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Fall-applied herbicides: Which weed species to target?

Published October 27, 2016
Marestail plant

URBANA, Ill. – Herbicides applied in the fall often can provide improved control of many winter annual weed species compared with similar applications made in the spring. Marestail is a prime example. More and more Illinois marestail populations are resistant to herbicides, including glyphosate and ALS-inhibiting products. University of Illinois weed scientist Aaron Hager recommends targeting emerged marestail with higher application rates of products such as 2,4-D in the fall to achieve better control come spring.

Hager is frequently asked whether a fall application needs to include one or more herbicides that provide residual control of winter annual weed species.

“Typically, the earlier the fall application is made—say, early October—the more benefit a soil-residual herbicide can provide, since emergence of winter annual weeds is often not complete. However, delaying the herbicide application until later in the fall—say, mid-November—often diminishes the necessity of a soil-residual herbicide, since most of the winter annual weeds have emerged and can be controlled with non-residual herbicides,” Hager says.

Applying a soil-residual herbicide late in the fall in hopes of having a clean field prior to planting is akin to gambling on the weather. Cold winter conditions can reduce herbicide degradation in the soil and increase herbicide persistence. This might not always be favorable since, depending on the residual herbicide, increased persistence also can cause injury to the following crop. A more moderate winter and early spring warming will increase herbicide degradation, which could result in the need for a burndown herbicide to control existing vegetation before planting.

“We recommend fall-applied herbicides to target fall-emerging winter annual species, biennials and perennials,” Hager notes. “We do not recommend fall application of residual herbicides for control of any spring-emerging annual weed species.”

Hager notes that some products have 2(ee) recommendations that suggest the product will control certain summer annual weed species following application in the fall. Certain products list “pigweed species” among these summer annuals, but Hager specifically recommends against fall application of residual herbicides to control Amaranthus species, for the following reasons:

Inconsistent performance: Performance consistency of soil-residual herbicides applied in the fall is greatly dependent on weather and soil conditions after application. “Our data suggest the greatest and most consistent control of Amaranthus species either at planting or several weeks after planting was achieved when residual herbicides were applied in the spring, not in the fall,” Hager says.

Increased selection for herbicide-resistant biotypes: Soil-applied herbicides are not immune from selection for herbicide-resistant biotypes. Following a fall application, the concentration of herbicide remaining in the spring when Amaranthus species begin to germinate will be much lower compared with the same product rate applied closer to planting.

Populations of several summer annual broadleaf weed species in Illinois demonstrate resistance to herbicides from more than one site-of-action herbicide class. Their effective management requires an integrated approach that often includes soil-residual herbicides.

“Applying these herbicides when they will be most effective against these challenging summer annual species is a critical component of an integrated management program,” Hager says.

For more information, visit the Bulletin.

News Source:

Aaron Hager, 217-333-4424

Make manure safety a priority

Published October 27, 2016
Custom application of manure after harvest
  • Recent deaths of cattle in the Illinois-Iowa-Wisconsin region point to pit gases as the culprit.
  • Hydrogen sulfide and methane gasses from liquid/slurry stores can be lethal to animals and people.
  • Remember key safety rules before agitating and emptying manure stores.
  • Make sure new or inexperienced workers are trained in safety.

URBANA, Ill. - With harvest winding down and manure application underway, it's a good time to remember manure safety, says Rich Gates, professor and Extension specialist at the University of Illinois. "Any liquid/slurry stores, when agitated, will release toxic hydrogen sulfide and methane gasses that can be lethal. Last summer, during agitation of a large manure storage tank in Wisconsin, a young farmer was killed from manure gas, along with 16 cows. This past weekend in mid-October there were three more incidents, with at least 61 cattle reported to have been killed in four incidents in the tri-state area.”

It is important to remember the key safety rules when agitating and emptying manure stores. These rules include taking steps to promote ventilation, removing workers and if possible animals, from buildings or nearby downwind structures, starting the agitation slowly, and watching for any harmful effects. Never enter an enclosed manure store without appropriate precautions, and be mindful that you can be overcome with a single breath if concentrations are high.

Facts surrounding the most recent incidents are sketchy, but custom applicators reported high to dangerous levels of hydrogen sulfide on the ground near tankers and in the cab of tractors during filling, according to a news release from Kevin Erb, University of Wisconsin Extension.

