Rotating different herbicide modes of action and applying pre-emergence residual herbicides in Jim Call’s corn and soybeans are a couple ways the Madison, Minnesota, farmer fends off herbicide-resistant weeds. These days, though, keeping ahead of glyphosate-resistant weeds like waterhemp keeps Call busy. “I’ve been dealing with it for at least three years,” he says. Still, something’s missing. “Newer technology would help open up new weed-control avenues that I could use,” says Call. It’s coming. Three new herbicide-tolerant technologies – one that will be on tap in 2015 on a limited basis and a couple others soon likely to follow – will be available for farmers to use. Here’s a preview.
Federal regulators have approved the Enlist Weed Control System from Dow AgroSciences. The system includes tolerance to 2,4-D and glyphosate in corn and soybeans, and fop herbicides in corn. The herbicide’s new 2,4-D formulation, 2,4-D choline, has less potential for off-target movement than current formulations, say Dow officials. The new formulation will be included with glyphosate in the system’s herbicide component, Enlist Duo. Dow plans to market the system to select growers in 2015. Federal regulators initially approved the system in Illinois, Indiana, Iowa, Ohio, South Dakota, and Wisconsin. Regulators are also considering granting registration in Arkansas, Kansas, Louisiana, Minnesota, Mississippi, Missouri, Nebraska, North Dakota, Oklahoma, and Tennessee. Dow has also collaborated with MS Technologies, a West Point, Iowa, firm, to develop Enlist E3 soybeans. These soybeans will tolerate 2,4-D choline, glyphosate, and glufosinate. Federal approval was also granted to these soybeans.
Waiting in the wings is Monsanto’s Roundup Ready 2 Xtend System. The system’s Genuity Roundup Ready 2 Xtend soybeans will tolerate glyphosate and new formulations of dicamba. Monsanto’s herbicides for this system will include Roundup Xtend, a glyphosate-dicamba premix. Roundup XtendiMax is a stand-alone formulation. Monsanto officials say these dicamba components contain proprietary VaporGrip technology that reduces dicamba volatility when compared with existing dicamba formulations. BASF’s Engenia herbicide is another new low-volatility dicamba herbicide that can be used in the system, say BASF officials. Federal regulators have not yet approved the system. However, approval is expected later this year. Pending regulatory approval, a commercial launch for soybeans is planned for 2016, says John Combest, a Monsanto spokesperson.
The Balance Bean GT Soybean Performance System from Bayer CropScience and MS Technologies will be paired with a glyphosate and isoxaflutole-based herbicide with the HPPD inhibitor mode of action. Isoxaflutole is the active ingredient in Balance Flexx herbicide, currently used on corn. The system’s herbicide will be called Balance Bean. The system is not yet approved, but the firms expect federal approval mid-decade. Bayer and Syngenta are also working on soybean tolerance to isoxaflutole and mesotrione, another HPPD-inhibitor herbicide contained in the corn herbicide, Callisto. Bayer and Syngenta officials say approval is expected toward the end of this decade.
When applied according to label directions, all new products give excellent weed control. Still, you’ll need to think differently about weed management from now on. Consider the following factors.
Remember when your mom or dad used to nag you about doing your homework? Call’s agronomist played that role in the heady early days of the Roundup Ready system, when just two postemergence passes of glyphosate were needed in corn and soybeans. “Our agronomist complained about the Roundup monoculture for years, saying, ‘It will come back to bite you guys,’” says Call. It did. Soon, glyphosate-resistant weeds infested the Corn Belt. Resistance isn’t just limited to glyphosate, either. Even though the traits and formulations are new in new herbicide-tolerant systems, the herbicides aren’t. Waterhemp – the scourge of Corn Belt soybeans – already has biotypes that resist herbicides from six modes of action including synthetic auxins (2,4-D) and HPPD inhibitors (tembotrione, as in Laudis). The herbicides themselves didn’t spur resistance, but repeated use by farmers over time did. “I don’t think the new technologies will be the cure-all for weed resistance,” says Call. “We became overconfident with Roundup (Ready) and overused Roundup. With the new technologies and new chemicals, we will have to watch that again.” Now, he plans to mix up multiple herbicide modes of action and application times to keep weeds off balance.
Ever heard a fisherman telling an arm-extending “that fish was this big” whopper? It’s akin to a farmer bragging about spraying and killing 18-inch high water hemp. Waiting to spray weeds that tall in one post emergence shot may have worked in the days of Roundup Ready. It won’t with these new technologies. Labels for these products will likely zero in on post emergence applications when weed height is 4 inches or less. “Start thinking of spraying when water hemp is at the 2-inch height,” says Craig Lamoureux, a Monsanto technical development representative. “By the time you get the sprayer ready, it could grow to a 4-inch height on that same day.” Use a pre emergence residual herbicide. This adds multiple modes of action and helps reduce pressure on old and new post emergence herbicide-tolerant technologies. It doesn’t eliminate resistance potential, though, as any herbicide selects for resistance, says Aaron Hager, University of Illinois Extension weed specialist. “We control water hemp using pre emergence chemicals and again early in when it’s a couple inches tall (with post emergence herbicides),” says Call. “We are nuts about controlling it when it is small. You can control anything if you have a thick enough wallet. But with low-price (crops) situations, you just can’t spray $50 to $70 per acre worth of herbicides.” Cultural ways to nix weeds early include 15-inch rows. “Early canopy closure is a good weed control tool,” says Lamoureaux. Cover crops can also smother early emerging weeds. “The most vulnerable stage (for water hemp) is the seed stage,” says Hager.
Charlie Johnson, who farms with his brother, Allan, near Madison, South Dakota, has had portions of their farm’s organic fields damaged by glyphosate and Banvel (dicamba) drift for the last four years. That makes Johnson particularly leery of the new herbicide-tolerant technology. “There’s an assumption now that everyone has Roundup technology in their fields,” he says. “In the past 10 years, there’s been a tendency among applicators that ‘you take some of my drift, you take some of mine.’ They forget how sensitive non-GMO soybeans are to drift.”
