March 3, 2016 – There are some clear advantages to seeding canola early, including high yield and mitigating pest issues. This spring ensure that your planting equipment is ready to go early in the season and get your canola crop off to a quick start.
Ideal planting dates in Ontario are typically in late April and early May. Germination can occur at soil temperatures as low as 1 C or 2 C, but emergence will be more rapid at higher temperatures. Data posted by Canola Council of Canada suggests that if temperatures stay at 3 C it may take up to 14 days before full germination is achieved. At 6 C it will take only eight days. However, beginning seeding at 3 C or 4 C soil temperature is a reasonable target if soil conditions are fit for planting and temperatures are expected to rise. Even though soil conditions may be cool, early seeding will typically result in higher yields as long as adequate plant stands are established.
Soil conditions are, of course, of primary importance. Good soil moisture in the seed zone and adequate seed-to-soil contact are important for emergence. Residue should be evenly distributed and a firm seed bed will improve seed placement. With late seeding there may not be adequate moisture to seed at the recommended half-inch to one-inch depth, and deeper seeding will reduce emergence rates.
Spring frost can be an issue because the growing point is above ground and exposed between the cotyledons (seed leaves). However, a light frost may be tolerated, particularly if canola has reached the three or four leaf stage. If plants have “hardened” over several days of cold weather, they may be more tolerant of frost than rapidly growing plants. On the other hand, seeding late in May can lead to flowering during hot weather in late June and July and this temperature stress can have a huge impact on yield.
Good stand establishment and rapid, early growth is ideal for mitigating issues caused by insect pests. Flea beetle emergence from overwintering sites will peak at soil temperatures of 15 C, and it may take up to three weeks for all adults to emerge. Insecticide seed treatments control flea beetle for about three to four weeks, but slow early growth can mean that protection is lost before canola has passed out of the susceptible growth stage. At the three to four leaf stage, canola should be better able to outgrow the feeding damage.
Rapid, early growth is also ideal where swede midge is a concern. Swede midge adults emerge from the soil in mid-May to early June and larvae feed on the growing point at the center of the plant. A crop that bolts early may escape significant damage, and risk of damage is not a concern after flowering is initiated on secondary branches. Canola planted in late May or early June in areas with a history of swede midge faces high risk of damage.
Consider what the ideal seeding rate is for the given conditions. In an average year somewhere between 40 and 60 per cent of the planted seeds will emerge. The ideal plant population is seven to 13 plants per square foot, or 4.5 to six plants per foot of row on 7.5-inch rows. There are benefits to having a dense stand, including increased light capture, mitigating losses to insect pests, and less branching leading to earlier and more even maturity. Your seeding rate should factor in the seed size, compensate for low emergence rates, and provide a final stand well within the ideal population for the best final yield results. Note that at a seed size of 4.75 g and seeding rate of five pounds per acre, a typical 60 per cent emergence rate will result in around just four plants per foot of row. For very early or very late plantings the seeding rate could be bumped up by five to 10 per cent.
A uniform stand will likely yield more than a non-uniform stand, even at the same plant population. In uneven stands the plants will compete for soil and light resources, and will branch more in thin areas causing delayed and uneven maturity. After the crop emerges, determine the plant population and percent emergence, and note the uniformity of the crop. If there is a regular pattern across the field, uniformity may be affected by issues with your planting equipment. Take notes so you can make further improvements next year.
There’s another root rot pathogen in the neighbourhood. It’s called Aphanomyces euteiches. It loves peas, lentils and waterlogged soils. And it’s tough to deal with because its resting spores can survive in the soil for many years. Although Aphanomyces has been present in Manitoba since the late 1970s, researchers only recently identified it in Saskatchewan and Alberta. Now they are at work on some new strategies for managing it.
Aphanomyces euteiches is an oomycete, or water mould, which is a fungus-like organism. It produces one generation in a season. “The oospores are the primary inoculum left behind in the soil or decaying host tissue. They are thick-walled, very resistant resting structures. Reports in the literature indicate they can survive in the soil from five to upwards of 20 years, depending on weather conditions,” explains Syama Chatterton, a plant pathologist with Agriculture and Agri-Food Canada (AAFC) in Lethbridge, Alta.
“A susceptible host plant releases root exudates and signals into the soil. Oospores respond to those signals and germinate. Through a complicated germination process, they eventually produce zoospores, which are single cells with two flagella that help them swim.” They swim in soil water films to the host root and attach themselves to it.
“Then they produce hyphae, the fungal strands that penetrate into the root, and very rapidly begin colonizing it.” They break down the root tissues, feeding on the nutrients. Once they have used up all the nutrients in the root, they form oospores.
The whole life cycle can be completed in about three weeks if temperature and moisture conditions are ideal. Infection can occur at any stage of the host’s development, with the timing depending on the environmental conditions.
Soggy, warm conditions are ideal for infection. “Aphanomyces often occurs in a complex with other root rot pathogens, like Fusarium, Pythium and Rhizoctonia. They all like moist conditions, but the oomycetes – Pythium and Aphanomyces – do even better with excess moisture,” says Faye Bouchard, provincial plant disease specialist with the Saskatchewan Ministry of Agriculture. On the Prairies, optimal soil temperatures for Aphanomyces infection (22 to 27 C) are typically reached by about July (see Table 1).
Chatterton has done Aphanomyces host range work with Sabine Banniza at the University of Saskatchewan. They have found that peas and lentils are both highly susceptible, whereas dry beans, fababeans, chickpeas and soybeans all have pretty good resistance. Alfalfa is somewhat susceptible, but some alfalfa cultivars are resistant. In 2015, Chatterton surveyed alfalfa crops grown on fields that have had peas in the rotation and found that the alfalfa roots were very healthy, suggesting that Aphanomyces is probably not a big concern for alfalfa.
“Aphanomyces has been around in Canada since the 1930s. But we just found it in Saskatchewan in 2012 in peas,” Bouchard notes. “Then we started doing more surveys for it, and Alberta started looking for it [and found it in 2013].” These surveys show the pathogen is fairly widespread in both provinces.
