Crop Sciences

Illinois corn and soybean harvest considerations

Published September 20, 2017

URBANA, Ill. – The USDA’s September predictions for Illinois corn and soybean yield are 189 and 58 bushels per acre, respectively. According to University of Illinois agronomist Emerson Nafziger, these are good yields after the challenges of the 2017 season. As we head into harvest, Nafziger provides considerations for farmers looking to minimize last-minute yield losses.

Soybeans
“While we don’t expect as many yields in the 80-90 bushel range as we had in 2016, pod numbers in many fields are higher than expected after the dry weather in August and September,” Nafziger says. One reason is the cooler temperatures in recent weeks; with water use lower under cooler temperatures, plants avoided the premature leaf drop that sometimes signals an early end to seed filling. Rain might help boost yields a bit, but only in fields planted late or with late-maturing varieties where plants are still green.

With high temperatures predicted for the rest of the week, seeds and pods of maturing soybeans will dry within hours, rather than days. “We need to be alert and ready to harvest as soon as plants can be cut and seed moisture drops to 13 percent,” Nafziger says. “If moisture drops to 10 percent or less during harvest, it might be worth stopping until pods and seeds take on some moisture in the evening or overnight.”

Breeding and the use of improved combine headers have reduced pod shatter at harvest, but soybean seeds with less than 10 percent moisture can crack, lowering grain and seed quality.

“Harvest is getting underway at about the same time for both corn and soybean this year, but there might need to be frequent switching between the two crops as harvest progresses in order to maximize quality and minimize losses,” Nafziger says. 

Corn
Nafziger notes that the corn crop in many fields is looking better than expected. As of Sept. 17, five percent of the state’s corn crop had been harvested, mostly in the southern half of the state. So far, reported yields have been highly variable, reflecting differences in planting (or replanting) time, soil water-holding capacity, and precipitation during critical times throughout the season.

When lack of water lowers photosynthetic rates, sugars are pulled out of the stalk into the ear to fill the grain, leaving stalks more susceptible to stalk-rotting fungi and lodging. Nafziger recommends that farmers should check fields for stalk strength, especially where leaves dried earlier than expected. However, good growing conditions in July likely increased the deposition of stalk-strengthening lignin, making stalks less likely to break. “As long as winds stay relatively calm, lodging is not expected to be much of a threat, especially in those parts of the state that received more rainfall in July and August,” he says.

Most of central and northern Illinois are approximately 150 growing degree days (GDD) behind normal since May 1. According to Nafziger, below-normal temperatures in recent weeks have slowed grain-filling rates and delayed maturity of the corn crop. But the cooler temperatures probably have been positive for yields by extending the water supply into mid-September. “With GDD accumulation rates above normal now, a lot of fields will reach physiological maturity quickly, and grain will start to dry down. High temperatures mean rapid grain moisture loss.  We’ve seen corn grain lose moisture as much as one percentage point of moisture per day under high temperatures, especially if it's breezy,” he says.

Dry conditions over the past month have limited the spread of ear rots. “Most kernels have the bright yellow color of healthy grain, and if the grain can be harvested without an extended period of wet weather, we expect grain quality to be good. Harvesting at high moisture, drying at high temperatures, or storing grain without proper care can all compromise quality, however,” Nafziger says. “While we like to finish harvest early, the threat of loss in yield or quality from delaying harvest to October is low. But waiting too long isn’t good, either; delaying harvest until grain moisture drops below 16 or 17 percent can increase loss due to shelling of kernels onto the ground as ears go into the combine.”

Nafziger notes that test weight is an issue that comes up every year during corn harvest. He says test weights lower than the standard of 56 pounds per bushel have many people thinking that something went wrong during grain fill. Likewise, above-normal test weights are often taken as a sign that kernels filled extraordinarily well, and that yield was maximized. “Neither of these is very accurate – high yields often have test weights less than 56 pounds, and grain from lower-yielding fields can have high test weights,” he says.