Dicamba and 2,4-D have historically been prone to off-target movement via drift and/or volatilization. However, the firms manufacturing herbicides for the 2,4-D-tolerant and dicamba-tolerant systems say they have made good strides in reducing off-target movement potential. Dow officials say the Enlist Duo herbicide that contains 2,4-D choline has 87% and 96% reduction in volatility compared to existing 2,4-D amine and 2,4-D ester formulations, respectively. Meanwhile, Enlist Duo cuts drift potential 90% compared to older 2,4-D formulations when applied with low-drift potential nozzles, say Dow officials. That’s also the case with new dicamba-tolerant technology, say BASF and Monsanto officials. Both firms say their dicamba-tolerant forms are low in volatility. Flat-fan nozzles won’t cut it for these systems. A number of low-drift nozzles will be offered to give farmers and applicators choice, say Dow officials. Monsanto and BASF will also recommend low-drift nozzles on product labels. Follow label directions and use only approved formulations of these chemistires. This not only ensures optimal application but also reduces off-target liability. “If you go off-label with flat fans, you are 100% liable for that misapplication,” says John Cantwell, Monsanto technical development representative.
Besides using special low-drift nozzles stated on the label, you’ll need to clean out your spray tank and lines to avoid spray contamination between different chemistry types. “We recommend a triple rinse,” says Combest. Budget time to do it. “Cleanout will be more difficult on big sprayers,” says Call. “There can be a lot of spray in those 120-foot booms.” Without a doubt, it will be a challenge, adds Hager. “Applicators will have to allow for a thorough cleanout process. It doesn’t take that much dicamba to cause injury symptoms.”
In the case of BASF’s new dicamba formulation Engenia, boom height no more than 24 inches above the canopy is recommended. “Slow down,” says Mark Storr, BASF technical development representative. When speed increases, booms can bounce above that 24-inch threshold.
Storr says it’s best to spray when wind speed is between 3 and 15 mph. Spraying in still conditions is not recommended, as temperature inversions can move spray off target. Above 15 mph, wind can carry the chemical off target. Consider wind direction, too. If it’s blowing toward a vineyard, don’t spray. “You can use wind direction to your advantage, if it’s blowing away from a sensitive crop, “Storr says. Expect setbacks. “The distances will be defined by rate and wind speed,” he says.
This ensures enough water to produce large enough droplets to help reduce off-target movement potential. In Engenia’s case, 10 gallons per acre is the minimum. This helps ensure good coverage and produces large droplets not prone to drift, says Storr. Many are watching EPA approval of the Enlist Duo herbicide includes first-time-ever pesticide drift restrictions that include:
• A 30-foot in-field no-spray buffer zone around the application area.
• No pesticide application when the wind speed is over 15 mph.
• Only ground applications.
Requirements also include extensive surveying and reporting to EPA, grower education, and remediation plans. This doesn’t apply only to Enlist. Officials for the EPA intend to apply this approach for all existing and new herbicides used on herbicide-tolerant crops. The upshot is, this technology will diversify weed management and help forestall herbicide-resistant weeds. That said, herbicide-tolerant systems will also be closely scrutinized for off-target movement. After wrestling with four consecutive years of drift, Johnson is skeptical. “It’s like the basics of cattle farming, in that you don’t let your cows go on the other side of the fence,” he says. “It’s the same way with herbicides. You don’t want them to jump the fence.”
Oats bids in Western Canada are holding steady for the time being, but could be due for a setback given the weak U.S. corn market and declining nearby demand. “My bias is towards oats prices going down in relation to other commodities,” said Ryan McKnight of Linear Grain at Carman, Man. Demand from the horse sector was backing away, he said, with corn and other grains cheaper to feed than oats. Demand from U.S. millers was also slowing down, as oat stocks in Minneapolis and Duluth are building. Funds are also holding large long positions in the CBOT futures and oats could see a big move if they start to liquidate, “but it’s hard to predict when, or if, that will happen,” said McKnight. Over the past winter, logistics issues moving Canadian oats to the U.S. caused prices to rise. While the transportation situation is still not perfect, the oats are generally getting where they need to go for the time being.
Jarrod Firlotte of Emerson Milling, near Emerson, Man. just north of the U.S. border, said his company was still buying spot oats, but was comfortable with contracted supplies through February. There were some quality issues with this year’s smaller crop, he said, but those had only been a small portion of the samples submitted. BOT December corn settled at US$3.4825 per bushel on Monday, while December oats were two cents above that at US$3.505 per bushel. The strength of oats relative to corn is not a historically sustainable spread, as oats typically trade at a discount of as much as $2 relative to corn. Cash bids in Western Canada are currently topping out at as much as C$3.40 per bushel in Manitoba, according to Prairie Ag Hotwire data.
It’s midnight in the canola field and all is quiet, except for the distant chirping of crickets and the rumble and hiss of the sprayer. Equipment technology has evolved to where night spraying is no harder than day spraying, which can be handy when timing is crucial and acres are many. But does spraying at night provide effective weed control? A three-year study undertaken by the Farming Smarter research group based in Lethbridge sought to find the answer. Now wrapping up Year 3, researchers have bad news for early birds. The common practice of morning spraying for pre-seeding burn-down is less effective than either midnight or midday, with midday showing best results.
Initial results for in-crop spraying show midday herbicide applications have the highest efficacy in peas and canola, while midnight applications provided best control of grassy weeds. Information about the trials was a topic of discussion at the Farming Smarter field school, which ran June 24-26 in Lethbridge. “The advent of autosteer has sort of expanded the opportunity to spray at night time, and some guys are crazy enough to do it,” said director Ken Coles. “You do the outside round (first), you make sure you know where your potholes are, and it does give you an expanded window of operation.” However, most registered herbicides were tested for daytime application, so trials designed by Agriculture Canada research scientist Bob Blackshaw sprayed crop plots at dawn (4 to 5 a.m.) noon (12-1 p.m.) and midnight (12-1 a.m.)