So why has Aphanomyces root rot suddenly become an issue? “My hypothesis comes down to three reasons that have all come together in a perfect storm,” Chatterton says.
“The first reason is that we’re reaching the point where most places in Alberta and Saskatchewan have had a good 25-year cropping history of either peas or lentils. So, if producers are using good rotational practices with a pea or lentil crop once in every four to five years, then some fields would have had a pea or lentil crop six to seven times, or more often if they have tighter rotations. If a field started with a low inoculum level…the amount of inoculum would gradually build up every time a susceptible host crop was planted because the oospores can survive for a long time. It would take about six to seven cropping cycles to reach a threshold level of inoculum where it is more widespread throughout the field and can cause visible damage,” she explains.
“The second reason is that we had several really wet springs in a row, and Aphanomyces is dependent on having saturated soils in order to infect. So you get increased infections because the environmental conditions are right, and the inoculum load in the soil increases quite quickly.”
And the third reason is a detection issue. “In previous root rot surveys, they were taking pieces of roots and plating them out on agar to determine the causal agent. But usually Fusarium over-grows Aphanomyces on the culture, so it can be really hard to confirm Aphanomyces. I think it was Sabina Banniza who decided in 2012 to do a PCR test [which uses DNA markers specific to Aphanomyces euteiches]. That was the first time we were able to confirm Aphanomyces in [a Saskatchewan sample]. For our Alberta surveys in 2013 and onwards, we’ve expanded to using that PCR test. It has definitely improved detection of Aphanomyces.”
In Chatterton’s root rot surveys for 2013, 2014 and 2015, root rot was found in about 70 per cent of the surveyed fields each year, but disease severity varied greatly from year to year. The highest root rot levels occurred in 2014 because it was a particularly wet year. Chatterton says, “In 2014, we found that root rot was common and widespread throughout Alberta. The results from the PCR tests showed Aphanomyces was present in about 44 per cent of all fields in Alberta and in 60 per cent of fields that had root rot symptoms.”
The PCR analysis of the 2015 Alberta samples is not yet complete, but the field surveys showed root rot severity was definitely lower than in 2014, due to the very dry conditions in 2015.
The Alberta surveys also show that “Aphanomyces-positive fields are more common in the Black and Gray soil zones that are more typical of central Alberta. I think that is because they have had a pretty long history of pea production there, and those areas tend to be wetter than southern Alberta,” Chatterton notes. “In southern Alberta’s Brown soil zone in 2014, only about 18 per cent of the fields were positive.”
Although Saskatchewan didn’t do a formal root rot survey in 2015, the dry conditions in the spring and early summer likely reduced the amount of disease. Bouchard didn’t see as much root rot in the field, she didn’t get as many inquiries about it from growers, and fewer samples were submitted to the ministry’s Crop Protection Lab.
Difficult to diagnose in the field
Trying to figure out which root rot pathogens you have in your field isn’t easy. Aboveground, they share the same symptoms, like poor emergence, wilting, yellowing and stunting. The belowground symptoms are usually a confusing mix caused by a complex of pathogens.
In the lab, if you infect plants with only Aphanomyces, the symptoms are distinctive. “The whole root system will have a honey-caramel discoloration. And the classical symptomology is that the epicotyl, which is the portion between the point of seed attachment and the green stem, becomes very tightly constricted and has that same honey-brown colour, which stops abruptly right at the green stem,” Chatterton explains. “Also, because the disease causes decay of the entire root cortex but not the vascular system, oftentimes if you pull up the plant from the soil, only the white vascular bundle is left and the rest of the roots are gone.”
In the field, Fusarium species tend to colonize tissue that Aphanomyces has already started to infect, producing mixed symptoms. “The roots will look black and will be pruned away; Fusarium causes pruning of the roots. So you get an ugly mess of a black taproot and brown decaying lateral roots,” Chatterton says. “A good way to check for Fusarium is that it causes red colouring in the vascular system.”
When a root rot infection is advanced, it is especially difficult to figure out the original cause. “Not only are the roots rotting and the plant dying, but there could be multiple root rot pathogens as well as saprophytes, which are fungal organisms that live on the decaying and dead plant material,” Bouchard says.
She adds, “The other difficulty is that it is hard to separate out the damage that excess moisture causes to the crop, even without any pathogens present. Lentils and especially peas don’t like wet feet, when the plant is sitting in too much water. Those conditions alone will mean that the roots won’t develop as well and probably won’t form nodules as nicely, and the above-ground plant parts will probably be yellowing, stunting and wilting. But those wet conditions stress the plant, so if a pathogen is present, it will probably cause even more damage because of the stress.”
The best way to tell which root rot pathogens are present is to send samples to a diagnostic lab, such as Saskatchewan’s Crop Protection Lab, Discovery Seed Labs or BioVision Seed Labs.
Seeking more management options
Researchers in Alberta and Saskatchewan are tackling Aphanomyces from several angles. For example, at the University of Saskatchewan, they are working on developing resistant lines of peas and lentils.
To assess various Aphanomyces management practices in field peas, Chatterton initiated a large study in 2015. The study is taking place at Drumheller, Brooks, Taber, Lethbridge, Saskatoon, and two sites in the Red Deer-Lacombe area. Collaborating with Chatterton are Mike Harding and Robyne Bowness at Alberta Agriculture and Forestry, and Bruce Gossen at AAFC in Saskatoon. The Alberta Crop Industry Development Fund, Alberta Pulse Growers and AAFC, through the Growing Forward 2 Pulse Cluster, are funding the study.
At each site, the study is evaluating seed treatments, cultivar resistance and soil amendments. All sites are in producers’ fields. Six of the seven sites were selected because the fields had a high risk for Aphanomyces root rot; the Lethbridge site only had Fusarium root rot.
The seed treatment trials include different combinations of various products with activity against Fusarium, Pythium, Rhizoctonia and Aphanomyces. The seed treatment for Aphanomyces is ethaboxam (Intego Solo) – a new option that was given emergency use registration on field peas in Alberta, Saskatchewan and Manitoba in 2015.
