URBANA, Ill. – Early this week, a brief respite from heavy rains allowed for some corn and soybean planting (or replanting) to resume in many parts of Illinois. But, given the amount of recent precipitation, many farmers are concerned about nitrogen loss and wondering if they need to apply more. Emerson Nafziger, professor in the Department of Crop Sciences at the University of Illinois, provides some insight.
“The return of cooler weather along with the rainfall slowed nitrification - the conversion of ammonium to nitrate - slightly, and also slowed the denitrification process,” Nafziger explains. “Both nitrification and denitrification are biological processes, so they happen faster at higher temperatures. We know from finding nitrate in the soil that there has been a lot of nitrification. Denitrification requires both saturated soils and warm soils, and there has been less of it.”
Soils with standing water are slow to warm up, limiting the rate of denitrification. But it is happening in some areas where water is still standing. In those locations, it will be some time before a crop can be planted, and Nafziger says adjustments to fertilizer nitrogen may be in order as the crop gets established.
Ammonium moves little in the soil, but when it is converted to nitrate, it can move. “We know from our research that nitrogen applied last fall was about 70 percent nitrate by early May, and ammonia applied in March or April was more than half nitrate when the weather turned wet,” Nafziger says.
Somewhat surprisingly, Nafziger found little change in soil nitrogen levels from the unusually heavy rainfall, “We sampled six trial sites both before and after the heavy rainfall of late April and early May, and found virtually no change in soil nitrogen content. We expect that mineralization of soil organic matter added some nitrogen between samples, and that is no longer around, so some nitrogen moved out. The good news is that most of the nitrogen added as fertilizer is still in the soil. That may not be the case in every part of every field, but we don’t see any reason to imagine that most of the nitrogen we applied has been lost.”
Soil drainage is an important factor in movement of water and nitrate. Soil texture is a critical component of drainage, but field tiles change the relationship between texture and water movement.
“As an example, a typical Drummer silty clay loam soil in eastern Illinois allows hardly any water to move through it unless the soil is tile-drained. Tile becomes the exit route for soil nitrogen into surface waters, replacing denitrification as the main way nitrogen is lost in such soils. So, tile drainage changes the assumption that heavy-textured soils will lose nitrogen to denitrification while lighter-textured soils lose more to leaching,” Nafziger explains.
While it’s possible that some nitrogen may be lost before crop uptake begins in a few weeks, Nafziger says that a decision to apply more nitrogen than planned is premature. As soils dry, rainfall returns to normal, and plants grow, roots will begin to draw water and dissolved nitrogen towards the surface, and mineralization will kick into high gear. “Last year,” Nafziger recalls, “under good temperatures and without unusually heavy rainfall, we saw mineralization provide as much as 150 pounds of nitrogen per acre to the crop.”
One indication that the topsoil has not been stripped clean of nitrogen is the recovery of green leaf color that has been happening as the soil dries out. “Most fields are not as dark green as we saw at this point in 2016, but as the root system starts to expand and as soils continue to warm, this will change,” Nafziger says. “The corn crop at this point looks the way it does not because of lack of nitrogen, but due to the effects of temperature and rainfall on crop growth and early development.”
While it is premature to revise nitrogen management based on what has happened so far, farmers shouldn’t rule out the possibility that the crop may need more nitrogen. The good news is that farmers still have time to make such decisions. As long as soil conditions continue to improve, a crop provided with normal amounts of fertilizer nitrogen rarely runs out during vegetative development. According to Nafziger, this year will be no exception.
Nafziger plans to continue soil sampling to learn more about the status of soil nitrogen over the next two months. But, he says, because similar weather patterns have not happened this early in the season in recent years, he cannot easily predict what will happen later in the season.
“Nitrogen deficiency develops over time, and is almost always more related to current soil moisture than to the amount of soil nitrogen. So, if soils do not get extra wet or extra dry over the next month, this season could turn out to be much more typical than we expect.”
For more information, see the Bulletin.
Blue and purple corn: Not just for tortilla chips anymore
URBANA, Ill. – Consumers today insist on all-natural everything, and food dyes are no exception. Even if food manufacturers are willing to make the change, current sources of natural dyes are expensive and hard to come by. Now, a large University of Illinois project is filling the gap with colored corn.
“Most natural colors come from things like wine skins, red carrots, and beets. The problem with that is most of the product is wasted in extracting the coloring. It’s not good value,” says Jack Juvik, a geneticist in the crop sciences department at U of I.