Plots included Liberty Link and Roundup Ready canola, peas and wheat. Various types and rates of chemicals were tested, creating reams of data that will be crunched over the coming months. “When I started off in this endeavor, I really didn’t think, to be honest, that we would see the differences that we have,” said Coles. “I think it’s one of these opportunities that if we have a better understanding of which herbicides work under which conditions, we might be able to come up with a bit of a schedule that will maximize our efficacies.” Differences between the spray timings were more significant in early growth stages, but tended to level out before harvest, according to early data. Blacks haw said research results brought surprises but also assurances about night spraying. “Some of this research has shown that in some cases with some herbicides there’s not a large negative effect, so I think producers that still want to do that, especially if they get behind because of adverse weather conditions … it’s not an absolute no-no.” However, he said for some herbicides, spraying in the daytime provides better results. “I think that’s especially true for early in the year … when we have cooler conditions.” It has proven more difficult to analyze how herbicides with different modes of action respond to spray timing. Blackshaw said he thinks it plays a role, but more research is needed for definitive answers. However, temperature at time of spraying definitely makes a difference, Blackshaw told farmers at the field school.
He said daytime temperatures of at least 10 °C are needed for herbicides to be effective. “The crop needs to grow so it can metabolize the herbicide and break it down so it’s not injured, and the weed needs to grow so that the herbicide can actually do the job on it.” It means reasonably warm, sunny conditions. The more actively weeds are growing, the better the herbicide can kill them. Coles said temperatures generally reach their 24-hour lows in the early morning, when relative humidity is highest and dew is heaviest. That will affect chemical efficacy. Dew might help the chemical spread on the plant, and leaves may be more hydrated, but that doesn’t necessarily mean the plant is efficiently translocating the ingredients because it is not photosynthesizing. The Alberta Canola Producers Commission and the Alberta Barley Commission funded the night spraying research.
The new techniques could restore some of the properties lost in domesticated crops, Palmgren and colleagues contend in a review article published online December 16 in Trends in Plant Science. “We estimate that all crops would benefit from rewilding,” he says. Crops could be modified to draw nutrients from the soil more efficiently and be made more resilient against drought, cold, diseases and pests. Such an approach, called reverse breeding, is not a new concept, says Mark Sorrells, a plant breeder and geneticist at Cornell University. “What they’re calling ‘back to nature’ practices are practices that have been used by farmers in varying degrees for many years,” he says. “It is true that in the process of domestication and breeding modern varieties, genetic variation for some characteristics has been lost, and that is why breeders routinely go back to wild relatives to find that genetic variation.”
And the challenge that Palmgren and coauthors raise identifying mutations found in domesticated crops but not in their wild cousins is not the biggest technical hurdle, Sorrells says. “Once you find these traits, mapping them and transferring them to modern varieties is what the formidable task is.” By 2050, the world’s population is predicted to surpass 9 billion. One strategy to meet food demands is to give crops new genes with benefits their wild relatives never had. These transgenic crops, also known as genetically modified organisms, are viewed with distrust by many people. Traditionally, reverse breeding has been carried out by crossing crops with wild versions of the plant that have the desired trait. But the resulting hybrid may also end up with other qualities that breeders had intentionally gotten rid of. “Wild plants are seldom tasty, nutritious, and easy to harvest,” says Palmgren. The process of perfecting the hybrid plant is time-consuming and difficult to control. Today’s biotechnology can surgically repair the deficiencies in crops, says Palmgren. One method, called cisgenesis, inserts a gene from a wild relative into a crop. In May, researchers from Korea and the Netherlands reported using cisgenesis to transfer genes from wild potatoes into domesticated relatives, making the crops more resilient to blight from the fungus Phytophthora infestans.
Researchers in Switzerland and Germany have also used cisgenesis to insert a single gene into Gala apples to make them less vulnerable to apple scab, a condition caused by the fungus Venturia inaequalis. To make the apple as hardy as its wild cousins, however, this task will require the addition of multiple genes. With cisgenesis, “you don’t need to go through extensive crossing to induce the trait, so it basically makes the whole process faster,” says Vladimir Nekrasov, a plant biologist at the Sainsbury Laboratory in Norwich, England. Another method, precision mutagenesis, is even more exacting. Researchers change the order of DNA building blocks to return a gene to its wild form. So far the method has been tested on several plants, including tobacco, sorghum and rice. Palmgren and coauthors discuss only techniques that edit one or a few genes and are not effective for improving traits controlled by many genes, says Sorrells. Another technique, genomic selection, allows researchers to survey a sample of genetic variants in a crop’s genome to predict which variations are most likely to result in higher yields or resilience against disease. Genomic selection allows researchers to pick out individuals that have more of the genes that contribute to the trait in question.
“These authors didn’t even mention that, and it’s probably one of the most exciting technologies currently being researched in plant breeding,” Sorrells notes. Clay Sneller, a plant breeder and geneticist at Ohio State University in Columbus, also expressed skepticism. “I find their whole premise to be rather flawed,” he said. “They appear to think that during breeding we have accumulated negative mutations, and if we got rid of those mutations then the crop would be better. They reviewed no evidence that this occurs on a wide scale in genes that truly matter.”
The R3 stage is when there are pods developing on the lower nodes (there still will be flowers on the upper nodes as the stages in soybeans overlap). As a general rule, most fungicides are recommended at the R3 stage of growth. The question is, are they worth it? This is a difficult question to answer and will depend on many factors. Let’s take a look at a few of those factors:
Most farmers apply a fungicide to control diseases. Fungicides do an excellent job of this as long as the disease is on the label. It is important to remember that fungicides will not control SDS, Phytophthora, or any bacterial diseases, and there are only a few fungicides that will help with white mold.
This is probably a touchy subject and many people have their idea of the proper product choice. In my experience the strobilurin class of fungicides has provided the most consistent yield responses (Quadris, Approach, Headline, and premixes with these active ingredients). This same class of fungicides will keep your soybeans greener for a longer period of time increasing the chance for larger soybean seed size and therefore higher yield potential. It may also make soybeans tougher to cut in the fall.
Several studies have shown that the R3 stage provides higher, more consistent yield responses than the R1 (beginning flower) stage. There are few studies (or none) comparing fungicide applications at later stages. It would be interesting to know if applications closer to R4 or R5 could increase yields greater than the R3 stage.