The cultivar trials involve 20 pea cultivars, including some currently popular cultivars as well as some that are just about to be released.
The soil amendment trials are comparing three possibilities. “We searched the literature for any instance of something that might have some effect against Aphanomyces,” Chatterton explains. One treatment uses calcium, involving spent lime from the sugar beet industry; calcium has reduced zoospore production in greenhouse tests. Another treatment is Phostrol, a phosphite-based product, which has activity against oomycetes and provided some suppression of Aphanomyces in peas in the Pacific Northwest. The third treatment is the herbicide Edge (ethalfluralin), which showed Aphanomyces suppression in some preliminary work a few decades ago.
In the study’s first year, all the cultivars were susceptible to Aphanomyces root rot, as expected from previous greenhouse testing at the University of Saskatchewan.
“The seed treatments and soil amendments gave some promising results early in the season. By about five to six weeks, we could see some nice visual differences in root rot severity between some of the treatments,” Chatterton says. “But by the end of the growing season, the root rots were pretty similar across the board. Some treatments definitely yielded better than others, but we didn’t find any statistically significant differences between treatments.”
With only one year of data in an unusually dry year, it’s too soon to draw any conclusions. Also, Chatterton points to a key challenge with trying to do these types of field trials. “Because the distribution [of Aphanomyces] can be very patchy in fields, we had to choose sites with very high levels of Aphanomyces root rots. I think the inoculum load at some of these sites is too high, and at that level, disease management strategies often aren’t going to work. We could try to find sites that have a lower level of Aphanomyces, but then we won’t be certain that the inoculum has spread throughout the soil [so some plots might have different levels of inoculum].”
The researchers will be repeating the trials in 2016. Then, Chatterton hopes to get continued funding for several more years to determine how low the inoculum levels need to be for the practices to be effective.
In a project funded by the Saskatchewan Pulse Growers, Chatterton and Banniza are determining how much Aphanomyces inoculum is needed to cause different levels of the disease. “Right now, you can submit samples to a lab to find out if Aphanomyces is present or absent, but the lab can’t determine if you have a low or high risk of getting Aphanomyces root rot,” Chatterton says.
“So we want to determine the amount of inoculum needed in the Brown, Dark Brown and Black soil zones to get low, medium or high disease levels. The idea is that interested testing labs could then offer a DNA quantification service for Aphanomyces and be able to use the DNA levels to determine if a field has a low, moderate or high level of Aphanomyces. That should help inform decisions on the length of time peas or lentils might need to be out of the rotation, or whether the grower could look at seed treatments or maybe a soil amendment treatment.”
Advice for growers
At present, the best strategy is to submit plant or soil samples to a diagnostic lab to determine which root rots are causing problems in your fields, and if Aphanomyces is an issue, then use that information in your management decisions.
For fields that are highly infested with Aphanomyces, Bouchard and Chatterton advise waiting at least six years before planting peas or lentils again. Bouchard says, “Hopefully growers won’t have to do that on a permanent basis because there should be more options available as more research is done. One seed treatment, called Intego Solo, is available now, and there are potentially other treatment options coming down the pipeline. And hopefully we’ll get some resistant varieties.”
In the meantime, Chatterton suggests, “If you want to grow a pulse crop [on a field that is heavily infested with Aphanomyces], then fababeans are a really good option because they are really resistant to Aphanomyces.“
For fields with low to moderate Aphanomyces infestations, Chatterton recommends extending pea or lentil rotations from three or four years to perhaps five or six years. She adds, “Those are good fields for possibly using a seed treatment with activity against all the pathogens in the root rot complex, and that should help to boost your crop and keep it healthier.”
Nov. 24, 2015, Mississauga, Ont. – BASF’s HiStick brand inoculants will change its name to Nodulator. Only the name will change, and growers and retailers will see a transition over the next two years.
In 2016, HiStick PRO will transition to Nodulator PRO. In 2017, HiStick N/T liquid and self-adhering peat will transition to Nodulator N/T liquid and self-adhering peat. In addition, Nodulator PRO 225 will launch with seed partners in 2016.
For more information about the Nodulator brands visit www.agsolutions.ca.
July 23, 2015 - Reports of aphid infestations have been common during the past couple of weeks with areas affected throughout Saskatchewan. Many of the reports have been from southwest Saskatchewan in lentil crops. Both pea and lentil appear to be the most affected.
Timing and necessity of insecticide applications should be treated on a case by case basis. Early application of insecticide likely won't provide a yield response but will affect beneficial predators (e.g. lady beetle larvae and adults) and wasp parasites. Late application would have no beneficial result and will be an unnecessary expense as the aphids cannot damage crops that have completed seed filling.
Thiamethoxam, a broad-spectrum neonicotinoid insecticide contributes to better seedling vigour compared (as compared to no treatment) says Clarence Swanton at the University of Guelph.
Do certain seed treatments go beyond protecting young plants from insect pests? That’s an important question, especially if the seed treatment is a neonicotinoid insecticide. Neonics are currently under intense scrutiny by government agencies in many countries and their use is being restricted in some jurisdictions.
It’s clear that at least one neonic seed treatment seems to provide more than insect pest protection in corn, but just what protection it provides and how it does so hasn’t been completely clear.
“Thiamethoxam is a broad-spectrum neonicotinoid insecticide that, in seed treatment form, contributes to better seedling vigour compared to no treatment,” Clarence Swanton, a professor in the department of plant agriculture at the University of Guelph (U of G), says. Thiamethoxam controls a wide variety of commercially important crop pests, and is used as a foliar spray or soil treatment (Actara), or as a seed treatment (contained within Cruiser).
“When thiamethoxam is applied to seed, we see increased germination rates, faster root growth, greater seedling heights and more biomass accumulation, but the physiological mechanisms by which these enhancements occur is not well known,” Swanton explains. “Other researchers have measured the ability of thiamethoxam to do things such as increase the antioxidant capacity of a certain molecule found in corn seedlings, called salicylic acid, which is an antioxidant that plays an important role in the defence against plant pathogens. It is also able to improve plant response to abiotic and biotic stresses, including those caused by the presence of weeds.”
