atmospheric carbon dioxide. This soil carbon debt increases the need for costly nitrogen fertilizer, which has become the primary source of emissions of nitrous oxide, a greenhouse gas. The soil carbon debt also impacts crop water use, increasing susceptibility to drought stress, which threatens future productivity.
Given the scale of domestic and global agriculture, there is tremendous potential to reverse these trends by harnessing the photosynthetic bridge between atmospheric carbon, plants, microbes and soil. Advanced root systems that increase soil organic matter can improve soil structure, fertilizer use efficiency, water productivity, crop yield and climate resilience, while mitigating topsoil erosion – all of which provide near-term and sustained economic value. | READ MORE
While lingering cool soil temperatures slowed development of the earliest planted corn, emergence was generally good for most fields. With the lack of rainfall in May, corn that had been planted when parts of fields were not quite fit or had not been fully planted into moisture may have struggled to emerge or emerged late. While generally minor overall, this resulted in variability in some fields. Some growers on heavier soils reported emergence issues following the cool weather and rainfall of May 14-15th. A small amount of replanting was reported to have occurred.
The annual OMAFRA Pre-Sidedress-Nitrate-Test (PSNT) survey was conducted at the V3-V4 stage on June 6-7th. With an overall average soil nitrate concentration of 11.2 ppm, levels were average to slightly higher than average. Given the lack of rainfall and low potential for soil saturation during May and June, nitrate losses from leaching or denitrification were unlikely. Below average precipitation in June maintained a wide window for weed control and sidedress nitrogen applications. With the exception of some moisture stress appearing on soils with poor water holding capacity in the drier parts of the province, the corn crop generally looked good and uniform through the end of June.
While some parts of the province received rain in July, many areas continued to be below normal, particularly the Bruce-Grey, Niagara and Central Ontario regions. Fields or parts of fields in these regions were beginning to show signs of moisture stress as corn leaves would wrap. There were some concerns as corn entered the moisture-sensitive tassel and pollination stages during the hot and dry conditions around the week of July 18. Some localized areas received thunderstorm related precipitation around this period.
During grain fill, there were reports of “tip-back” where several rows on the cob tips failed to pollinate and silks remained green. Warm temperatures continued to push crop development. As corn continued the grain filling process, significant rainfall events started to occur during August, with monthly precipitation totals ranging between 100-200 per cent of normal for large portions of the province. Despite this, leaf diseases, where present, typically remained at low levels. Between timely planting and above average heat unit accumulation, there were few concerns about crop maturity as August came to a close.
Silage harvest started in earnest in many areas during the week of September 12, with the exception of some early harvesting of moisture stressed crops. September remained generally dry, which resulted in good silage harvest conditions. Some reported whole plant moisture being drier than what had been anticipated at the start of harvest. Yields were reported to be below average in areas with little rainfall and on soils with poor water holding capacity, while yields in other areas were reported to be average. Lab analysis results suggested vomitoxin levels in silage were higher than normal.
The annual OMAFRA grain corn vomitoxin survey was conducted from September 23 to 30th. The survey indicated elevated vomitoxin levels with 26 per cent of samples testing above two ppm. Long-term averages for this category run between five and 10 per cent, suggesting some extra monitoring for grain management and feeding may have been required in 2016. Risks may have been elevated from the wet and humid conditions that persisted from August to early September. Poorer pollination of ear tips which resulted in silks remaining green and husk tips that tended to remain tight may have also contributed to this. Western bean cutworm feeding that opened husks for mould establishment was prevalent in many areas as well. The incidence of samples testing higher for vomitoxin decreased east of Toronto.
