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New models better predict field working days

Published January 28, 2016
Wet field
Wet spring conditions make planting difficult. New models developed by U of I researchers improve prediction of field working days. Photo courtesy of Adam Davis.
  • Farmers and risk managers rely on accurate predictions of soil workability to plan field working days, but weather variability is making predictions less reliable.
  • New models, developed by University of Illinois researchers, provide a way for farmers and risk managers to make more accurate predictions of field working days.
  • The models improve field working day estimates from early spring through mid-summer, encompassing a wide variety of field operations, including soil preparation, planting and pest management applications.

URBANA, Ill. – Farmers and crop insurers depend on seasonal predictions of weather and soil workability to select appropriate cultivars, make decisions about planting and harvest dates, forecast yield, and determine risk. However, climate change-induced weather variability is making it harder to predict workable conditions for crop production systems. University of Illinois researchers developed new models that improve the ability to forecast field working days, even under changing climatic conditions. 

“On any given day, a farmer is going to know very precisely whether the soil is going to be workable,” says U of I ecologist Adam Davis. “What we’re trying to do is take that ‘farmer sense’ and convert it into something measurable and predictable.”

Field working day prediction models are primarily useful in risk assessment.

“These models examine the relationship between management timing and factors such as changing climate, machinery selection, or simply year-to-year weather variability. An unbiased model is required to appropriately quantify these risks.”

One of the models, which was based on 52 years of Illinois soil moisture data and weekly field working day data, eliminated systematic prediction biases at the state level and significantly reduced them at the crop reporting district level. This model could be applied to regions outside Illinois, since USDA working day reports are available for most other states.

The errors that existed in earlier field working day predictions occurred most frequently in April and May, an interval that previous predictions suggested would be favorable for planting. In recent years, however, April and May have been substantially wetter compared with the 30-year average.

“Going forward, if there are going to be more really wet days in mid-April through mid-May, that’s going to greatly reduce the chances of timely corn planting. If you reduce the chance of timely planting, you’re suddenly looking at more of an overlap between the anthesis-silking interval of corn and drought periods in the summer,” Davis notes. 

Climate models predict warmer, wetter springs and drier, hotter summers. Since publishing this study, the team has integrated future climate scenarios like these into their field working day models. This will eventually allow them to make more specific recommendations to Illinois farmers, extension specialists, and risk managers. 

"Optimization of agricultural field workability predictions for improved risk management," appears in Agronomy Journal. Lead author Bradley Tomasek is now in a Ph.D.  program at Duke University. Co-authors Marty Williams and Adam Davis are Research Ecologists with the USDA Agricultural Research Service, and faculty members in the UIUC Crop Sciences Department. Funding was provided by the USDA Agricultural Research Service.

The article is available online at https://dl.sciencesocieties.org/publications/aj/abstracts/107/2/627.

News Source:

Adam Davis, 217-333-9654

Palmer amaranth could affect Illinois soybean yield

Published January 27, 2016
Palmer amaranth plant
Young Palmer amaranth plant. Photo courtesy of Aaron Hager.
  • Palmer amaranth, a major weed in southern soybean cropping systems, is able to complete its life cycle and affect soybean yield in Illinois.
  • Although Palmer amaranth currently exists at low levels in Illinois, it is capable of causing greater economic damage if continued seed introductions and mismanagement occur.   
  • Farmers should learn to identify Palmer amaranth at the seedling stage and be aggressive in removing it from fields and equipment.

URBANA, Ill. – Although agricultural weed Palmer amaranth (Amaranthus palmeri) primarily impacts southern U.S. states, new research shows it could soon spread further north and damage soybean yields in Illinois.

“We did a common garden study in southern, central, and northern Illinois to ask if different varieties of Palmer amaranth from the south complete their life cycle in all three locations and cause yield loss in soybean. The short answer is yes: there are no current climate limitations to any of the genotypes that we looked at,” said University of Illinois weed ecologist Adam Davis. “This is a serious weed.”

Illinois farmers are well acquainted with its aggressive cousin, tall waterhemp (Amaranthus tuberculatus), significant infestations of which can cause soybean yield losses of up to 30 percent. Palmer amaranth is an even bigger threat, causing soybean yield losses up to 80 percent in severe cases.

“It’s a real economic game-changer,” Davis noted. In the study, Davis and his colleagues only allowed Palmer amaranth to compete with soybean for five weeks to avoid seed dispersal and local infestation after the plants had reached maturity. Still, in that time, soybean yield loss reached 30 percent in some locations.

Unfortunately, Palmer amaranth does not conform to experimental rules in the field.

“It can complete its life cycle in a very short period of time. Even if you killed early season populations, if it comes up again in late summer, it can still produce seed by harvest time.”