However, thiamethoxam seed treatment may be helping seedlings perform better because it reduces the amount of hydrogen peroxide (H202), a free radical that can accumulate in a seedling due to the stress of having weeds nearby. (Free radicals cause damage in plant and animal cells through a process called oxidation.)
“Thiamethoxam may be elevating the expression of genes involved in natural scavenging and destroying of H202, in addition to genes involved in other metabolic pathways. This is what we wanted to find out more about,” Swanton says.
Swanton and his colleagues have investigated how much better corn seedlings perform with weed pressure, with and without thiamethoxam as a seed treatment. They conducted measurement and analysis at the plant (macro) level, as well as at the molecular level.
In addition to Swanton, the team included Maha Afifi, Elizabeth Lee and Lewis Lukens, a research team at the department of plant agriculture at the U of G. In a laboratory environment, thiamethoxam-treated seeds were planted, with some of the resulting seedlings growing up in the presence of neighbouring weeds (a perennial ryegrass). The researchers harvested seedlings at the fourth-leaf-tip stage, washed the roots, and counted and measured crown roots. Shoots and the entire root system were then bagged separately and dried to determine total shoot and root biomass. Other seedlings were harvested for physiological and molecular analysis.
“At the macro level, we found the treated corn seedlings showed enhanced root development and seedling vigour, with none of the shade avoidance characteristics that typically develop when there are neighbouring weeds present,” Swanton explains. “We believe this was a result of morphological, physiological and molecular processes. This is the first report to identify the mode of action of thiamethoxam within the physiological mechanisms of early crop and weed competition.
“In short, our results suggest thiamethoxam enables corn seedlings to maintain their antioxidant protective system to avoid damage caused by oxidative stress from neighbouring weeds,” Swanton says.
Swanton, Afifi, Lee and Lukens found thiamethoxam reduced H202 accumulation, as well as the subsequent damage caused to cells by its accumulation. “It seems to accomplish this through boosting the capacity of genes involved in scavenging this free radical,” Swanton says. “Preventing the accumulation of H202 and enhancing the entire antioxidant system means the plant experiences less cellular damage caused by abiotic and biotic stresses, such as lower light levels caused by neighbouring weeds. The plants from treated seed don’t have to expend as much energy for cellular repair and the energy can therefore be used for growth and maintenance of plant tissues. So, these results suggest plants from thiamethoxam-treated seeds may be better adapted for survival under harsh environmental conditions.”
Swanton believes these results have several other implications for the role of seed treatments in agriculture.
“Normally, seed treatments are thought of only in terms of insect and disease control, but the results of this study suggest it may be very worthwhile to explore entirely new chemistries and new modes of action in novel seed treatments to enhance free radical scavenging and activate genes involved in the antioxidant defence system,” he says. “It’s clear from our study and the work of other researchers that some seed treatments have this capacity, and that may be critical in the development of crop hybrids and cultivars that are more stress tolerant to weed competition.”
The researchers are now investigating whether soybean seedlings grown from thiamethoxam-treated seed will demonstrate the same responses to weed pressure as those of corn seedlings.
May 14, 2015 - With warmer temperatures and recent rains, the alfalfa and grass growth and development in Ontario is now advancing rapidly, despite a slow start in early April. Older, less healthy stands are beginning to become yellow with dandelions. Many fields that were fall cut are seeing delayed growth that will likely result in reduced first-cut yields.
According to Joel Bagg, OMAFRA forage specialist, grass stands have responded very well to early applied nitrogen with significantly more growth. Most new seedings are in the ground under excellent conditions.
With good overwintering, excellent seeding opportunities and strong seed sales, forage acreage appears to have increased. There was some frost May 14th, but likely with very little damage to established alfalfa stands and new seedings.
May 4, 2015 - Favourable weather and field conditions have resulted in an early start to the 2015 growing season in Manitoba.
Producers across the province have started to seed, with the most progress in the central and eastern regions. Localized areas that had excess moisture in past growing seasons are still experiencing wet conditions and need continued warm dry weather to dry out fields. For the majority of areas in Manitoba, rainfall is needed to assist in crop emergence and growth.
Winter cereal crops generally over-wintered very well, with the spring fertilizer already applied. However, pasture and hay growth has been slow due to dry conditions.
April 8, 2015 - Technological advances by U.S. Department of Agriculture (USDA) scientists are continuing to improve the way beneficial fungi are formulated for use as biopesticides.
Traditionally, biopesticide makers have cultured beneficial species of Beauveria, Isaria, Metarhizium and other fungi on moistened grains like rice or other solid substrates to coax them into forming specialized spores called "conidia."
These conidia are then harvested and formulated into biopesticide products, which can be applied to field- or greenhouse-grown crops as alternatives to synthetic pesticides or used in conjunction with them to delay the pests' development of insecticide resistance.
Over the past decade, however, microbiologist Mark Jackson and colleagues at USDA's Agricultural Research Service (ARS) have experimented with the use of liquid culture fermentation (LCF), an approach that's enabled them to mass-produce stable, effective spore forms called "blastospores" and resting structures such as "microsclerotia."
The researchers' studies have shown that microsclerotia are especially durable, long-lasting during storage, and effective as bioinsecticides and bioherbicides. LCF has also proven to be faster and more economical to use, yielding blastospores or microsclerotia in two to three days versus the ten to fourteen days needed to produce conidia using the traditional culture methods, says Jackson. He is with the ARS National Center for Agricultural Utilization Research in Peoria, Illinois. Replacing hydrolyzed casein and other expensive nitrogen sources with low-cost cottonseed flour also reduces production media costs by 80-90 per cent, he adds.