Test weight is bulk density – it measures the weight of grain in 1.24 cubic feet, which is the volume of a bushel. Kernel density is the weight of a kernel divided by its volume, not including air the way bulk density does. Kernel density is a more useful measure of kernel soundness and quality than is test weight – it’s often used by the food corn processing industry – but it is harder to measure than test weight.

“A typical kernel density might be 90 pounds per ‘bushel’ (1.24 cubic feet) of actual kernel volume,” Nafziger explains. “So, a 56-pound bushel of corn grain is about 62 percent kernel weight and 38 percent air. Kernels with higher density tend to produce higher test weights, but only if they fit together without a lot of air space. For example, popcorn has small, high-density kernels that fit together well, and its test weight is typically 65 pounds per bushel.”

Hybrid genetics, growing conditions, and grain moisture at the time it is weighed can all affect test weight. If kernels appear to be well-filled without a shrunken base, which can signal that grain fill ended prematurely, it’s likely that yield was not compromised even if test weight is less than 56 pounds per bushel.

“For reasons that go back to an earlier time, though, corn test weight needs to be at least 54 pounds per bushel in order to be sold as U.S. No. 2 corn, which is the most common market class. Corn with a test weight of 52 or 53 might not be docked in price if it can be blended with higher test weight grain to reach the minimum. That’s much easier to do in a year when test weights are generally good. We expect 2017 to be such a year,” Nafziger says.

For more on the 2017 harvest, read Nafziger’s recent post on The Bulletin.

Oct 10 Monsanto Room, ACES Library, Information & Alumni Center ACES Town Hall with Dean Kidwell

The time is RIPE to transform agriculture and feed the world

Published September 15, 2017
Steve Long and Don Ort
Researchers led by Stephen Long (left) and Don Ort (right) will continue transformative work to increase yields of food crops for farmers worldwide through Realizing Increased Photosynthetic Efficiency with the support of a five–year, $45-million reinvest

URBANA, Ill. – Political and agricultural leaders gather at the University of Illinois today to see transformative work by scientists in the Realizing Increased Photosynthetic Efficiency (RIPE) research project, which has already demonstrated yield increases of 20 percent. A $45 million, five-year reinvestment from the Bill & Melinda Gates Foundation (BMGF), the Foundation for Food and Agriculture Research (FFAR), and the U.K. Department for International Development (DFID) will enable the researchers to continue their work to address the global food challenge.

“Today's report on world hunger and nutrition from five UN agencies reinforces our mission to work doggedly to provide new means to eradicate world hunger and malnutrition by 2030 and beyond,” said RIPE Director Stephen Long, the Gutgsell Endowed Professor of Crop Sciences and Plant Biology at the Carl R. Woese Institute for Genomic at Illinois. “This investment is timely. Annual yield gains are stagnating and means to achieve substantial improvement must be developed now if we are to provide sufficient food for a growing and increasingly urban world population when food production must also adapt sustainably to a changing climate.”

“While no single strategy is going to get us there, our successes in redesigning photosynthesis are exciting,” said RIPE Deputy Director Don Ort, USDA/ARS Photosynthesis Research Unit and the Robert Emerson Professor in Plant Biology and Crop Sciences at Illinois. “RIPE has validated that photosynthesis can be engineered to be more efficient to help close the gap between the trajectory of yield increase and the trajectory of demand increase.”

Building on half a century of photosynthesis research at Illinois, including several landmark discoveries enabled by state and federal partnerships, RIPE researchers simulated the 170-step process of photosynthesis. They used their computer models to identify seven potential pipelines to improve photosynthesis—and with the support of an initial $25 million, five-year grant from the Gates Foundation—began work in 2012 to try to turn their ideas into sustainable yield increases.

Last year, in a study published in the journal Science, the team demonstrated that one of these approaches could increase crop productivity by as much as 20 percent – a dramatic increase over typical annual yield gains of one percent or less. Two other RIPE pipelines have now led to even greater yield improvements in greenhouse and preliminary field trials.