Continuous wet weather will increase the chances for disease and the possibility of a response. We don’t know what the weather will be like so this is difficult to predict. If you think the prospects are good for a good yield, then you may want to protect your investment with a fungicide.
If you have a variety that is more susceptible to diseases such as Septoria brown spot, Frogeye, or Cercospora, then a fungicide may increase the likelihood of response.
Due to the wet weather this year there may be more fields that have a soybean/soybean rotation. In these situations disease pressure will be higher and have a greater probability of response. The average yield response of University studies is around 2 Bu./A. If you decide to use a fungicide be sure to leave a check strip and note the stage of the soybeans to determine if it was worth it. Some farmers may decide to throw in an insecticide to go along with the fungicide and the results have been variable. The only feeders I have noticed this year are Japanese beetles and a few bean leaf beetles.
A southern Manitoba corn agronomist says most corn farmers in the province can expect to see average yields this season. “Normally harvest would begin in late September but I would be surprised if that happened. I think it will be the first or second week of October,” said Morgan Cott of the Manitoba Corn Growers Association at Carman, adding frost could push that back even more. She cited wet weather as the reason behind the delay. Despite the heavy amount of rain that struck the province in late August and September, Cott doesn’t think that damaged the crop. “Corn can tolerate a lot, especially since the ground was so dry; there’s a lot of room for that water to go,” she said, noting the deep-rooted soil would allow the water to move quickly. Manitoba corn is generally two weeks behind where it normally is at this time of year, but was still showing good development.
“The cobs were filling very nicely, thick cobs. They were filling right to the tip in most cases which is excellent.” Overall, Cott said it looks like a good year for corn, considering the late start to the season. “It’s all we could ask for with the type of spring we had,” said Cott. Estimates for this year’s crop in the province sit at 275,000 acres of grain corn and 85,000 for silage corn, she said. While some frost has been reported in some corn crops, Cott isn’t sure whether it ended up doing damage. “Who knows, we’ll have to wait and see,” she said. While temperatures of -1 C have been known to damage corn crops, Cott said it depends on other conditions at the time of the freeze, such as cloud cover and wind. From now until harvest, temperatures in the mid-teens (C) would be ideal. “Ten-degree days don’t really help a lot.”
Air turbulence and wind created by high sprayer speeds can destroy spray patterns and adversely affect spray coverage. Farmers seed at 4.5 m.p.h. or less, even though they can go faster. They combine at five m.p.h., even though they can go faster. That’s because they know that prudent machine speed puts more money in the bank. So why do many producers run their high clearance sprayers at top speed, regardless of how much product hits the target? asked Tom Wolf, a crop spray researcher.
“Farmers can get down out of the cab to dig up a few seed rows and actually see where the seed and fertilizer are being placed. With that knowledge, they can determine their maximum seeding speed,” he said. As well, he said the Canola Council of Canada and drill manufacturers have done an excellent extension job on the Prairies when it comes to explaining the importance of prudent ground speed. “It’s the same thing on the combine,” he said. “You can look at your monitors and look in the bin and then figure out if you can go faster or if you should slow down. But with the sprayer, it’s a different story. It’s difficult to get out of the cab and do any kind of accurate assessment of how much crop protection product is actually landing on target.”
The reality is that spraying is often a matter of time rather than quality. As well, many farmers admit they just hate spraying and want to get it done as soon as possible. Those issues are compounded by the fact that manufacturers have made huge improvements in sprayer suspension systems, allowing operators to run at 25 m.p.h. without de-stroying their machines. But do those speeds destroy the quality of the spray job? “Manufacturers have invested tremendously in chassis improvements, strength, power, liquid capacity, hydraulics, electronics, cabs and everything else, but there is absolutely no relationship between these improvements and a farmer’s ability to kill the pests,” Wolf said. “All they’ve accomplished is increased capacity and increased speed and create more problems for nozzles. The fundamental problems we’ve always had are not being resolved. In general, spray deposition is getting worse, not better, and it’s largely because of travel speed.” Wolf said problems caused by high-speed spraying include poor canopy penetration, more dust from faster tire rotation and higher boom heights, which contribute to poor spray targeting and spray drift. Given the state of today’s nozzle technology, the only way to address those problems is to slow down.
Wolf thinks sprayers are now large enough and fast enough to create significant air turbulence of their own. “High clearance sprayers have aerodynamic properties that affect spray deposition, just like the aerodynamic properties of spray planes. Things like wing shape and boom shape affect deposition,” he said. “We may have to start looking at the aerodynamics of ground sprayers in the same way we deal with aircraft. Aerodynamics was never a factor when we ran our ground sprayers at eight m.p.h., but it’s a whole new ballgame when you double or triple that speed. “Let’s say you’re spraying at 20 m.p.h., which is too fast by the way, and you’re facing a 10 m.p.h. head wind. You are generating a ton of air movement around that tractor unit and boom as one air flow hits the other air flow. That has a huge impact on the spray pattern and its ability to penetrate the canopy. But do we know what that impact is? No.” Another problem is caused by the traditional sprayer’s reliance on pressure to control liquid flow.
Pressure in the system might be 50 to 60 pounds per sq. inch when a farmer sprays at 20 m.p.h., which is where most modern low-drift nozzles work well. Pressure drops by 25 percent when the operator slows to 10 m.p.h. for rough ground, a hill or a turn because of the square root relationship between pressure and flow rate. As a result, nozzle patterns collapse and sprays become too coarse. The square root relationship means that if operators want a two-fold range of travel speed, from 10 to 20 m.p.h., they will also need a four-fold range of pressures, from 30 to 120 p.s.i. “We’re pushing the envelope with this example because most pumps won’t do 120 p.s.i. Most nozzles start to give a drift-prone spray at that pressure. And when you drop to 30 p.s.i., you get extremely coarse droplets,” Wolf said. “Most operators want that travel range of 10 to 20 m.p.h., but that range will give you a dramatically different range of spray qualities. And of course that has a major impact on the quality of the spray application in terms of drift, efficacy, canopy penetration and uniform coverage.” He said a silver lining to this story is that air induction technology has expanded the speed range at which today’s farmers typically spray. The benefit is that air induction nozzles do a better job at higher pressures than conventional nozzles, and they do it without too much drift. “Air induction technology has essentially given us a 1.8:1 ratio for our travel speed.