Jackson's recent collaborations with visiting scientists Gabriel Mascarin (Brazilian Agricultural Research Corporation, a.k.a. "EMBRAPA") and Nilce Kobori (National Council for Scientific and Technological Development) showed that LCF can also be a cost-effective way to produce spores of U.S. and Brazilian strains of Beauveria, Isaria, and Trichoderma fungi.In trials, the blastospores proved more effective than conidia generated by commercial production methods.
For example, blastospores from LCF cultures of Beauveria killed silverleaf whitefly nymphs 25 per cent faster than the conidia. Fewer blastospores were also required. Their studies also demonstrated, for the first time, that under appropriate LCF conditions, Trichoderma can form microsclerotia suitable for use as a seed coating or soil-incorporated granules to guard against plant diseases.
January 15, 2014 - Greg Stewart of OMAFRA reports on the 2014 growing year for corn in Ontario.
April of 2014 proved to be cool and wet and provided virtually no opportunity to plant corn. However, beginning May 1, things turned around and approximately 40 per cent of the corn acreage was planted by May 12th. Frequently, rainy weather moved across much of the western part of the province in the period May 13 to May 25 and the remaining 60 per cent of the acreage was mostly planted in the window from May 26 to June 3.
Total acreage planted in Ontario was 1,875,000 which was down about 15 per cent from 2013. Some of this reduction was market force driven and some caused by less than optimum planting windows. The delayed planting resulted in growers switching to shorter season hybrid or to soybeans. Generally rainfall and soil moisture was adequate to promote good emergence in both the early planted and the later planted corn.
Early season leaf injury to corn plants from herbicide or nitrogen (UAN) applications was particularly noticeable in 2014. This was due to thinner leaf cuticles as a result of more cooler, cloudier, high humidity conditions than normal in the May/June period.
The OMAFRA Soil Nitrate Survey conducted on June 10 resulted in soil nitrate levels that were lower than average. On the medium textured soils (loams and silt loams) that had not received fertilizer nitrogen or manure, and where the previous crop was not red clover or alfalfa, soil nitrate levels were below the long term trend. The average from these soils this year was 9.8 PPM nitrate, compared to an historical average of 11.0 PPM and compared to 12.2 PPM in 2012 (warm spring) and 9.5 PPM in 2011 (cool, wet spring).
June weather was conducive to extensive field work allowing for the completion of planting and rather unencumbered spraying and nitrogen applications. By July 1 the Ontario corn crop, on average, rated from good to very good.
Cool weather in July slowed crop development down at a critical time. During the last part of July most areas recorded CHU accumulation 15 per cent below normal and in some areas accumulation was almost 25 per cent below the 30 year average. On the positive side frequent rainfall and virtually no heat or drought stress resulted in very successful pollination and as a result kernel counts were quite high.With the combination of later planting and a cooler than average July it was clear by mid-August that the 2014 corn crop was significantly delayed and that grain filling was going to need to continue into September and beyond. Fortunately most areas escaped a killing frost until well into October, the main exception being extreme eastern Ontario where temperatures dipped into the -2 to -4 C range on September 19th.
The delayed grain filling trimmed what might have been record breaking yields, reduced test weight on the majority of the grain corn in the province, and significantly increased harvest moistures and drying costs. Stake holders were reminded that based on earlier research the feed value of lower test weigh corn remains quite competitive to typical #2 corn. However, the very high percentage of lower test weigh corn in some areas of the province will continue to represent marketing challenges.
The OMAFRA Grain Corn Vomitoxin Survey resulted in 9 per cent of the 202 samples testing 2.0 PPM or greater for DON. These results showed an increase in vomitoxin levels compared to the 2013 survey were only 2 per cent of the samples registered a DON level of more than 2.0 PPM but still indicated a relatively clean crop from an ear mould toxin perspective. In particular the samples with high DON concentrations in this year’s survey (>5.0 PPM) did appear to be closely associated with ears that had Western Bean Cutworm feeding damage that fostered the development of ear moulds and toxin development.
Northern Corn Leaf blight was evident in more areas and at higher infection levels than average, continuing a trend for some of the known resistance to be breaking down and to increase the risk posed to corn yields by this disease.The Ontario provincial corn yield for 2014 is 160.9 bu/acre. This will position 2014 as the second highest provincial corn yield of all time.
Jan. 6, 2015 - Three new products from Verdesian (PRIMO for soybeans, PRE-VAIL for forage crops and Accolade-L for wheat, canola and barley) recently received Canadian Food Inspection Agency (CFIA) approval and are now available to Canadian producers.
All three products contain a unique biological growth promoter to help get crops off to a good start early in the growing season. This biological growth promoter containing Azospirillum brasilense strains, derived from natural sources, is now available as a new viable option for producers.
PRIMO, a highly concentrated liquid inoculant, delivers a high-bacteria load of rhizobia to increase root mass, nodulation and, ultimately, the health of soybean plants. Its growth promotion abilities are a unique feature among available soybean inoculants, and results in increased levels of nitrogen fixation, leading to improved yields.
Accolade-L is the first biological growth promoter of its kind, containing Azospirillum brasilense strains, approved for wheat, canola and barley that can be applied directly to the seed as a seed treatment. The growth promoter in Accolade-L helps increase seedling vigor and improves root mass development as it fixes nitrogen in the root zone.
PRE-VAIL, a clay-based pre-inoculant for forages, can be applied directly to the seed, months in advance of planting, for added convenience. Its combination of nitrogen-fixing bacteria and the biological growth promoter help improve early forage growth and overall stands.
With each product containing Verdesian's exclusive Azospirillum brasilense strains, as well as having unique properties to get their plant species off to a good start, natural biological products from Verdesian help crops start out strong to improve yields down the road.
November 6, 2014 - In Ontario, over 80 per cent of nitrogen (N) is still applied to fields as urea through spinner spreaders and is incorporated with tillage equipment. However, Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) applied research coordinator, Ian McDonald, and others would like to see more N applied as a side dress in June.