“Levels of hydrogen sulfide over 10 parts per million (ppm) should be considered dangerous, with most personal alarms set at 10 to 20 ppm,” says University of Illinois Extension educator Jay Solomon. “Levels of 1-10 ppm cause irritation, 10-50 ppm cause more serious problems with eyes and respiratory tract, and above 50 ppm can be lethal quickly.” He also noted that this latest set of mortalities occurred in naturally ventilated deep-pit beef operations.

Two fact sheets, "Safe Manure Removal Policies" and "Manure Storage Entering Procedures" are available free online from the National Pork Board and U of I Extension's ag safety website.

"Don't forget the importance of ensuring that new or inexperienced workers are also trained in safety," Gates concludes.

News Source:

Richard Gates, 217-244-2791

News Writer:

Leanne Lucas, 217-244-9085

New soy protein concentrate can be used in weanling pig diets

Published October 26, 2016


  • The digestibility of crude protein and most amino acids does not differ between soybean meal and a new source of soy protein concentrate.
  • Soy protein concentrate contained more digestible and metabolizable energy than soybean meal.
  • Phosphorus digestibility in soy protein concentrate was not different from that in soybean meal.

URBANA, Ill. – A new source of soy protein concentrate can be used in diets fed to weanling pigs without negatively affecting digestibility of energy or nutrients, according to research conducted at the University of Illinois.

“Soy protein concentrate is typically produced by using an alcohol extraction process to remove soluble carbohydrates from soybean meal," says Hans H Stein, professor of animal sciences at the University of Illinois. "However, a new soy protein concentrate has been developed which combines a non-alcohol extraction process with enzymatic treatment of soybean meal."

Stein, along with visiting scholar Maryane S. Oliveira, conducted three experiments to evaluate the nutritional value of this new soy protein concentrate product.

The soy protein concentrate contained 61.2 percent crude protein compared with approximately 47.7 percent for dehulled soybean meal. The standardized ileal digestibility (SID) of isoleucine and leucine and some dispensable amino acids was greater in soy protein concentrate compared with soybean meal, but for crude protein and most amino acids, no difference between soy protein concentrate and soybean meal was observed.

Soy protein concentrate contained 3,479 kcal/kg digestible energy (DE) and 3,299 kcal/kg metabolizable energy, compared with 3,319 and 3,093, respectively, in soybean meal. Removal of oligosaccharides, which weanling pigs cannot digest, and other soluble carbohydrates from soybean meal resulted in greater concentration of crude protein, which is likely the reason for the greater concentration of digestible energy in the soy protein concentrate.

There was no difference in the standardized total tract digestibility (STTD) of phosphorus between soy protein concentrate and soybean meal, but for both ingredients, addition of microbial phytase increased phosphorus digestibility by about 35 percent.

"Soy protein concentrate is one way of feeding high-quality soy protein to weanling pigs," says Stein. "This new technology produces soy protein concentrate that is high in digestible amino acids and energy."

Funding for this research was provided by Midwest Ag Enterprises Inc., of Marshall, MN.

The paper, "Digestibility of energy, amino acids, and phosphorus in a novel source of soy protein concentrate and in soybean meal fed to growing pigs," was published in the August issue of the Journal of Animal Science. It was co-authored by Maryane Sespere Oliveira. The full text can be found online at


OIP announces seed grant recipients for Fall 2016

Published October 25, 2016

The Office of International Programs (OIP) congratulates its International Seed Grant recipients for Fall 2016. The goal of the Seed Grant program is to support awardees in establishing a strong international relationship that will continue to expand and flourish into a larger and substantial international collaborative effort that will ultimately benefit departments, programs, the College of ACES, and the University of Illinois.

The funding of the International Seed Grants program is made possible through support provided by the Arlys Conrad Endowment Fund, and the applications are reviewed by the College of ACES International Programs and Policy Committee. OIP issues requests for seed grant proposals once a semester.

This semester’s recipients are:

Benjamin Crost, Agricultural and Consumer Economics: “Using Microcredit to Facilitate the Adoption of Postharvest Technologies: A Randomized Control Trial” (Partnering with International Rice Research Institute in The Philippines)

Erik Sacks, Crop Sciences: “Identifying genes that confer flowering‐stage heat‐tolerance in rice” (Partnering with International Rice Research Institute in The Philippines)

Matthew Wheeler & Marcello Rubessa, Animal Sciences: “New strategy for embroyo freezing” (Partnering with University of Naples, Federico II, Italy)


Soybean Innovation Lab urges farmers to adopt improved soy seeds

Published October 25, 2016

At a soybean kick-off event in Ghana, the Principal Investigator for the USAID-Feed the Future Soybean Innovation Laboratory Value Chain Research, Dr. Peter Goldsmith, has urged farmers to adopt improved soy seeds to improve plant population.