Palmer amaranth already exists in Illinois, but it hasn’t become a major problem. “The short take-home message from this research is that Palmer amaranth is mainly seed limited in Illinois,” meaning the reason it’s not here in greater numbers is simply that not enough seeds have been introduced yet. 

To avoid population explosion in Illinois and elsewhere, farmers should learn to identify and remove Palmer amaranth before it goes to seed. Davis also urges farmers to buy certified seed, including cover crop seed and meals, and to be careful about cleaning equipment, especially if it has been purchased out of state. He also suggests diversifying cropping systems to include winter annuals. Additional guidelines for identification and management of Palmer amaranth are published by the University of Illinois Weed Science Extension service.

"Palmer amaranth (Amaranthus palmeri) damage niche in Illinois soybean is seed limited," appears in Weed Science. The paper was co-authored by Aaron Hager from the U of I, Brian Schutte from New Mexico State University, and Bryan Young from Purdue University. Funding was provided by the USDA Agricultural Research Service and the Illinois Soybean Association.

The article is available online at http://www.bioone.org/doi/abs/10.1614/WS-D-14-00177.1.

News Source:

Adam Davis, 217-333-9654

2016 Agriculture Technology Innovation Summit planned for Feb. 18

Published January 25, 2016

URBANA, Ill. - The University of Illinois at Urbana-Champaign is holding a summit on agriculture technology innovation and opportunities for entrepreneurship on Feb. 18 at the iHotel and Conference Center in Champaign.

Modern agriculture is being transformed by a confluence of new technologies and record-breaking investments in the sector to support new ventures. The University of Illinois is uniquely positioned where agriculture, engineering, and technology intersect. Topics such as drones, software, predictive analytics, sensors, data, and precision agriculture will be discussed.

This event will include speakers from industry, investors in agriculture, researchers, and examples of agriculture entrepreneurship. The one-day program will include keynote speakers, panel discussions, and a lunch program. The event is co-hosted by the U of I College of Agricultural, Consumer and Environmental Sciences, the U of I Research Park, and the Office of Corporate Relations. 

The deadline for registration is February 4. Registration is free and is open at http://researchpark.illinois.edu/agtechsummit. The summit begins at 8 a.m. on Feb. 18 and concludes at 3 p.m.

An outline of the agenda for the summit is also available at the website, with a complete program available soon. 

Soybean meal produced in U.S. has greater energy values when fed to pigs than previously estimated

Published January 21, 2016

URBANA, Ill. – Differences in soil type, variety of soybeans, climate, or processing conditions can cause the same crop to have different nutritional value when produced in different locations. However, feed composition tables combine values from crops grown all over the world. Results of recent research at the University of Illinois indicate that book values for energy in soybean meal underestimate the energy value of soybean meal produced in the United States.

"In the experiments we've conducted using soybean meal here at the University of Illinois, we have calculated values for digestible and metabolizable energy that were consistently 200 to 400 kcal/kg greater than values in feed composition tables," explained Hans H. Stein, professor of animal sciences at Illinois. "Most of those experiments have been conducted using soybean meal derived from beans grown in Illinois. So we decided to compare soybean meal from Illinois with soybean meal produced in other states, to determine if our results were due to better nutritional value of soybean meal produced in Illinois."

Stein led a team that evaluated the energy content of 22 sources of soybean meal obtained from crushing plants in four zones in the United States. Michigan, Minnesota, and South Dakota comprised Zone 1; Georgia, Indiana, and Ohio made up Zone 2; Zone 3 was Iowa, Missouri, and Nebraska, and Zone 4 was Illinois.

Concentrations of digestible energy (DE), metabolizable energy (ME), and net energy (NE) were the same for soybean meal from Zones 1, 2, and 4, but soybean meal from Zone 3 contained less DE, ME, and NE than soybean meal from Zones 1 and 2.

Results did not confirm the hypothesis that soybean meal from Illinois contained more energy than soybean meal from other areas of the U.S. Instead, results indicate that soybean meal produced in the United States – regardless of growing area – provides more energy to pigs than what is indicated in current feed composition tables, including values published in the most recent tables from the National Research Council.

According to Stein, if soybean meal produced in other countries has reduced energy value compared with U.S. soybean meal, it lowers the average values published in feed composition tables, but this hypothesis has not been experimentally verified. It is also possible that soybean meal produced from modern genetic material simply contains more digestible energy than soybean meal produced from previous varieties of soybeans.

"We know that for broiler chickens, soybean meal produced in the United States has greater ME values than soybean meal produced in Argentina."

Stein said more studies are needed to compare the DE, ME, or NE of soybean meal produced in different countries and fed to pigs. But the bottom line is that soybean meal produced in the United States contains at least 200 kcal more DE, ME and NE than indicated by current book values. These new energy values will increase the economic value of soybean meal and reduce diet costs if used in diet formulations for pigs.