“Our modeling predicts that several of these improvements can be combined to achieve additive yield increases, providing real hope that a 50 percent yield increase in just three decades is possible,” Long said. “With the reinvestment, a central priority will be to move these improved photosynthesis traits into commodity crops of the developed world, like soybeans, as well as crops that matter in the developing world, including cassava and cowpeas.”

RIPE and its funders will ensure that their high-yielding food crops are globally available and affordable for smallholder farmers to help feed the world’s hungriest and reduce poverty, particularly in Sub-Saharan Africa and Southeast Asia.

But we still have a long road ahead of us, Long said.

“It takes about fifteen years from discovery until crops with these transformative biotechnologies are available for farmers,” he said. “It will therefore be well into the 2030s before such superior crops are seen at scale in farmers’ fields.”

Long and Ort are also part of the Department of Crop Sciences in the College of Agricultural, Consumer and Environmental Sciences at Illinois.

Sep 27 Twitter - use #askACES to ask your questions! #askACES: Figuring out the Farm Bill

Teachable, ultra-compact, autonomous phenotyping robot introduced to investors, market

Published September 12, 2017
TerraSentia robot
TerraSentia robot

URBANA, Ill. – Investors and executives in the agricultural industry are getting a first look at TerraSentia, a new-to-the-market agricultural robot that autonomously measures crop traits, developed at the University of Illinois. TerraSentia is being unveiled on Sept. 11 to 13 at the Ag Innovation Showcase in St. Louis, bringing agricultural innovators together with investors to help realize the future of the industry.
 
The start-up company EarthSense, Inc. announced it has filed a provisional patent and is now taking pre-orders for the agricultural robot TerraSentia, which will be ready for the 2018 growing season. Developed at the University of Illinois, with support from the Advanced Research Projects Agency - Energy (ARPA-E), the robot will cost early adopters $4,999 – a fraction of the cost of hiring laborers to measure germination, conduct stand counts, and other monotonous jobs.
 
The robot’s developer, Girish Chowdhary, a professor in the Department of Agricultural and Biological Engineering at U of I, envisions a fleet of these ultra-compact robots roving fields doing simple tasks that will free up precious human capital to work on the big picture.
 
“Our robot will do the exhausting, time consuming, error-prone part – collecting field data – giving plant breeders and scientists more time to analyze it and make key decisions,” said Chowdhary. “What would take a team of researchers tromping through fields with tape measures and other tools to do in several days, our robot can do in several hours.”
 
Currently, the robot can autonomously count plants and measure stem width to help estimate biomass for corn, sorghum, and soybeans. Work is underway to teach it to measure stem, angle plant height, corn ear height, leaf area index, early vigor, and biomass, and to identify diseases.
 
Early adopters who order by Nov. 31, 2017, will get 100 hours of one-on-one consulting to teach their robot to detect and quantify other traits that drive their business or research. They will also benefit from an exclusive buyback program and a one-year, all-inclusive warranty.
 
TerraSentia comes equipped with two visual cameras, a tablet app featuring first-person view, and secure cloud software used to store data and teach the robot. The ultra-compact robot weighs less than 15 pounds and is just 11 inches wide to fit in most crop rows. At 8.5 hours per charge, the robot’s battery lasts a full workday.
 
The robot can be further customized with GPS to enable autonomous navigation and custom mounts for additional sensors including multi-spectral cameras, hyperspectral cameras, stereoscopic and structured light cameras, and LIDAR.
 
For more information or to order TerraSentia, contact EarthSense, Inc. CEO Chinmay Soman via email at hello@earthsense.co or visit earthsense.co.

Airline industry could fly thousands of miles on biofuel from a new promising feedstock

Published September 11, 2017
PETROSS researchers
PETROSS researchers Deepak Kumar (left) and Vijay Singh (right)

URBANA, Ill. – A Boeing 747 burns one gallon of jet fuel each second. A recent analysis from researchers at the University of Illinois estimate that this aircraft could fly for 10 hours on bio-jet fuel produced on 54 acres of specially engineered sugarcane.