As the growing season came to a close, heat unit accumulation ranged from average to 100-200 Crop Heat Units (CHU) higher than normal. Coupled with dry weather, corn harvest started early with some combining beginning as early as the last week of September. Harvest started in earnest around October 15, and progressed quickly as dry conditions prevailed for most of the province, resulting in a wide harvest window. Most growers reported moisture levels lower than what was typical for the time of year, and excellent test weights. With the exception of some localized pockets where soybean harvest was delayed, harvest was wrapping up in most areas by the end of the first week of November. Many growers reported yields that were above expectations considering the hot, dry growing season, with the exception of those on soils with poor water holding capacity, or regions which received well below average precipitation. As of December 14, Agricorp corn yields have been reported on 78 per cent of insured acres with an average yield of 167 bu/ac. This compares well to the 10 year average yield of 167 bu/ac for those reported acres.
Researchers at the University of Missouri have determined the mechanisms corn plants use to combat the western corn rootworm.
The technology is incredibly, and increasingly, valuable to Eastern Canadian growers, where 2,035,000 of the total 2,295,000 acres of corn were planted to Bt hybrids in 2015. But the ever-present risk of the development of insect resistance to the technology is keeping the industry on its toes.
While resistance hasn’t yet developed in European corn borer (ECB) populations in North America, reduced susceptibility has been noted in some populations of corn rootworm, according to Jocelyn Smith, a research associate in field crop pest management at the University of Guelph’s Ridgetown Campus.
But resistance can be delayed with proper management. In Canada, stewardship of Bt technology takes the form of insect resistance management (IRM) plans, which chiefly involve maintaining refuges to delay the development of resistant insect populations.
Stewardship also entails rotation of traits in the field, as well as the use of stacked traits.
“The most important thing we can do with this issue is educate growers more about the risks they’re taking if they continuously use traits for rootworm,” Smith says. “Their sheer numbers and biology give them advantage.”
This is a message familiar to Eastern Canadian corn producers, and they’ve taken it to heart. The Canadian Corn Pest Coalition (CCPC) – made up of academics (such as University of Guelph researchers), the Canadian Food Inspection Agency (CFIA), the provincial ministries of agriculture, and industry representatives – has been conducting surveys on insect resistance management compliance since the late 1990s.
Until 2012, those surveys were conducted in alternating years with CFIA IRM compliance surveys, but that year, stewardship compliance rates were so high CFIA discontinued them unless “in future, industry practice shifts from using blended refuge.”
But the CCPC’s bi-annual survey continues. “The increase in compliance with refuge area requirements from 2013 to 2015 occurred in all three provinces and now stands at 91 per cent in Ontario, 90 per cent in Quebec and 91 per cent in Manitoba,” the 2015 report concluded.
According to the same report, compliance tended to be higher in the 35 to 44 age category, but lower among producers who believed stewardship requirements to be “only somewhat important.” In addition, the report indicates awareness of stewardship requirements has declined since 2013, particularly in Ontario; compliance was also lower among those who believed they did not understand requirements.
More education needed
Cindy Pearson, national manager of the CFIA’s Plant Biosafety Office, says the onus is on companies marketing Bt products to educate producers regarding the need for delaying resistance and how refuges work.
“IRM plans are the responsibility of the company to whom the Bt corn product has been authorized, and CFIA receives specific reports from companies that
detail their various activities on that front,” Pearson says.
The survey notes refuge-in-a-bag (RIB) hybrids, which contain the required percentage of refuge seed, resulted in significantly higher compliance rates after their market introduction several years ago. The market has also changed with the introduction of stacked hybrids with multiple Bt traits or modes of action against the insect pests.
“There are currently three traits available for corn rootworm control,” she says. “Where we have growers with long-term use of two of those traits on their own (not in a stacked product), we’ve started to
notice some shifts in susceptibility when we test those populations in the lab.”
This doesn’t necessarily mean producers can see resistance developing in the field, but it’s still a red flag.
“We need to focus on informing continuous corn growers that the three-year limit is important,” Smith says. “We may have had a situation where a grower has used a single trait for years and it’s compromised, so then when they use the stack there’s only one viable trait remaining against the pest.”
Smith also emphasizes monitoring as a key aspect of stewardship. “If you are growing corn on corn, scout your corn late in the season and if there’s less than one beetle per plant you might be able to get away without using transgenics,” she says. “You might be able to hold off on using some of the technology in the following year.”