If your maximum travel speed is 18 m.p.h., then your lowest possible spraying speed is 10 m.p.h.,” he said. “But that’s not enough of a range for some. If you want a wider range of travel speed, then you have the Pulse Width Modulation systems. There’s the SharpShooter from Capstan and AIM Command from Case. We also have VariTarget variable rate nozzles with flexible orifices that open up just a little to allow more flow under higher pressure. “A new technology from Pentair (Hypro) that will be ready for introduction in 2015 or 2016 is a nozzle body that will hold a number of nozzles and turn them on or off according to the requirement.” Wolf said that despite these innovations, there is a lack of investment in nozzle research and development, which is why nozzles can’t keep pace with sprayer speeds. “The major sprayer manufacturers are in a race,” he said. “They’re all telling farmers, ‘hey, we can go faster than the other guys.’ That’s not the message they should be sending. They should be talking about quality of the spray application. “They’re able to duck that question because they don’t make nozzles. They leave that to someone else. And this is an interesting point. Most of the world’s major nozzle manufacturers are small family-owned businesses.
“That includes Agrotop (Greenleaf), Billericay Farm Services (Air Bubble Jet) and Wilger (ComboJet). T-Jet is the world’s biggest nozzle manufacturer, and I believe they’re still family owned.” Wolf said some of these companies have research and development budgets in the tens of thousands of dollars rather than tens of millions. “Given the size of these companies, I’d have to say that we get tremendous value when we spend $10 to buy a nozzle,” Wolf said. “I’ve been in some of these plants and watched them flow test every single nozzle by hand. That’s probably millions of nozzles in a year flow tested manually.” Borrowed genes raise hopes for fixing “slow and confused” plant enzyme Giving plants better chemistry for photosynthesis might one day lead to higher crop yields.
Coaxing bacterial genes to replace a notorious slowpoke of an enzyme in tobacco plants could be a step toward raising yields in food crops. Biologists have grumbled for decades about the clunky pace and wasteful mistakes of the enzyme nicknamed Rubisco (for D-ribulose-1, 5-bisphosphate carboxylase/oxygenase). A version of the enzyme orchestrates a key step in capturing carbon dioxide from the air for photosynthetic organisms from pond scum to redwoods. A large group of green plants, including soybeans, rice and wheat, has some of the least efficient Rubisco of all, ultimately limiting their productivity.
A way to rev up Rubisco may be a step nearer, thanks to gene replacement engineered by researchers at Cornell University and Rothamsted Research in Harpenden, England. Genes for a peppier Rubisco, borrowed from a cyanobacterium, created working enzymes in laboratory tobacco, the researchers report September 17 in Nature. Tobacco served as a botanical lab rat, but researchers hope what they are learning will someday make food plants more efficient.
More work needs to be done before researchers can make plants thrive with borrowed Rubisco genes, says coauthor Maureen Hanson, a molecular geneticist at Cornell. Still, she’s pleased with demonstrating that the transplanted genes work. “If you can’t get this to work,” she says, “you have to give up on the whole project.” This work looks “highly significant,” says Dean Price, whose lab at Australian National University in Canberra also explores ways to boost photosynthesis. Putting another species’ Rubisco genes into a plant isn’t new, but this time, researchers persuaded genes from cyanobacteria to make useful quantities of the enzyme.
If researchers can push plants such as soybeans or wheat to photosynthesize as efficiently as cyanobacteria do, crop yields might jump 36 to 60 percent, says Stephen Long of the University of Illinois at Urbana-Champaign. Trends suggest the world will need to double supplies of rice, wheat and soy by 2050 to feed the booming population, he says. The Rubisco enzyme is “slow and confused,” says plant biochemist Spencer Whitney, also at Australian National University. It can capture either carbon dioxide for photosynthesis, or oxygen, which short-circuits the usual energy capture and creates compounds the cell has to clean up. Rubisco’s early forms probably arose more than 3 billion years ago when CO2 dominated Earth’s atmosphere. But in today’s oxygen-rich atmosphere, it easily grabs wasteful O2 instead. Cyanobacteria minimize such waste by creating their own CO2 world. They encase their Rubisco in very tiny compartments where CO2 concentrates. There, with minimal oxygen temptation, the risk of mistakes is low. So cyanobacteria can use Rubisco forms that aren’t particularly discriminating but churn out their products fast.
Getting Rubisco genes to work in a new species poses quirky challenges. For instance, the eight large subunits of the Rubisco enzyme are normally encoded by genes in the chloroplast, but genes for the enzyme’s eight small subunits lie in the cell nucleus. Molecular biologist Myat Lin in Hanson’s lab coped by putting the cyanobacterial genes for both kinds of subunits plus some helpers into the tobacco chloroplasts. Chloroplasts have so many copies of some genes, around 2,500 instead of typically fewer than 10 in the cell nucleus, that cells produce chloroplast proteins in great abundance. The transfer worked well enough for cyanobacterial Rubisco to sustain photosynthesis on its own in the tobacco plants. And the transferred version captured more carbon per unit of enzyme than the plants’ usual Rubisco. However, the modified tobacco plants don’t have genes for CO2-concentrating compartments. Even when the researchers kept the plants in chambers with 22 times the CO2 of normal air, the tobacco plants still didn’t grow fast. For tobacco to take advantage of its new enzyme, researchers hope to add compartments, Hanson says. There are certainly other strategies for upgrading Rubisco, notes Howard Griffiths of the University of Cambridge. His lab is trying to cajole a plant version of the enzyme with superior discrimination for CO2 over O2 to function in loose aggregations that might provide some of the benefits of compartments.
The pigweed family of weeds is a late-season stalker of soybeans. It often survives your best early-control efforts and ends up towering over soybean fields in August and September. This infamous weed family includes common water hemp, Palmer amaranth, and redroot and smooth pigweed.
Compounding pigweed control is the fact that your best herbicide programs are failing in some places due to herbicide-resistant weeds. Some states see resistance to three or four herbicide classifications, including glyphosate, PPO inhibitors, and ALS inhibitors. All is not lost, though, says Kevin Bradley, University of Missouri Extension weed scientist. For several years, he’s been encouraging growers in his state to use a multiprong approach, focusing on the pigweeds’ most vulnerable traits that include the following.