Plants Engineered to Replace Oil in Sugarcane and Sweet Sorghum (PETROSS), funded by the Advanced Research Projects Agency - Energy (ARPA-E), has developed sugarcane that produces oil, called lipidcane, that can be converted into biodiesel or jet fuel in place of sugar that is currently used for ethanol production. With 20 percent oil - the theoretical limit - all the sugar in the plant would be replaced by oil.

"Oil-to-Jet is one of the direct and efficient routes to convert bio-based feedstocks to jet fuel," said Vijay Singh, Director of the Integrated Bioprocessing Research Laboratory and Professor in the Department of Agricultural and Biological Engineering at U of I. "Reducing the feedstock cost is critical to improving process economics of producing bio-jet fuel. Lipidcane allows us to reduce feedstock cost."

This research analyzed the economic viability of crops with different levels of oil. Lipidcane with 5 percent oil produces four times more jet fuel (1,577 liters, or 416 gallons) per hectare than soybeans. Sugarcane with 20 percent oil produces more than 15 times more jet fuel (6,307 liters, or 1,666 gallons) per hectare than soybeans.

"PETROSS sugarcane is also being engineered to be more cold tolerant, potentially enabling it to be grown on an estimated 23 million acres of marginal land in the Southeastern U.S.," said PETROSS Director Stephen Long, Gutgsell Endowed Professor of Plant Biology and Crop Sciences at the Carl R. Woese Institute for Genomic Biology  at U of I. "If all of this acreage was used to produce renewable jet fuel from lipid-cane, it could replace about 65 percent of national jet fuel consumption."

"We estimate that this biofuel would cost the airline industry $5.31 per gallon, which is less than most of the reported prices of renewable jet fuel produced from other oil crops or algae," said Deepak Kumar, postdoctoral researcher in the Department of Agricultural and Biological Engineering at U of I and lead analyst on the study.

This crop also produces profitable co-products: A hydrocarbon fuel is produced along with bio-jet fuel or biodiesel that can be used to produce various bioproducts. The remaining sugar (for plants with less than 20 percent oil) could be sold or used to produce ethanol. In addition, biorefineries could use lipidcane bagasse to produce steam and electricity to become self-sustainable for their energy needs and provide surplus electricity, providing environmental benefits by displacing electricity produced with fossil fuels.

The paper "Biorefinery for combined production of jet fuel and ethanol from lipid-producing sugarcane: a techno-economic evaluation" is published by Global Change Biology Bioenergy (10.1111/gcbb.12478).

PETROSS (Plants Engineered to Replace Oil in Sugarcane and Sorghum) is a research project transforming sugarcane and sweet sorghum to naturally produce large amounts of oil, a sustainable source of biofuel. PETROSS is supported by the Advanced Research Projects Agency-Energy (ARPA-E), which funds initial research for high-impact energy technologies to show proof of concept before private-sector investment.

Weed seed destructor demonstration planned at Illinois

Published September 8, 2017
Harrington seed destructor
Aaron Hager (left) and Adam Davis (right) with the Harrington Seed Destructor

URBANA, Ill. – Farmers battling herbicide resistant weeds could add a new weapon to their arsenal, but it’s not a chemical. The Harrington Seed Destructor destroys this year’s weed seeds during harvest, preventing establishment in the spring. Farmers can see it in action Oct. 12 at the University of Illinois.

“I’ll admit I was a bit skeptical about whether the HSD would work on waterhemp, but using it during last year’s harvest reduced waterhemp populations in this year’s crops,” says Adam Davis, ecologist in the Department of Crop Sciences and with the USDA Agricultural Research Service.

The field tour will begin at 1 p.m. at the Crop Sciences South First Street Facility at 4202 South 1st Street in Savoy. The tour will also include visits to two nearby field sites.