Smith also recommends rotating management options — in other words, soil insecticides and Bt traits.
“And again in season, keep an eye on the pest situation in the crop. For ECB and rootworm, you need to monitor whether they are being controlled by the Bt hybrids or not. If they are not, you need to notify the CCPC and the trait provider,” she says.
As long as they use Bt technology, producers are on notice to use it well. Resistance is in nobody’s interest except the insects.
The OMAFRA field crops team conducted its annual vomitoxin survey to assess the presence of corn ear mould and grain vomitoxin in the 2016 corn crop. Vomitoxins can be produced by Gibberella and Fusarium ear moulds and can be disruptive when fed to livestock, particularly hogs.
A total of 121 samples were collected from southern to eastern Ontario from Sept. 23 to 30. In most cases, five consecutive ears were pulled from four random locations throughout a field. After recording pictures and rating ears for the presence of moulds and insect or bird feeding, samples were placed into driers as soon as possible after collection. Dry ears were shelled and mixed through a sample splitter, and delivered to SGS Agrifood Laboratories in Guelph for vomitoxin (DON) analysis.
Of the 121 samples collected:
- 48 per cent (58) had a DON concentration of less than 0.5 ppm;
- 26 per cent (31) had a DON concentration between 0.5 and 2.0 ppm;
- 26 per cent (32) had a DON concentration of 2.0 ppm or greater
Visual mould symptoms were much more prevalent in the 2016 survey than what has been observed in recent years. Similarly, vomitoxin analysis revealed DON concentrations that were higher than surveys from the past couple of harvest seasons, with the most recent year of comparable results being 2011 (Table 1). These results suggest extra vigilance in monitoring and managing DON concentrations in corn may be required in 2016. While some samples with elevated levels of DON were present across most regions sampled, in general there appeared to be a greater incidence of elevated DON levels for samples collected from southwestern Ontario.
Table 1. Vomitoxin (DON) results from the past six OMAFRA vomitoxin surveys.
|< 0.50 ppm
|0.50 to <2.00 ppm
|≥ 2.00 ppm
Feeding on ears by pests, particularly western bean cutworm (WBC), incomplete pollination, and open ears present an opportunity for greater mould infestation. While visual mould symptoms were generally more severe where ear feeding from WBC was present, mould symptoms and elevated vomitoxin levels were also observed on some ears and samples with little or no feeding injury. While WBC feeding may predispose risk, monitoring will be important in a higher risk year such as 2016 whether or not WBC feeding was present.
This survey does not fully capture all regions of the province, and results can vary locally from field to field depending on hybrid, planting date, insect feeding or fungicide practices. These results may not fully capture what is occurring in your fields, and therefore monitoring is recommended. If you suspect grain vomitoxins may be present, it is recommended to sample ears in a similar fashion as described above, hand shell, mix, and submit a grain sample as soon as possible after collection to one of the several labs in the province that test for vomitoxin.
When ear rot is present, the following harvest, storage and feeding precautions are advisable (Adapted from OMAFRA Pub 811, Agronomy Guide for Field Crops):
- Harvest as early as possible especially susceptible hybrids.
- If insect or bird damage is evident, harvest outside damaged rows separately. Keep and handle the grain from these rows separately.
- Adjust harvest equipment to minimize damage to corn, and to remove smaller end kernels or those that have been damaged from mould or insect feeding. Clean corn thoroughly to remove pieces of cob, small kernels and red dog.
- Clean bins before storing new grain and cool the grain after drying. If possible, segregate corn based on vomitoxin content to help match end use.
- Check stored grain often for temperature, wet spots, insects and mould growth.
- Exercise caution when handling or feeding mouldy corn to livestock, especially to hogs. Pink or reddish moulds are particularly harmful. Test suspect samples for toxins. Work with a nutritionist to manage vomitoxin levels in feed.