At first glance, this would not appear to be a soft underbelly since single pigweed plants can produce 300,000 seeds or more. “They are relatively short-lived in the soil,” Bradley says. Tests have shown that over 50% of water hemp seeds remain viable after one year. After four or five years, though, only about 10% of the initial population will be capable of emergence. That’s low compared to many weeds. “Just tell yourself you are not going to allow any seed to get on the ground, from any plants,” he says. “If you do that for a few years, you’ll have greatly diminished the seed load in a field.” Some Southern farmers, who have battled herbicide-resistant Palmer amaranth longer than Midwest farmers, have reverted to hand-hoeing problem fields to stop seed production. If a pigweed plant escapes their best efforts, they will cut and carry it to a burn pile before it can go through the combine.
If you can use judicious tillage to bury pigweed seeds 6 inches deep or more, they won’t emerge. “By using the right combination of techniques, you can control pigweeds in a no-till system,” says Bradley. “If you have a really nasty field of resistant pigweeds, then one way of making a lot of progress in a short period of time is to use deep-tillage one time to bury the seed. Then you can begin managing that field much more judiciously in the future.” In one test, minimum-till and no-till resulted in pigweed plant density of 6 to 10 plants per square meter at the end of the soybean season. Deep-tillage reduced the weed density to almost zero, Bradley says.
While technically not pigweed weaknesses, these practices can give you advantages. Narrow rows, for instance, will normally result in less weed plant density of all weeds. Row spacings of 7.5 inches and 15 inches often provide similar weed control, and both are better than 30 inches. Quicker canopy and shade are the reasons. “We also have done tests on seeding rates, and as you reduce the rate on soybeans, you have a greater risk of weeds coming through,” says Bradley. He tested a 130,000-soybean seeding rate per acre compared with 160,000, 190,000, and 220,000. Every time the seeding rate rose, the late-season weed density went down. Cover crops can also curb weeds, Bradley says. In his tests, a cereal rye cover crop dramatically reduced pigweed emergence.
“Multiple modes of herbicide action will be my advice for the foreseeable future,” Bradley says. “There are several herbicide programs that can work to control pigweeds. But you need multiple modes of action, rather than just a single shot, to prevent the development of resistance to one class.” His general recommendations on this include:
Monday (Sept. 15) marks the full coverage crop insurance seeding deadline for winter wheat in Manitoba and Saskatchewan, with Alberta farmers having until the 20th or 30th of the month, depending on their location. A late harvest this year, however, has prevented some farmers from getting the crop seeded in time. “Unfortunately we’re seeing a lot more canola sitting in the swath, and since canola is our preferred stubble we’re not doing exceptionally well,” said Jake Davidson, executive director of Winter Cereals Canada at Minnedosa, Man. He estimated acreage planted this fall could be similar to last year, adding “last year was a low year anyway, so it might not be that hard to match it.” Last fall, farmers in Manitoba, Saskatchewan and Alberta seeded 1.13 million acres of winter wheat, down from 1.16 million the year prior, according to Statistics Canada. Manitoba farmers planted 435,000 acres, with 500,000 acres in Saskatchewan and 195,000 in Alberta last fall.
Though some farmers may miss the deadlines for seeding to get full crop insurance coverage, they may still seed the crop if conditions look good. They will also be able to get some reduced insurance coverage if they plant after the deadlines. “I’ve had people seed after Oct. 1 and come up with a crop,” said Davidson. “It just depends on the experience the person has, the weather conditions and how brave they are.” Some producers may even experiment and seed into dormancy and wait for it to come up in the spring. “A lot of people who grow winter wheat, they’ll put some in just to see what happens,” Davidson added. There has been good demand for seed this year, he said, adding there must have been a place for it to go. Farmers who aren’t able to plant on canola stubble are likely seeding winter wheat into their summerfallow or chemfallow acres, he added. So far, conditions for the crops that have been seeded are good, as soil moisture levels are favourable in many areas. “There are some crops that really have come along well where guys planted it into chemfallow and stuff like that,” said Davidson. “What got planted is growing very nicely; it’s just a matter of whether it gets warm again and how moist it is.”
There are more products available to farmers than there is good information, say the results of a two-year Canola Council of Canada study. Trials that tested several potentially yield boosting products and practices have found that tried and true best management practices win out more often than they lose. “It really comes down to buyer beware and encouraging growers to again look at good quality data when they’re making their purchasing decisions,” Clint Jurke of the council told a recent canola industry meeting in Saskatoon.
“I know that they’re often looking for ways of adding additional yield and adding additional profitability to their farming system, but unless they have good quality information like this, sometimes that does become a difficult decision to make.” The canola council collected data from trial sites in Saskatchewan and Alberta in 2013 and 2014. Co-operators tested a higher nitrogen application, a higher seeding rate of 150 seeds per sq. meter and boron applications at the four to six leaf stage and at flowering.
They also tested two seed primers, a “biostimulant” and a micronutrient. The results that Jurke presented won’t surprise growers: increasing the seeding rate results in greater emergence and a reduction in nitrogen shows itself in lower yields. Of the other treatments, nothing outperformed the best management practices that the canola council already recommends. Laryssa Grenkow, research manager for the Western Applied Research Corp., said she saw the same results at plots near Scott, Sask., although she noted it was “a relatively good growing season.” Trials in poorer conditions might have different results, she added. “Any of the additional products that we added really didn’t seem to affect any of the parameters that we measured, but there are some things that are tried and true,” she said. “Even your recommended seeding rate and in some circumstances maybe using a little higher rates of nitrogen, those are the types of things (where) I think that farmers are going to get the biggest bang for their buck. It’s when you start cutting corners and not using those recommended practices that you’re going to start losing yield.” Jurke said the trials underscore the value of nitrogen and soil testing.