“In the latter strategy, management decisions are made based on weather, crop performance, expected yield and so on,” he explains, “and the N application rate is targeted based on these conditions. When all the nitrogen is applied ‘up front,’ there is no way of making adjustments based on yield potential relative to current conditions.” Indeed, a later N rate decision can be very different than the N rate decision made before the crop has even been planted.
Many producers are reluctant to side dress, however. The reasons are many, including time and speed restraints, weather, herbicide application timing and a desire to avoid tramping emerged corn. “The reality is that side dressing, for those who are used to it, fits nicely in their system, lets them adjust N rates and doesn’t tramp much crop,” notes McDonald.
“We wanted to do a study to demonstrate that later applications of N could fit into farmers’ operations and give a number of important advantages.” For instance, UAN (urea mixed with ammonium nitrate) can be applied to emerged corn with large-capacity boom sprayers, which cover a lot of ground quickly and accurately without much crop damage.
In their study, McDonald and his colleague Greg Stewart (OMAFRA field crop corn specialist) also wanted to examine how much surface-applied UAN is susceptible to nitrogen loss through ammonia volatilization, compared to a more “protected” soil injection system. They also wished to see how surface applications of N in standing corn might cause leaf burn, which could in turn lead to yield loss. Grain Farmers of Ontario (GFO) provided support for the project, and technical assistance was provided by K. Janovicek, B. Rosser, W. Featherston, and J. Welch at the University of Guelph.
To investigate ammonia and yield loss potential of surface UAN application, the team compared the use of three-hole streamer nozzles (with or without Agrotain urease inhibitor) to UAN applied through injection below the soil surface with an Ag Systems coulter knife injector. There were two trials during the 2013 study seasons, one shortly after planting and another at conventional side-dress timing (V6 stage).
Nitrogen was applied at 100 lb N/ac so that yields would be responsive to N loss. McDonald and Stewart measured ammonia loss by dosimeter tube traps and final yields by weigh wagon. There were four trial locations each year.
Since ammonia volatilization is associated with surface applications of UAN, nozzles that concentrate UAN in a single stream are recommended. In this study, the team compared dribble band, flat fan, and three-hole streamer nozzles, using ammonia dosimeter tube traps on bare soil to measure volatilization. Each nozzle type was also applied with or without Agrotain urease inhibitor, with each treatment replicated four times within each application timing. To investigate the impact of precipitation on ammonia volatilization, one set of dosimeter traps was moved to “fresh” ground within plots following every rainfall while another set was not moved.
There were three locations where yield impact of leaf burn from post-emergent UAN applications was investigated. There were also three treatments including untreated, streamer nozzle applying N over the emerged corn and a directed application that delivered N under the corn canopy to the soil surface. All application treatments were conducted at the four, eight and 10 leaf stages and replicated three times for each timing at each location.
Yield and ammonia loss were assessed. Some of the yields from corn that received surface applications of UAN were no different than those that received it by soil injection, but some had significantly less yield. “The lower yields came from using streamer only (no Agrotain) at two locations in pre-plant application, and one sidedress location,” Stewart notes. “On the average, there was a yield loss of six bu/ac across all locations and timings with later N applications.” Streamer + Agrotain treatments were only significantly lower-yielding than injection at one side-dress location. Across all locations and application timings, ammonia readings were always highest for the streamer treatments and were followed by slight declines for the streamer + Agrotain treatments.
In the nozzle trials, the team found no clear difference in ammonia loss between application among the three nozzle types (fan, streamer, dribble). “This supports results from previous years, and suggests that using one nozzle over another doesn’t help mitigate ammonia volatilization,” McDonald notes. “However, when Agrotain was included with UAN, ammonia volatilization was consistently reduced across all nozzle types and most dates.”
As one would guess, precipitation decreases ammonia volatilization by washing the surface applied N into the soil. “However, it was very evident that when soil surfaces were dry, the risk of ammonia volatilization from surface-applied UAN was much lower than when the UAN was applied to wet soil surfaces prior to receiving sufficient precipitation to ‘wash’ the UAN into the soil and thus stop volatilization losses,” adds Stewart.
Applications up to the six leaf stage did not show yield-impacting levels of leaf burn, but those beyond the 10-leaf stage did show yield losses compared to injected side-dress or pre-plant N applications. McDonald says that between the six and 10-leaf stage, application impacts on corn yield are quite variable and thus should be avoided. However, they do offer a wider window with minimal yield loss expectations, should the weather cause an application delay. He says once the corn gets to the eight leaf stage, farmers should consider using drop pipes, Y drops, high boy injection systems and so on to get good placement of N for availability to the corn crop.
In terms of final recommendations to farmers, McDonald says based on the results of this study, farmers should surface-apply UAN or urea to dry soil, and should remember that precipitation of at least 15-20 mm is needed to incorporate surface-applied N into the soil to stop volatilization losses.
“In addition, consider that applications of N to emerged corn that is not washed into the soil may also cause reduced yields beyond straight leaf burn caused by leaf interception during application,” McDonald notes. “Regardless of the timing of N fertilizer to emerged corn, sufficient rainfall is needed to move the nutrient into the root zone to ensure it is available for plant uptake.”
McDonald says that since the study began, many farmers have been asking questions about N application into standing emerged corn. “Interest is growing, and it’s likely because of a few difficult spring planting seasons,” he explains. “Farmers recognize the importance of planting date on achieving optimal yield potential and are looking for ways to speed up the planting progress and address nutrient application and other management choices after planting.” McDonald and Stewart are writing up the final results of this project, and the complete final report will be available on www.gocorn.net
“We continue to look at this as part of other projects including a significant GFO and industry collaboration on increasing the understanding and adoption of precision agriculture in Ontario, with management zone development and variable rate applications of nutrients and plant population,” says McDonald.
An Ontario project is exploring the idea of mixing a later hybrid with a normal-season hybrid in a field to improve yields and drought-proof the crop. Photo courtesy of B. Rosser, University of Guelph.
Could mixing together two corn hybrids of different maturities boost your yields and help drought-proof your crop? That’s the intriguing question corn specialist Greg Stewart is exploring in a small project.