Appreciation to the Grain Farmers of Ontario and SGS Agrifood Laboratories in Guelph for their support of this survey and analysis, and to the OMAFRA field crops team, industry participants and growers that assisted in the co-ordination and collection of samples.
As corn producers plan for harvest, they should be accessing their fields for stalk rot and ear moulds, reminds the OMAFRA Field Crop team. The distribution and prevalence of these diseases vary from year to year but they are present every year, especially when the crop is under stress (water stress, insect feeding, etc.). It goes without saying that this year was very stressful and in many cases, corn plants had to endure not one stress but multiple stresses and we are observing ear mould infections (Gibberella and Fusarium primarily) in many fields across the province. They range from light to significant levels therefore, in order to manage and minimize the effects of these ear rot diseases, it is critical to assess fields before harvest. Growers should assess fields each year, because these pre-harvest assessments can alert them to potential problems and provide time for livestock producers for example, to segregate, obtain alternative grain, or hold onto stored corn from the previous year.
Scouting practices are similar for all corn ear rots. Begin scouting fields at late dent stage to determine their presence and severity. When scouting, randomly select plants and pull back the husk to examine the entire ear. A quick method is to select 100 plants across the field (20 ears each from five different areas). For each ear, be sure to peel back the husks and examine the entire ear. Fields with 10 per cent of ears having significant mould growth should be harvested sooner than later.
Leaving diseased grain in the field allows the ear rot fungi to keep growing, which will increase the risk of mouldy grain and mycotoxin contamination. Most ear rot fungi continue to grow (and, if applicable, produce mycotoxins) until the grain has less than 15 per cent moisture. In severely infected fields, it may be worthwhile to harvest grain at higher moisture and then dry it to less than 15 per cent to minimize further mycotoxin accumulation.
Preventing ear rots and mould is difficult since weather conditions are critical to disease development. Although some tolerant hybrids are available, none have complete resistance. Crop rotation can reduce the incidence of Diplodia ear rot. Cultural practices have been shown to have limited success in preventing ear and kernel rots. Minimize these diseases through timely harvest and proper drying and storage.
When ear rot is present, the following storage and feeding precautions are advisable:
- Harvest as early as possible.
- If bird damage is evident, harvest outside damaged rows separately. Keep and handle the grain from these rows separately.
- Adjust harvest equipment to minimize damage to corn. Clean corn thoroughly to remove pieces of cob, small kernels and red dog.
- Cool the grain after drying.
- Clean bins before storing new grain.
- Check stored grain often for temperature, wet spots, insects and mould growth.
- Control storage insects.
- Exercise caution in feeding mouldy corn to livestock, especially to hogs. Pink or reddish moulds are particularly harmful. Suspect samples should be tested for toxins.
Gibberella ear rot: The most common and important ear mould in Ontario is Gibberella zeae which is the sexual reproductive stage of Fusarium graminearium. This fungus not only infects corn, but also small grains such as wheat, and can survive on soybean roots. In most cases, Gibberella begins at the ear tip and works its way down the ear. Also, the husks from infected ears are often tightly adhered to the ear. Although the fungus can produce a white-coloured mould, which makes it difficult to tell apart from Fusarium kernel rot, the two can be distinguished easily when Gibberella produces its characteristic red or pink colour mould. Infection begins through the silk channel and thus, in most cases starts at the ear tip and works its way down the ear. In severe cases, most of the ear may be covered with mould growth. Corn silks are most susceptible two to 10 days after initiation. Warm and wet weather during this period is ideal for infection.
Fusarium kernel rot: Unlike Gibberella, Fusarium infected kernels are often scattered around the cob amongst healthy looking kernels or on kernels that have been damaged by corn borer or bird feeding for example. Fusarium infection produces a white to pink or salmon-coloured mould. A "white streaking" or "star-bursting" can be seen on the infected kernel surface. Although many Fusarium species may be responsible for these symptoms, the primary species we are concerned about in Ontario is Fusarium verticillioides (formerly Fusarium moniliforme). Fusarium survives in corn debris. The significance of this fungus is that it produces a toxin called fumonisin that has been shown to cause cancer in humans. The environmental conditions that favour disease development are warm, wet weather, two to three weeks after silking.