Juvik and an interdisciplinary team have been experimenting with purple and blue corn varieties, noting that health-promoting pigments known as anthocyanins are located in the outer layers of the corn kernel. That makes a big difference, economically.
“You can process corn in different ways to remove only the outer layer. The rest can still be fed into the corn supply chain to make ethanol or grits or any of the other products corn is already used for. That outer layer becomes a value-added co-product,” Juvik says.
The team has covered a lot of bases since the $1.4 million project began in 2014. For example, they identified the optimal milling process and demonstrated that corn-derived anthocyanins remain stable in food products. What’s left is to find the most potent sources of the pigments for future corn breeding.
In a recent study, Juvik and his colleagues looked at anthocyanin type and concentration in nearly 400 genetically distinct lines of colored corn. They grew these lines in Illinois to see if anthocyanin concentration stayed constant from generation to generation – a critical quality for breeding new varieties.
Peruvian types had some of the highest anthocyanin concentrations, and they held up throughout multiple generations. “That’s good news. It means we can select for the trait we’re interested in without worrying whether it will be expressed in new environments,” Juvik says.
The next step will be getting those mighty Peruvian genes into high-yielding corn hybrids selected for production in the Midwest. If Juvik is successful, blue or purple corn could come to a field near you.
The article, “A survey of anthocyanin composition and concentration in diverse maize germplasm,” is published in the Journal of Agricultural and Food Chemistry. Co-authors Michael Paulsmeyer and Laura Chatham are graduate students and Talon Becker a post-doctoral scholar in the crop sciences department at U of I. Megan West and Leslie West worked for The Kraft Heinz Company, which supported the project. Additional support came from the Illinois Corn Grower’s Association and Monsanto.
New study sheds light on origins of life on Earth through molecular function
- Debate exists over how life began on Earth, but a new study provides evidence for a “metabolism-first” model.
- Scientists at the University of Illinois mined the Gene Ontology database to trace the origins and evolution of molecular functions through time.
- The study shows metabolism and binding arose first, followed by the functional activities of larger macromolecules and cellular machinery.
URBANA, Ill. – In the primordial soup that was early Earth, life started small. Elements joined to form the simple carbon-based molecules that were the precursors of everything that was to come. But there is debate about the next step.
One popular hypothesis suggests that ribonucleic acid (RNA) molecules, which contain the genetic blueprints for proteins and can perform simple chemical reactions, kick-started life. Some scientists refute this idea, however, saying RNA is too large and complex a molecule to have started it all. That group says simpler molecules had to evolve the ability to perform metabolic functions before macromolecules such as RNA could be built. This idea is appropriately named “metabolism-first,” and new evidence out of the University of Illinois backs it up.
“All living organisms have a metabolism, a set of life-sustaining chemical transformations that provide the energy and matter needed for the functions of the cell. These metabolic transformations are assumed to have occurred very early in life, in primitive Earth. Organisms probably replaced chemical reactions already going on in the planet and internalized them into cells through development of enzymatic activities,” says Gustavo Caetano-Anollés, bioinformatician and professor in the Department of Crop Sciences at U of I.
Caetano-Anollés and Ibrahim Koç, a visiting scholar in the department, found evidence for the “metabolism-first” hypothesis by studying the evolution of molecular functions in organisms representing all realms of life. For 249 organisms, their genomes – or complete set of genes – were available in a searchable database. What’s unique about this particular resource, known as the Gene Ontology (GO) database, is the fact that for each gene product – a protein or RNA molecule – a set of terms describing its function goes with it.
“You can take an entire genome that represents an organism, like the human genome, and visualize it through the collection of functionalities of its genes. The study of these ‘functionomes’ tells us what genes do, instead of focusing on their names and locations. For example, we can find out what kinds of catalytic, recognition, or binding activities a gene product has, which is much more intuitive,” Caetano-Anollés notes. “The best way to understand an organism is through its functions.”
According to Caetano-Anollés, the number of times a function appears in a genome provides historical information. So the team took the GO terms describing all of the molecular functions in each organism and counted them up. The idea was that an ancient function, such as the catalytic activity of metabolism, is likely shared by all organisms and will be found in large numbers. On the other hand, more recent functions are found in lower numbers and in smaller subsets of organisms.
The team used the information and advanced computational methods to construct a tree that traced the most likely evolutionary path of molecular functions through time. At the base of the tree, close to its roots, were the most ancient functions. The most recent were close to the crown.
At the base of the tree, corresponding to the origin of life on Earth, were functions related to metabolism and binding. “It is logical that these two functions started very early because molecules first needed to generate energy through metabolism and had to interact with other molecules through binding,” Caetano-Anollés explains.