Seeding two corn hybrids together in a field has been examined in various studies over the years based on a variety of different ideas of how mixing might enhance yields. Stewart’s project is looking at three concepts.
One idea is that mixing could reduce the risk of pollination problems due to dry conditions. For good pollination, the timing of the pollen coming off the tassel needs to line up with the timing of the silks being receptive to pollen. “But in dry weather, sometimes that synchronization gets pulled apart – the pollen supply gets earlier and the silks get later. So the pollen sometimes dries up before the silks emerge,” explains Stewart, who is with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA).
“One approach to this problem is to mix a small percentage of a later hybrid in with your normal hybrid. If stress conditions occur, then that later hybrid might have pollen flying around when the majority of the field perhaps is still looking for a little more pollen.” Corn yields can be severely reduced if pollen shed and silking aren’t synchronized, so this approach could provide some valuable weather proofing when conditions are dry.
Another idea is that mixing in a small proportion of a longer-season hybrid might give a bit of a yield boost without too much added risk. “Most growers realize that full-season hybrids have a yield advantage but also some risk in terms of higher moistures or perhaps the crop not making it to maturity,” Stewart notes. “Rather than planting the entire field in that riskier, super, full-season hybrid, you could plant perhaps 20 or 25 per cent of the field to that hybrid. So you’re taking a bit of risk, hoping for some yield improvement, but it’s not as risky as planting the entire field in that long-season hybrid.”
A third rationale for mixing different hybrids is that it might provide out-crossing benefits. “Sometimes if the pollen from one hybrid lands on the silk of another hybrid, there can be an effect on kernel size or other kernel quality. If you could get the right combination of pollen from one hybrid and silks from another hybrid, then you could have a little yield improvement. But it’s a bit of a long shot to find some sort of magical pairing between hybrids,” Stewart says.
In this current project, Stewart is focusing primarily on the first two concepts: “I am dabbling with this idea of putting long-season hybrids in with normal-season hybrids for a given field,” he says. “I’m looking at the impacts on yield and harvest moisture, and I’m observing the pollen supply-and-demand scenario.”
Stewart started the project in 2013 with three Ontario sites. He was only able to establish one site in 2014 because of the ugly spring weather. The Water Resource Adaptation and Management Initiative of Farm & Food Care Ontario provided funding for the first year.
The project’s three treatments are a normal-season hybrid planted alone, a long-season hybrid planted alone, and a mixture of the two hybrids planted together. The later hybrid silks about five to eight days later than the normal one.
To blend the two hybrids in the mixed plots, the six-row planter used for plot seeding is set up so that rows 2 and 5 are seeded to the long-season hybrid, and rows 1, 3, 4 and 6 are seeded to the normal-season hybrid.
It hasn’t been possible to evaluate the pollen synchronization idea so far because dry weather stress didn’t occur in 2013 or 2014.
The preliminary results suggest there might be an advantage to the risk reduction idea under certain conditions. In 2013, at one of the three field sites (Bornholm, see table), the blend gave a significant yield boost. Although the moisture content for the blend was higher than for the normal-season hybrid, the yield boost with the blend was large enough to more than offset the extra drying costs. At the other two sites, there was no advantage to the blend.
Tips if you want to try it
If you’re thinking of experimenting with this concept, Stewart offers a few tips. “First, choose your normal top hybrid. Then choose a hybrid that is about a week longer, or is going to silk about a week later, or has a rating about 150 heat units higher than your main hybrid.”
Then choose what proportion of the field you’d like to have planted to the full-season hybrid. “I’ve been seeding about 25 per cent of the blended plots to the later hybrid, but I think it could be a lot less, perhaps five to 25 per cent of the field,” says Stewart.
Finally, decide how you want to mix the two hybrids together in the field. Although Stewart has been planting them in separate rows for ease of measurement in his project, he thinks there might be an advantage to physically mixing the two hybrids together before putting the seed in the hoppers. “We haven’t tested that, but I think if it turned out that you needed the pollen supply, then having the long-season hybrid completely dispersed throughout the field might give you a better advantage. The yield and the moisture content are not going to be affected by how you mix the hybrids.”
Oct. 29, 2014 - Reports from a new study, which for the first time will provide a comprehensive evaluation of the economic and societal benefits of neonicotinoid insecticides in North America, will be released today and over the next few months.
Conducted by independent agricultural economists and scientists with AgInfomatics, LLC, this research documents the value of neonicotinoids to agriculture as well as residential and urban landscapes, and the significant implications if these products were no longer available.
The study evaluated seed treatment, soil and foliar uses of neonicotinoid insecticides in the United States and Canada. Research included commodity crops such as corn, soybeans, wheat, cotton, sorghum and canola, specialty crops such as citrus, vegetables and grapes, plus turf, ornamental and landscape uses.
As the largest selling insecticide class in the world, some have questioned the value of neonicotinoids. This study was undertaken to provide reliable, objective evidence of the benefits these products bring to modern pest management systems.
Research results prove that neonicotinoids add billions of dollars to the economy, and benefit entire communities, not just individual growers.
In addition, research shows a loss of neonicotinoids would force growers to rely on a few, older classes of insecticides. More foliar sprays of broad-spectrum insecticides would be used in place of targeted seed or soil treatments.
Across selected commodity crops evaluated, the study found that each pound of neonicotinoid lost would be replaced by nearly five pounds of older insecticides. The consequences of this change would result in reduced crop yield and quality, disrupted pest management practices impacting beneficial insects including honey bees and, in some cases, catastrophic damage due to a lack of suitable alternatives to manage invasive pests.
Researchers surveyed over 22,000 growers, consumers and applicators in the United States and Canada, reviewed in-depth pesticide use information from leading data providers, and conducted a meta-analysis of yield performance involving thousands of observations. The team also conducted listening sessions in eight locations across North America to gain user insights and complement the quantitative data results.
AgInfomatics, LLC, is an agricultural consulting firm established in 1995 by professors from the University of Wisconsin-Madison and Washington State University. The research was jointly commissioned by Bayer, Syngenta and Valent, with additional support from Mitsui on the turf and ornamental studies.