Diplodia ear rot: The characteristic ear symptom of Stenocarpella maydis and S. macrospora infection is a white mould that begins at the base of the ear and will eventually cover and rot the entire ear. Mould growth can also occur on the outer husk which has small black bumps (pycnidia) embedded in the mould. These reproductive structures are where new spores are produced. Pycnidia (the small, black, spore-producing structures of the fungus) overwinter on corn residue and are the source of infection for the subsequent corn crop. Dry weather before silking, immediately followed by wet conditions, favour Diplodia infection.
Penicillium ear rot: Penicillium rot (Penicillium oxalicum) produces a light blue-green powdery mould which grows between the kernels and cob/husk surface. Infected kernels could become bleached or streaked. Penicillium ear rot can be a serious problem if corn is stored at high moisture levels (greater than 18 per cent).
Table 1. Common ear rots and moulds that occur in Ontario and the primary mycotoxins they produce.
||Signs and symptoms|
|Aspergillus||Aflatoxin||Hot, dry||Olive green spores on ear|
Moderate to warm temperatures during silking,
wet periods prior to harvest
|White to purple mold, scattered across ear;
Starburst pattern in kernels
|Gibberella||Deoxynivalenol (vomitoxin) and zearalenone||Cool, wet weather||Pink to white mycelial growth|
|Diplodia||None currently known in U.S. and Canada||Moderate temperatures and wet during silking||White mycelial growth on ear and husk; black pycnidia in cob|
|Penicillium||Ochratoxin (only some species)||Wet, humid conditions post grain-fill||Blue-gray fungal spores|
|Nigrospora||None||Damaged corn||Black spores, grey mycelia, shredding cob|
|Cladosporium||None||Wet weather near harvest||Dark-green to black kernels|
|Trichoderma||T-2 (only some species)||Damaged corn||Blue-green spores growing in and on kernels; may cause sprouting|
More information can be found in OMAFRA’s Field Crop Agronomy Guide – Publication 811, or Crop Protection Network Publication “Corn Management Disease Series – Ear Rots” at CropProtectionNetwork.org.
The dry, hot summer, with drought-like conditions that persisted well into August, will reduce yields for both crops, says Henry Van Ankum, chair of the board of the Grain Farmers of Ontario.
He has a large-scale corn, soybean, and wheat farm of his own near Alma, north of Guelph.
While it is the case that certain pockets of land in the Guelph area will yield better than others, and that conditions in the fields are variable, it is safe to say that this will not be a banner year for growers, Van Ankum indicated.
“It’s really variable, depending on your soil type,” he said. “But certainly on your gravely soils around Guelph, it was definitely too dry at a critical period, when the corn was tasseling and the cob was pollinating. There won’t be a fully formed cob on some of that corn.” | READ MORE.
Friday, Cheema and four students working on the project visited the corn plots they are growing at the Forestry and Agrifoods Agency’s Western Agriculture Center and Research Station in Pynn’s Brook.
The project, in its second year, involves the study of five silage varieties of corn, a crop that provides high energy for dairy cows.
“The objective is to find a good variety that can be successfully grown here,” said Cheema, standing in front of row after row of tall corn stalks.
The research is also to determine which varieties have the capability to get more nutrients from the soil. | READ MORE.
In Newfoundland and Labrador it’s a real struggle to grow corn and shipping in silage for livestock is a huge cost for local farmers. Mumtaz Cheema, an associate professor at the Grenfell Campus of Memorial University in Corner Brook, N.L., wants to help change all of that.