The next major advancements were functions that made the rise of macromolecules possible, which is when RNA might have entered the picture. Next came the machinery that integrated molecules into cells, followed by the rise of functions allowing communication between cells and their environments. “Finally, as you move toward the crown of the tree, you start seeing functions related to highly sophisticated processes involving things like muscle, skin, or the nervous system,” Caetano-Anolles says.
The research doesn’t just shed light on the past. Knowing the progression of these molecular functions through time can help predict where life on Earth is headed. “People think of evolution as looking backwards,” Caetano-Anollés says. “But we could use our chronologies and methodologies to ask what novel molecular functions will be generated in the future.”
The work has applications for bioengineering, an emerging field that uses biological information and computation to produce novel molecules. Engineered molecules could combat disease and improve the quality of everyday life, according to Caetano-Anollés. “The best way to reengineer biological molecules with novel and useful molecular functions is to learn principles from clues left behind in their past,” he says.
The article, “The natural history of molecular functions inferred from an extensive phylogenomic analysis of gene ontology data,” is published in PLoS One.
Herbicide considerations for replanted corn
URBANA, Ill. – Following recent and excessive precipitation, many Illinois corn producers are now scrambling to replant before the final planting date on June 5. While there are many agronomic considerations associated with replanting, University of Illinois weed scientist Aaron Hager says farmers should keep weed control/herbicide issues in mind.
“Herbicide-resistance traits in the replanted hybrids should be taken into account,” says Hager, an associate professor in the Department of Crop Sciences at U of I. “For example, if you initially planted a glyphosate-resistant corn hybrid and have areas that need to be replanted, you can replant with a similar glyphosate-resistant hybrid or choose to replant with one that’s not glyphosate-resistant. If you take the second option, you will have to take special precautions to reduce drift with any postemergence glyphosate application, as these plants will be extremely sensitive to glyphosate.”
Hager says farmers should consider the interval between the last herbicide application and corn replanting. “For soil-applied corn herbicides, replanting can proceed whenever field conditions are feasible,” he says. “However, for some postemergence corn herbicides, there are intervals between application and replanting. If replanting a corn field previously treated with Spirit, for example, four weeks must elapse between the herbicide application and planting. For NorthStar, the interval is 14 days. For Permit or Yukon, you need to wait one month.”
While most soil-applied herbicides allow more than one application per season, a few, such as Acuron and Resicore, can be applied only once. In instances where small areas of a field will be replanted, Hager says some farmers may elect to simply replant without applying any additional residual herbicide. “However, if you decide to make a second application of a particular corn herbicide, keep in mind that many product labels indicate a maximum per-acre rate that can be applied during one growing season,” he notes.
If farmers need to control corn from the first planting, Hager recommends tillage as an effective first choice. Several herbicides can control existing corn plants if tillage isn’t an option, but Hager says careful attention must be given to what, if any, herbicide resistance trait(s) the existing corn plants contain.
“As you might imagine,” Hager says, “glyphosate is very effective for controlling existing stands of corn sensitive to glyphosate. Corn replanting can occur immediately after application, but control might be improved if at least 24 hours elapses between application and replanting. Glyphosate also would control sensitive weeds that might have emerged with the initial stand of corn. Be very cautious to avoid drift when spraying glyphosate, especially if spraying around wet holes.”
Other herbicides to control emerged corn include paraquat and glufosinate (only hybrids sensitive to glufosinate), although previous research with these herbicides has demonstrated that complete control is not always achieved. Performance of these products can be improved when applied in combination with atrazine or metribuzin. Paraquat and glufosinate would also control a broad spectrum of emerged weeds.
Corn hybrids resistant to glyphosate, glufosinate, or both can be controlled with Select Max prior to replanting field corn. According to label specifications, farmers should apply 6 fluid ounces per acre to control glyphosate-resistant field corn up to 12 inches tall.
“Applications should include NIS and AMS (do not use a COC or MSO in this particular use), and care must be taken to avoid in-field overlaps or excessive injury to the replanted corn might occur. Glyphosate can be tank-mixed with the Select Max to control emerged broadleaf weed species. Do not replant fields treated in this way sooner than six days after application or severe injury to the replanted corn can occur,” Hager says.
Product labels of ACCase-inhibitors including Poast, Poast Plus, Fusion, Fusilade, Select, and Assure II require an interval between application and rotation to or replanting with grass crops such as corn. These intervals range from 30 (Poast, Poast Plus, Select) to 60 (Fusion, Fusliade) to as many as 120 (Assure II) days, making these products unlikely choices for this particular use. Severe injury to replanted corn can occur if soil residues of ACCase-inhibiting herbicides are taken up by emerging corn plants.