Attendees are not required to register, and all are welcome. For more information on the Harrington Seed Destructor, visit http://go.illinois.edu/hsd, or contact Taylor Stewart at 217-300-6299 or taylors@illinois.edu.

Related Links:

Harrington Seed Destructor http://go.illinois.edu/hsd

Herbicide rotation ineffective against resistance in waterhemp

Published September 6, 2017

URBANA, Ill. – Farmers have been battling herbicide-resistant weeds for generations. A common practice for most of that time has been to rotate between different herbicides every season. But despite farmers’ best efforts, herbicide resistance has grown through the years, with some weed populations showing resistance to not one but four or five different herbicides. A new study from the University of Illinois explains why herbicide rotation doesn’t work.

“If you were to ask farmers what is the one thing you can do to delay resistance evolution, they’ll say rotate herbicides. This study shows that’s not true,” says Pat Tranel, Ainsworth Professor in the Department of Crop Sciences at U of I.

Herbicide resistance results from random genetic mutations that keep weeds from being harmed by a particular herbicide. When farmers continually spray the same herbicide year after year, those with the mutation, referred to as a resistance allele, survive and reproduce. Over time, the proportion of plants with the resistance allele grows.

Conventional thinking says that any defense trait—in this case, herbicide resistance—should come at a cost to the plant. It might be well protected against the herbicide, but it might not grow as tall, or flower as early. When the trait reduces a plant’s reproductive output, that’s known as a fitness cost.

A fitness cost to herbicide resistance should be apparent in years when alternative herbicides are used. “If plants have glyphosate resistance, but they’re sprayed with 2,4-D, for example, the majority of those plants will die because they’re not resistant to 2,4-D. But no herbicide kills 100 percent of the weeds, resistant or not,” Tranel says. “You have to think about the small percentage that live.

“If there’s a high fitness cost to the glyphosate resistance allele, most of the surviving plants will be small or will flower late and they won’t produce many seeds. But if the fitness cost is low, those plants will produce just as many seeds as plants that don’t have the allele. Herbicide rotation relies on the assumption that the fitness cost is high.”

To test that assumption, Tranel and his research team designed a simple, if time-consuming, experiment. They took female waterhemp plants with no resistance alleles and allowed them to be pollinated by males with resistances to five different herbicides. Because female waterhemp plants can produce as many as a million seeds, it was easy to get the 45,000 they needed to start the experimental population.  

They scattered seeds on the soil floor of a greenhouse and just let them grow. When females started producing seeds, they were collected to start the next generation. Between generations, the researchers removed all the plants and made sure no seeds remained in the soil. The cycle was repeated for six generations over three years.

How could the study test the efficacy of herbicide rotation if no herbicides were sprayed? It comes back to fitness cost. Remember, the assumption is that without the herbicide, the resistance allele offers the plant no benefit, and could carry a cost. The researchers were allowing those fitness costs a chance to play out during the study.

“If the resistance alleles had a high fitness cost, we should have seen them decrease in frequency or disappear over the six generations,” Tranel says. Instead, the alleles for almost all five resistance types were essentially unchanged.

The allele that confers resistance to ALS-inhibiting herbicides was statistically lower after six generations, but the decrease was tiny in terms of real numbers. “The frequency decreased by less than 10 percent a year,” Tranel says. “At the rate it was decreasing, even if a farmer used an alternative herbicide for 9 years, the frequency of resistance to ALS inhibitors would only be cut in half.”

Waterhemp has two known strategies to ward off glyphosate-based herbicides, such as Roundup, and the researchers tested the frequency of both.

“Plants with one type of glyphosate-resistance mechanism make multiple copies of the target site for glyphosate, a gene called EPSPS. And that’s what we found went away; the proportion of plants with multiple copies of EPSPS decreased about 15 percent with each generation,” Tranel says. “But I want to emphasize something: even though it decreased quite a bit, it didn’t disappear by any stretch. If you applied glyphosate, that resistance mechanism would come back even if you waited six years between applications.”