One of the first things Cheema recalls noticing when he first came to Newfoundland in 2013 was the high cost of milk, compared to the rest of Canada. When he had the chance to meet a director of the Dairy Farmers of Newfoundland and Labrador, he soon learned about the difficulties cattle producers faced in growing their own feed in a very low heat unit climate. Seeing an opportunity to make a real difference for the province’s farming community, he immediately set out to research ways to evaluate regional corn silage hybrids.
“There was very little information available,” Cheema recalls. “Agriculture research in the province is still at infancy.”
The very first challenge he faced was simply generating a list of 2,000 to 2,200 heat unit hybrids that would be capable of maturing before the end of the growing season. There weren’t more than 10 options in total. After consulting with Vanessa Kavanagh, alternative feeds coordinator with the province’s Forestry and Agrifoods Agency and collaborator in this project, that list was whittled down even further.
“Because everything comes through the ferry, some were not available,” Cheema explained. “I chose these five because I could actually get the seed for these five.”
DKC-2317 and DKC 26-28 by DeKalb, Fusion and Yukon by Elite, and A4177G3 by Pride were seeded on June 4, 2015, at a rate of roughly 36,000 seeds per acre. Cheema says they had to grow the plot under plastic, so they used a Samco three-in-one plastic laying machine vacuum planter and a perforated clear polymer mulch that eventually degrades in season. All corn hybrids were Roundup Ready, so weed control in the plot was comparable to farm practices. Before harvesting on Oct. 16, 2015, however, a number of assessments were conducted. Cheema says that farmers on the west coast of the island additionally have to contend with low soil fertility, so he also needed to closely assess nutrient use in the trial.
“I wanted to do this experiment at two sites, one with low phosphorus and one with high phosphorus, but I couldn’t because most farmers simply blanket apply nutrients and I couldn’t find a single point that is phosphorus deficient,” he explained. “So we applied manure in keeping with farmers’ practices.”
Cheema says applying inorganic 0-45-0 fertilizer, a low-phosphorus manure collected from one nearby dairy farm, a high-phosphorus manure collected from another local dairy farm, and no manure as a control on each hybrid, over four replications, generated a significant amount of data for his team to analyze over the winter. Especially since they collected root zone soil samples from every replicate two weeks after emergence, at the six-leaf stage, at silking, and at black layer stage. He also had his research team install tubes, which allowed him to monitor in-situ underground growth using a root scanner at intervals throughout the growing season.
“We were trying to see how the manure affects root morphology, plant biomass, P uptake in plants and so we collected soil samples to analyze the phenolics, enzymes or microbial colonies that impact phosphorus availability,” he explains. “We installed the acrylic tubes to measure the root traits if there is any correlation between biomass and root morphology.”
Analyzing all of this data, along with leaf area and leaf chlorophyll and greenhouse gas emission measurements, will take many months still. Cheema is waiting on feed quality analysis results because local lab services are limited. He’s essentially had to work at establishing a qualified facility of his own instead of submitting samples last year, as many mainland researchers would do. However, he believes collecting this abundance of data will pay off in the end as the trial harvest data has already produced unexpected results.
When assessing biomass last year, surprisingly, one of the shorter day hybrids significantly out yielded the higher crop heat unit (CHU) competitors. At just 2,150 CHU, Yukon produced 20.84 tonnes per hectare (t/ha) upon harvest. The other 2,150 CHU hybrid, DKC 26-28, followed close behind it with 20.27 t/ha. Meanwhile the 2,175 CHU hybrid, A4177G3, performed the poorest of all at 15.7 t/ha. With both the longest and shortest day hybrids falling in the middle of the pack, Cheema believes it’s quite clear that there’s a lot more to selecting a high-performing hybrid in this
climate than assessing day length.
“Heat units are only one factor,” he says. “Sometimes the genetic potential of hybrids allows them to perform better.”
Cheema believes that close analysis of the root morphology of these plants may reveal a correlation between the root growth of each hybrid and final yields. Though there’s still a great deal of work to accomplish, when he’s done, it’s very possible his findings may have even greater implications than simply benefiting the corn silage producers of Newfoundland and Labrador alone.
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