Grenkow agreed. The Scott site, which yielded more than 50 bushels per acre in its plots, had low residual nitrogen on the trial site. “The best management practices that were being followed for fertility in these trials was to do a soil test and to base your nitrogen fertility on the basis of that test,” said Jurke. “What those tests were recommending was actually showing that it was a good way to try maximizing your yield.… We do want to continue encouraging growers to use soil tests as an effective way to target what their upper yield potential could be.” Loosened restrictions on fertilizer registrations have resulted in many new products on the marketplace.
“If you’re going to put the money out there, you have the right to know exactly what you’re paying for. I’d ask how it works, when it works, when it doesn’t work.… Even something like nitrogen fertilizer, you won’t get a response under certain circumstances,” she said. “It’s important to ask all kinds of questions and ask them when and where you’ll see a response. It’s very unlikely you’ll see a response every year.” Grenkow said farmers need to be diligent and do their homework. “If it is a new product and you’re pretty skeptical about it, the best thing to do is try it in a small area of the farm and always leave check strips and assess it and give it a few years and test it out on different fields,” she said. “That’ll probably give you a good idea of how it works for your particular farm, anyway.”
With an overload of fertilizer, soil microbes on farms may belch unexpectedly high levels of nitrous oxide, a greenhouse gas with 300 times as much heat-trapping power as carbon dioxide. The finding may help explain why agricultural nitrous oxide emissions are much higher than some scientists had predicted and could give clues for how to curb farm pollution. Soil microbes have long been known to convert nitrogen-rich crop fertilizers, including manure and synthetic fertilizers, into nitrous oxide. After more than 1,000 field experiments, climate scientists calculated in the mid-2000s that the dirt dwellers spew about one kilogram of the greenhouse gas for every 100 kilograms of fertilizer, or roughly 1 percent. Researchers generally thought that emissions would scale up linearly: doubling fertilizer would double the emissions of gas.
But the predictions didn’t match up with real-world numbers. Estimating regional and global fluxes of atmospheric nitrous oxide levels a few years ago, researchers pegged the microbial conversion of fertilizer to gas at somewhere between 1.75 and 5 percent. Either the initial calculations were off or there were unknown sources of nitrous oxide, says biogeochemist Phil Robertson of Michigan State University in East Lansing. The latter was unlikely, he adds.
From cornfield experiments in Michigan in 2005, Robertson and colleagues found that the relationship between the amount of fertilizer and production of greenhouse gas is not always linear. When farmers apply larger amounts of fertilizer than initially tested, the relationship appears exponential — applying 200 kilograms of fertilizer could result in four kilograms of gas, for instance. Most of the original field experiments, he says, didn’t look at microbial gas conversion with excess fertilizer, far more than crops need. In such situations, the crops take up as much nitrogen as they can, and the rest goes to soil microbes, Robertson says. “They effectively go to town on that nitrogen,” he says.
To see if the finding held up on a global scale, Robertson and colleagues reanalyzed more than 200 experiments, each examining nitrous oxide emissions of multiple fertilizer levels, across 84 locations worldwide. The results confirm that excess fertilizer can exponentially boost the emissions of microbes, the team reports June 9 in the Proceedings of the National Academy of Sciences. From this finding, Robertson infers that some farmers are using far more fertilizer than they need to, yielding more nitrous oxide than scientists had expected. The good news is that the study provides a clear path to lower nitrous oxide emissions, says soil scientist Timothy Griffis of the University of Minnesota in St. Paul. There are many easy methods for assessing how much nitrogen-based fertilizer is right for a crop field, so addressing overuse could be simple, he says. But the exponential relationship between fertilizer and gas still doesn’t entirely account for the emission discrepancy, says soil scientist Rod Venterea of the U.S. Department of Agriculture in St. Paul. There must be other factors upping the nitrous oxide in the atmosphere, he says, including unknown emissions from nitrogen fertilizer after it leaves farms via streams and erosion.
Extreme cold and snow cover in many parts of the country have growers guessing about the weather’s impact on pest pressures in the upcoming planting and growing season. Researchers say this winter’s weather could have some impact on pest populations, but many pests are just lying in wait.
“We see pest problems every year, regardless of conditions,” reports Paula Davis, senior manager for insect and disease traits at DuPont Pioneer. “This year it is a question of survival for crop pests. Some stinkbug species will not survive in extreme cold, and bean leaf beetles get knocked back when winter temperatures fall below 14°F for sustained periods of time. However, most soil insects are buffered by the soil, crop residue, and snow.”
Migrating insects are one category that may give growers a break in 2014. Freezing temperatures reached far enough south to potentially reduce the populations of some insects that move north during the growing season. For example, cold temperatures in the Deep South could knock out pests that move up into southern Missouri fields. “Most years, damage from early-season pests depends on how quickly the soil warms up,” Davis says. “Deep frost in the ground, cool springs, reduced tillage, and high residue result in cooler soil temperatures, which delays soil warmup, planting, and emergence. These conditions make plants more susceptible to insects.”
Davis suggests that growers scout their fields after planting to see how well their seed treatments are working. She advises growers to watch for various species of wireworms, grubs, and migratory pests — such as black cutworms — that won’t be affected by this winter’s cold temperatures. William Dolezal, DuPont Pioneer research fellow, says the cold winter won’t have a big impact on disease organisms, but a cold spring will. “Many of the pathogens that cause plant diseases are under a good blanket of snow cover and crop debris,” Dolezal says. “Disease organisms adapt to cold temperatures. As a result, the potential for plant diseases is present every spring. The key is to know what you have around you, and what you have on your farm.” With that operation-specific knowledge, growers can select hybrids with the right disease-resistance packages, and support their choices by adding the protection of fungicide seed treatments.
Dolezal recommends rotating with nonhost crops to break disease cycles. He also asserts that the best defense is to get corn and soybeans up and out of the ground quickly. “Planting too early gives the advantage to soil organisms,” he says. “Good weather at planting sets up good emergence, so growers should plant when the soil is warming and the weather outlook is good. This hastens faster early growth, moving plants away from the soil surface and debris that harbors many foliar pathogens.” Dolezal also advises growers to scout early so there is still time for foliar fungicide applications to address some disease problems, and to plan for disease-resistance packages in their seed selection for next year. During scouting, growers should look for seedling blight, gray leaf spot, leaf blight, and Goss’s bacterial wilt.