The research was supported by a grant from the Illinois Soybean Association and the paper, "Concentrations of digestible, metabolizable, and net energy in soybean meal produced in different areas of the United States and fed to pigs," was co-authored by Kelly Sotak-Peper and Caroline González-Vega, both from the U of I, and published in a recent edition of the Journal of Animal Science. The full text can be found online at https://www.animalsciencepublications.org/publications/jas/abstracts/93/12/5694.

 

News Source:

Hans H. Stein, 217-333-0013

News Writer:

Leanne Lucas, 217-244-9085

Weed blasting offers new control method for organic farmers

Published January 21, 2016
Weed blaster
Hand-held weed blasting unit used in the study
  • Organic growers now have a new tool to control weeds: abrasive weeding, or “weed blasting,” which uses an air compressor to blast organic grit at weed seedlings during vulnerable growth stages.
  • Weed blasting can reduce weed biomass in organic tomato and pepper crops by up to 97 percent, while maintaining crop yields similar to hand-weeded control plots.
  • Organic fertilizers, such as soybean meal, can be used as abrasive grit, which could mean farmers could control weeds and fertilize their crop in a single pass.

URBANA, Ill. – Weeds are a major scourge for organic growers, who often must invest in multiple control methods to protect crop yields. A relatively new weed control method known as abrasive weeding, or “weed blasting,” could give organic growers another tool. The method, recently field-tested at the University of Illinois, is surprisingly effective.   

In conjunction with plastic mulch, abrasive weeding reduced final weed biomass by 69 to 97 percent compared to non-weeded control plots, said U of I agroecologist Samuel Wortman.

Abrasive weeding involves blasting weed seedlings with tiny fragments of organic grit, using an air compressor. For the current study, grit was applied through a hand-held siphon-fed sand-blasting unit connected to a gas-powered air compressor, which was hauled down crop rows with a walk-behind tractor. The study looked at a number of grit sources: walnut shells, granulated maize cob, greensand, and soybean meal. If applied at the right plant growth stage, the force of the abrasive grit severely damages stems and leaves of weed seedlings.   

Wortman found no significant differences between the grit types in terms of efficacy. “When it leaves the nozzle, it’s at least Mach 1 [767 mph],” Wortman noted. “The stuff comes out so fast, it doesn’t really matter what the shape of the particle is.” Because ricocheting particles can pose a risk to the applicator, Wortman advises using protective eyewear.  

Blasted grit does not discriminate between weed and crop seedlings, which makes it important to use this method in transplanted crops that are substantially larger than weed seedlings at the time of grit application. Although some visible damage occurred on stems and leaves of both tomato and pepper crops, the damage did not affect marketable fruit yield. Studies are ongoing to determine whether abrasions on crop tissues could result in increased susceptibility to disease, but early results show little effect.

Importantly, plots with plastic mulch and one or more blasting treatment achieved the same fruit yields seen in hand-weeded plots, and 33 to 44 percent greater yields than in non-weeded control plots.  

An additional benefit of weed blasting is the potential for growers to use organic fertilizers, such as soybean meal, as blasting material. “We expect that abrasive weeding could contribute between 35 and 105 kg nitrogen per hectare [31 – 94 lbs per acre] to soil fertility.” The idea that a grower could both fertilize and kill weeds in a single pass is appealing, but it is still unknown whether the fertilizer would be available for plant uptake within critical windows.

According to Wortman’s research, weed blasting does affect some weeds more than others. Essentially, the smaller the seedling, the better. Also, seedlings whose growing points are aboveground (annual broadleaf species) are more susceptible to blasting than seedlings whose growing tips are located belowground (grasses and broadleaf perennials). Finally, Wortman noted that the presence of plastic mulch seemed to factor strongly into the equation. Weed blasting alone “is not a silver bullet, but it is an improvement,” he said.

The method is now being tested in different horticultural crops, including broccoli and kale, with and without additional weed control methods. Early results suggest that the presence of polyethylene mulch or biodegradable plastic mulch strongly enhances the success of weed blasting, as compared with straw mulch and bare soil. Wortman and his collaborators have also developed a mechanized grit applicator, which they are currently testing.

The paper, "Air-propelled abrasive grits reduce weed abundance and increase yields in organic vegetable production," was published in Crop Protection. Funding was provided by the National Institute of Food and Agriculture’s Organic Agriculture Research and Extension Initiative. The article can be found online at http://www.sciencedirect.com/science/article/pii/S0261219415300788.

High resolution images are available for this story at https://www.youtube.com/watch?v=0VMGmSWzvQE

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