The first three reports from the research to be released are:
- A qualitative perspective of the value of neonicotinoids from farmers and other agricultural professionals based on eight listening sessions
- A case study of neonicotinoid use in Florida citrus
- A case study of neonicotinoid use in mid-South cotton.
Subsequent reports will provide a more quantitative assessment of the costs and benefits associated with neonicotinoids across agricultural, municipal, ornamental and home settings.
All reports will be published online beginning October 29 at: www.GrowingMatters.org.
Sept. 4, 2014, Ontario – The 2014 growing season was the worst year in recent memory for poor root nodulation and nitrogen (N) fixation in soybeans. Cool, wet conditions cause numerous problems, including slow growth, low pod set, increased diseases, and lower yields. One significant problem that may be overlooked is that cool soil temperatures will delay or even inhibit nitrogen fixation.
Soybeans are a subtropical species. For optimal symbiotic activity the soil temperature should be between 25 C and 30 C. There were numerous first time fields where inoculant was applied, but nodulation did not occur. In other cases, nodulation did occur but not until early-August. Problems with poor nodulation happened across a wide geography and occurred with several different inoculant products, so it was not a product failure. In a few cases, even second time soybean fields failed to nodulate properly. Biological nitrogen fixation is essential for both first time fields and fields with a history of soybeans, because it converts gaseous nitrogen in the air (N2) to a form of nitrogen the plant can use.
How does nodulation occur?
Soybean plants secrete chemical signals (flavanoids) into the soil from the roots when the plant needs nitrogen. These signals are picked up by the rhizobia, which in return send a chemical signal back to the root. The signals sent back are called Nod factors and elicit nodulation in the plant. Within 10 to 14 days of colonization, a nodule will become visible. The return signal prepares the root for infection by the bacterium. Infection can only occur where root hairs are present. The nod factor causes root hairs to curl and pick up rhizobia and allows them to invade the root. As the bacterial cells divide, they form a small tumor like structure called a nodule.
Why was nodulation poor this year?
There are a number of factors that influence nodulation, nodual growth, and nitrogen fixation. These factors include too much or too little moisture, soil nitrate levels, soil pH, diseases, organic matter, soil temperature, and rhizobial quality.
This year, cool temperatures are to blame for poor nodulation. In some cases, soil conditions also turned dry immediately after seeding causing the bacteria to dry out and die before they could invade the roots.
Experiments conducted at McGill University by Zhang, Lynch, and Smith1 showed that between 17 C and 25 C, the onset of N2 fixation was delayed by 2.5 days for each degree decrease in temperature. Below 17 C, each degree delayed the onset of N2 fixation by 7.5 days. A root zone temperature of approximately 15 to 17 C seems to be the critical temperature for soybean nodulation and N fixation. By 49 days after inoculation, plants at temperatures between 17 C and 25 C were fixing some nitrogen, but plants at 15 C were not fixing any nitrogen. They also observed that a decrease of only 2 C, from 21 C to 19 C, made an important difference in the time to onset of N2 fixation, total N accumulation within the plant and overall growth.
Matthews and Hayes2 showed that nodulation can cease when temperatures fall to 10 C. Lynch and Smith3 showed that a root zone temperature of 15 C restricted both infection and nodule development and delayed the onset of N2 fixation by four to six weeks. Plants with a root zone temperature of 15 C had only fixed nine per cent of the nitrogen fixed by plants at 25 C six weeks after inoculation.
This helps us understand why in some cases soybeans did not nodulate until late-July or early-August this year. No-till fields, especially those with large amounts of crop residue, also suffered more from a lack of nodulation because these soils are generally cooler by a few degrees C.
Soil nitrate and N fixation
High nitrate levels also caused some problems. Nodule formation is inhibited by the presence of high nitrate levels in the soil. If the soybean plant picks up too much nitrogen early in the season, it will delay or prevent nodulation. The reduction of atmospheric N2 to ammonia is energetically expensive, and costs more photosynthate than simply taking up nitrate, so the plant will naturally consume nitrates before attempting to nodulate. This fundamental inability to develop and sustain N2 fixation in the presence of soil nitrates at greater than very small “starter” fertilizer rates is one of the reasons why nitrogen fertilization does not pay in soybeans. Applying nitrogen fertilizer simply reduces the amount of N2 fixed from the air.
What about next year?
Temperatures in Ontario in June and July are generally sufficient for proper nodulation, so under average conditions this problem will not be significant. In first time soybean fields, use two inoculant products such as a peat and a liquid at the high rate with good coverage. Some first time fields that used only one product or a pre-inoculant had complete nodulation failures in 2014. Using two products will help to increase the number of live bacteria available for nodulation. It is also essential to consider the bacterial viability with pesticide seed treatments. The only remedy to a nodulation failure is to apply N fertilizer at first flower or early pod set.
1) Zhang F, Lynch D. H, and Smith D.L. (1995) Impact of low root temperatures in soybean on nodulation and nitrogen fixation. Env. And Exp. Botany, Vol 35, no3 pp. 279-285.
2) Matthews D.J. and Hayes P. (1982) Effect of root zone temperature on early growth, nodulation and nitrogen fixation in soya beans. F. Agric. Sci 98, 371-376.
3) Lynch D.H. and Smith D. L. (1993) Soybean nodulation and N2 fixation as affected by period of exposure to a low root zone temperature. Physiol. Plant. 88, 212-220.
July 2, 2014 - The United States Department of Agriculture (USDA) says U.S. farmers planted the largest soybean crop ever this year, while a corn craze appears to have popped.
Demand for ethanol fuelled high corn prices, so farmers opted to grow it year after year, depleting their soil.
Many farmers indicated this year, however, that they would return to their corn-soybean crop rotation to replenish nitrogen in the soil and take advantage of the increased profitability of soybeans.
About a third of the U.S. soybean crop is exported to China where there's a large demand for soybeans to feed hogs, poultry, and dairy cows. (AP)
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