For more information and handy reference tables, please visit the Bulletin.
2017-18 Market prospects for corn and soybeans
URBANA, Ill. - In the May 10 World Agricultural Supply and Demand Estimates (WASDE) report, the USDA released the first projections for U.S. corn and soybean supply and demand in the 2017-18 marketing year. While the projections on crop production received quite a bit of the focus, the projections for marketing-year consumption levels provide essential information in forming expectations for corn and soybean prices in the 2017-18 marketing year, says University of Illinois agricultural economist Todd Hubbs.
The consumption projections for both crops reflect the potential market size under a scenario consisting of substantial supplies and lower prices.
The U.S average corn yield is projected at 170.7 bushels per acre, and production is projected at a record 14.06 billion bushels. The U.S. average soybean yield is projected at 48 bushels per acre. Soybean production is projected at a record 4.255 billion bushels. “The currently projected corn yield maintains the previous projections from USDA presentations and does not reflect, as of yet, any of the potential issues associated with the cold and wet spring experienced by large portions of the Corn Belt,” Hubbs says. “Yield potential for both crops will unfold over the next few months and will be determined by weather conditions.
“Additionally, planted acreage levels are yet to be determined and still have a significant amount of uncertainty due to planting conditions. The USDA’s June Acreage report will provide more clarity as of June 30.”
In the corn market, corn use for ethanol is forecast at 5.5 billion bushels, 50 million bushels above the revised projection for the current year. The corn use for ethanol projection is a record consumption level for a marketing year and reflects the strong levels of domestic ethanol production thus far in the 2016-17 marketing year, Hubbs explains. “The importance of ethanol exports and continued growth in gas demand are key variables in meeting this projection. Corn exports are projected at 1.875 billion bushels, 350 million bushels lower than the revised projection of 2.25 billion bushels for the current marketing year. Export projections sit at levels between 1.8 to 2.0 billion bushels, which was common before the 2016-17 marketing year.
“Lower prices may help to stimulate exports, but the large crops of South American corn are expected to limit demand growth in export markets and generate significant competition for U.S. corn,” he adds.
Feed and residual use of corn is projected at 5.425 billion bushels, 75 million bushels lower than the 5.5 billion bushels projected for the current marketing year. Despite growth in livestock production, Hubbs says the projection represents a lower level of consumption and reflects the impact of distillers’ grains and ample supplies of other feed grains on corn use in feed. The feed and residual projection is below the peak consumption of 6.15 billion bushels in 2004-05 and 2005-06 when distillers’ grains supplies were still small. Consumption for all uses, including non-ethanol domestic processing, is projected at 14.30 billion bushels, 345 million bushels less than projected for the current marketing year.
For the soybean market, the domestic crush is projected at 1.950 billion bushels, 25 million bushels above the projection for the current year, and constitutes a record projected crush level. Exports are projected at 2.15 billion bushels, 100 million bushels above the projection for the current marketing year. The record level of soybean exports in the presence of a large world soybean crop reflects an expectation of a 5 percent increase in global soybean imports. “This growth in world demand for soybeans is dependent on continued demand growth in Asian markets,” Hubbs says. “Total consumption, including seed and residual use, is projected at 4.235 billion bushels, 142 million bushels above use during the current year. Projections reflect expectations of continued demand growth both domestically and in foreign markets.”
Ending stocks of U.S. corn for the 2017-18 marketing year are projected at 2.110 billion bushels, down 185 million bushels from current marketing-year ending stock projections. The reduction in ending stocks is directly related to the expectation of significantly lower production levels and reduced growth in corn consumption. Ending stocks of U.S. soybeans are projected at 480 million bushels, up 45 million bushels from current marketing-year ending stock projections.
“The increase in ending stocks is directly related to the expectation of significantly higher production levels,” Hubbs says.
The 2017-18 marketing-year average farm price of corn is projected in a range of $3.00 to $3.80. “Current bids for harvest delivery in much of Illinois are slightly above the middle of that range. If there are substantial planting delays and slow progress through mid-May, production and acreage concerns may increase and create a stronger price response,” Hubbs says. “The 2017-18 average price for soybeans is projected in a range of $8.30 to $10.30, with harvest bids in much of Illinois currently below the middle of the range. It is still too early for significant production concerns for soybeans. The ability for U.S. soybeans to expand exports next year will be essential in meeting the increase in soybean consumption and will merit close monitoring as we move into the next marketing year.”