Canada’s mustard crop is seen to be in a good state right now as harvesting begins in some areas of the country. “I think harvest has started in the southwest part of Saskatchewan. That’s the earliest start because they were the first to get in the fields,” said Walter Dyck of Olds Products at Lethbridge, Alta. “And I know there where some timely rains that did hit in that period, in the last month, so I think that mustard crops overall are looking pretty good.” However, some mustard crops were impacted by heavy storms that passed over the growing regions, according to Dyck. “There were some storms that went through early August that might have had an effect,” he said. “But up until that point, mustard really hasn’t been affected too much with hail, not anything too much worse than previous years.” Other than some hail damage, he said, mustard crops haven’t had any other significant production issues. “The mustard usually escapes a lot of the insect threats that come about, it’s just the flavour of the mustard,” said Dyck. “But I haven’t heard anything that has caused any concern as far as needing spray or anything like that. I think some insects have been spotted in crops but I think in most cases it hasn’t been close to that threshold.”
Mustard prices are currently at a good place, he added, and “holding up really quite well given what’s going on in other grain and oilseed markets.” Brown mustard is now running around 30 to 33 cents a pound, while yellow mustard is closer to 36 cents/lb., he said. “It’s really holding up quite well from where prices were a year ago, they haven’t really come off that much,” he said. “And I think the main thing there is low inventory, and possibly some higher demand from Europe is always a possibility, but I’m not too sure what’s going to develop there at this point.” Southern and central Alberta will be next to start harvesting mustard, Dyck said, and the rest of Saskatchewan will probably begin in the next week or two. “Things are really coming along quite well this year, yields are looking above long-term averages for sure and last year was a really good year for average mustard yields,” he said. “And this year I don’t think it’ll get that high on average, but it’ll be pretty close, and I think a lot of farmers will be somewhat surprised with their yields.”
Compared with rows of maize, tufts of switchgrass grown for biofuel have hidden perks, a new study finds. The benefits over maize include increased biodiversity, removal of more greenhouse gases from the atmosphere and boosted pest control. The U.S. government encourages production of bioenergy crops, and maize, or corn, is the most commonly grown. But farmers might consider switchgrass or other prairie grasses instead if they knew of the crops’ strengths, says lead author Douglas Landis, an ecologist at Michigan State University in East Lansing.
Landis wanted to evaluate the benefits of growing bioenergy crops on marginal lands, sections of farmland that are suboptimal for growing food. He and his colleagues repeatedly visited more than 100 marginal fields growing maize, switchgrass or mixed prairie plants in Wisconsin and Michigan. At each site, the researchers evaluated biodiversity, looking at microbe, insect and bird populations. They also measured the “ecosystem services” that each field provided, including the rate of flower pollination, consumption of the greenhouse gas methane by soil microbes and suppression of insect pests.
Fields of maize produced more starter material for making biofuel. But fields of switchgrass and mixed prairie planted mixtures of perennial grasses and flowering plants enhanced biodiversity and improved ecosystem services, Landis and colleagues report January 13 in the Proceedings of the National Academy of Sciences. For instance, compared with maize fields, at switchgrass plots, methane consumption jumped by an order of magnitude and bird sightings doubled. The researchers also found that fields neighboring grassland plots had fewer pests and more flower pollination. One reason for the differences, Landis explains, may be that perennial grass fields don’t need to be replanted annually. Thus, they can accumulate more biodiversity and ecosystem services over time.
Though researchers knew that switchgrass and other perennial grasses have certain advantages over maize, the study is the first to look at multiple ecosystem services and animal populations at the same time, says Silvia Secchi, an agribusiness economist at Southern Illinois University in Carbondale. “Typically people look at one ecosystem service at a time,” she says. For this reason, Secchi says that land managers outside the Upper Midwest should do studies like this one to determine which bioenergy crops may best suit local ecosystems. “They’re showing a methodology,” she says. Though the study is complete for the Upper Midwest, many farmers may still be hesistant to switch to switchgrass because they are accustomed to growing maize for food and for fuel, says economist Gregory Parkhurst of Weber State University in Ogden, Utah. And to get the maximum ecosystem benefits, neighboring farmers should coordinate efforts, which may add another hurdle.
In December, the New York Times published an article about the emergence of English wineries, noting the industry’s rapid growth in the last decade as well as the fact that sparkling wines from the region have recently bested French champagnes in competitions. The story ran in the business section, not the science section, but it was about climate change. And like the article by Susan Gaidos in this issue, it illustrated how changing climate is already changing people’s lives and livelihoods. Warming temperatures in many grape-growing regions has actually helped winemakers in recent years. Longer growing seasons mean grapes produce more sugar, increasing the alcohol content of the wines, Gaidos reports. But the good times for traditional winemaking regions aren’t scheduled to last. Simulations of different climate scenarios suggest that by midcentury some of the prime wine regions in California, France and Italy will be too hot for grapes currently grown there. Instead, as this issue’s cover hints, future generations may drink wines from China, England, Canada or even Scandinavia.
Vineyards are already being planted and expanded in cooler locales once thought unsuitable for many mainstream grapes. That some in the wine industry are already moving forward to deal with current and future climate shifts shouldn’t be a surprise — it’s a pragmatic move by players in a multibillion-dollar business trying to protect profits. It offers an important lesson in embracing change, a lesson global warming is poised to teach billions of people over the next hundred years.
Technology is another major force of change today, a point highlighted in this issue’s Science Visualized. As the speed of deciphering the chemical DNA letters that make up each organism’s genetic blueprint has soared, the cost of such sequencing has dropped equally swiftly. Scientists are now on the verge of an era when they can regularly sequence individuals’ genomes, a feat bound to bring profound changes to medicine and people’s understanding of themselves. Changes of a more cosmic nature are discussed in our coverage from this year’s American Astronomical Society meeting. Andrew Grant describes a new study pointing to supernovas as a source of the cosmic dust that seeded early starbirth and reports on new work showing that gravitational lensing of supernovas might be useful for measuring the continuing expansion of the universe. It’s a good reminder that change is constant, whether we are ready for it or not.