The other glyphosate-resistance mechanism involves the same gene. This time, it’s a specific mutation in the EPSPS gene that guards the plant against the effects of glyphosate. The researchers found that the mutation in EPSPS actually increased about 10 percent in each generation. Tranel thinks it may have been easier for one mechanism to replace the other because they both involve the same gene.

“This study tells us that fitness cost isn’t going to help you much in terms of herbicide resistance, so even long rotations aren’t going to work,” Tranel says. “I tell farmers, ‘Once you have resistance, you’re stuck with it.’ It gives us that much more incentive to do the right things to avoid resistance in the first place. That means using multiple herbicides, using a PRE and coming back with a POST. If you have escapes, getting out of your tractor and getting rid of them before they set seed. Because if they set resistant seed, this study tells you that you will have that resistance trait for life.”

The article, “Limited fitness costs of herbicide-resistance traits in Amaranthus tuberculatus facilitate resistance evolution,” is published in Pest Management Science. Tranel’s co-authors include Chenxi Wu and Adam Davis, from U of I. The study was supported by a grant from USDA NIFA [grant no. 2012-67013-19343].  

Could switchgrass help China’s air quality?

Published September 5, 2017
Loess Plateau

URBANA, Ill. – Researchers from the United States and China have proposed an idea that could improve China’s air quality, but they’re not atmospheric scientists. They’re agronomists.

“China’s poor air quality is caused by a combination of coal burning and particulates from soil erosion. The Loess Plateau is the major source of erosion in China, and air quality there is just terrible. If erosion in the Loess Plateau can be improved, air quality will improve,” says D.K. Lee, an agronomist in the Department of Crop Sciences at the University of Illinois.

Although the region has been farmed for millennia, much of China’s Loess Plateau could be described as a barren moonscape: dry, dusty, and prone to erosion. In fact, the distinctive loess soils in the area have been called the most erodible in the world. In a massive soil conservation effort, the Chinese government is creating incentives for farmers to plant sustainable and erosion-reducing cropping systems, including orchards, forests, and perennial grasses. Researchers from U of I are recommending switchgrass.

“When we’re looking at revegetation, ideally we’re planting something that can bring in revenue for farmers. Switchgrass produces a lot of biomass that can be harvested and burned as a cleaner source of energy,” Lee says. “Not only can switchgrass reduce air pollution by holding the soil, if it is burned instead of coal, it can reduce air pollution in a second way.”

Switchgrass is stress tolerant and small-scale testing in the area has shown that it can produce plenty of biomass even with limited irrigation and fertilizers. But, Lee says, cultivar selection and management practices will depend on where switchgrass is planted within the Loess Plateau. “Most areas should be okay, but elevation, latitude, and moisture level should be taken into account when selecting the appropriate switchgrass cultivar for the area.” 

Although switchgrass has been introduced in China, it hasn’t caught on as a biomass crop yet. That’s where the research team— including experts in switchgrass cultivar selection, agronomy, and management—comes in, and their new article provides this information in practical terms for future evaluation by Chinese scientists and government agencies.

“Stopping erosion in the Loess Plateau is not going to be easy. It was the birthplace of agriculture in Asia, and it has been farmed for several thousand years. The land has been intensively farmed. But when I visited, I saw people out there planting trees by hand. It’s changing. And maybe switchgrass can be part of that change,” Lee says.

The article, “Switchgrass as a bioenergy crop in the Loess Plateau, China: Potential lignocellulosic feedstock production and environmental conservation,” is published in the Journal of Integrative Agriculture. Lee’s co-authors include Danielle Cooney, Hyemi Kim, Moon-Sub Lee, Jia Guo, and Lauren Quinn from U of I, and Chen Shao-lin and Xu Bing-cheng from China’s Northwest A & F University in Yangling. The work was supported by the USDA National Institute of Food and Agriculture’s Hatch Project.

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D.K. Lee, 217-333-7736
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