The story appeared on NEWS1 in Ghana:

From the video:

"Goldsmith revealed that high soybean plant population on ridges has proven to suppress weed population and minimize the use of chemicals for weed control in soybean fields. The event served as a platform that engaged soybean farming communities and other stakeholders in the value chain on SMART research fields. It is a platform to learn and share ideas on the season's production outlook and critical intervention needed to build best practices to improve soybean yields under Soybean Innovation Laboratory Value Chain Research. The event is aimed at improving the soybean agronomic and production interventions in the three regions of the north among more than 23,000 women smallholder farmers. Dr. Goldsmith, who spoke about the various research findings on the SMART Farm revealed that plant population, has played a key role in reducing the weed and amount of chemical application on most soybean fields."

Soybean prices remain strong

Published October 24, 2016

URBANA, Ill. – December 2016 corn and wheat futures have recovered about 12 percent and 7 percent, respectively, from the early September lows, but remain at relatively low levels. November soybean futures have recovered about 7 percent from the late September low and remain higher than expected based on the record large U.S. harvest, prospects for larger stocks by the end of the marketing year, and expectations of increased acreage in 2017.

According to University of Illinois agricultural economist Darrel Good, the recent recovery in soybean prices has been led by soybean oil prices, with December 2016 futures now 22 percent above the late July low and above the previous high price established in April. December soybean meal futures are about 6 percent above the late September low and 25 percent below the June peak.

“Soybean oil prices have been supported by expanding world vegetable oil trade and consumption and higher prices of competing vegetable oils,” Good says. “Both soybean oil futures and palm oil prices have reached the highest level in more than two years. Soybean prices have also received support from strong nearby export demand for U.S. soybeans stemming from the shortfall in South American production this year and from continued large purchases by China.”

Export inspections during the first seven weeks of the marketing year are estimated at 384 million bushels, 37 million above the total inspections a year ago. Unshipped export sales as of Oct. 13 were reported at 884 million bushels compared to 703 million a year earlier. China accounted for about 41 percent of the unshipped sales and unknown destinations, which may also be dominated by China, accounted for 44 percent of the unshipped sales.

“Soybean prices may have also received some support from the September domestic soybean crush that was larger than expected,” Good says. “The National Oilseed Processors Association reported that its members crushed 129.4 million bushels of soybeans in September, 2 percent more than crushed in September 2015. The USDA’s Oilseed Crushings, Production, Consumption and Stocks report to be released on Nov. 3 is expected to confirm that the September crush was the largest since 2007.

As U of I economist Todd Hubbs pointed out in last week’s Weekly Outlook, soybean prices for the remainder of the marketing year will be heavily influenced by the strength of export demand, particularly from China, and prospects for South American production. Production prospects will be influenced by the unfolding estimates of planted acreage and by weather and yield prospects.  Some are expecting Brazilian soybean acreage to exceed the current USDA projection, but there is also increasing chatter about the prospects for a strengthening La Niña episode and the potential for unfavorable growing season weather in South America.

Good says in the near term, soybean prices will also be influenced by the USDA’s U.S. soybean production forecast to be released on Nov. 9. The October forecast was for a crop of 4.269 billion bushels, 68 million bushels larger than the September forecast and 209 million bushels larger than the August forecast. The U.S. average yield forecast increased from 48.9 bushels in August to 50.6 bushels in September and 51.4 bushels in October.

“Based on widespread yield reports, there is a general expectation that the yield forecast will increase again in November,” Good says. “History supports that expectation as well. In the previous 40 years, the U.S. average yield forecast increased in September and again in October, as was the case this year, in 12 years. In 11 of those 12 years, the November yield forecast exceeded the October forecast. The increase ranged from 0.2 to 1.1 bushels and averaged 0.7 bushels. The lone exception was in 1981, when the November yield forecast was 0.5 bushel below the October forecast.”

According to Good, in those 11 years when the yield forecast increased in November, the yield estimate released in January after harvest exceeded the November forecast in seven years, was unchanged once, and declined in three years. The January increase ranged from 0.3 to 0.7 bushel and the decline ranged from 0.1 to 0.3 bushel.  In 1981, when the November forecast was below the October forecast, the January yield estimate was 0.4 bushel above the November forecast.  

“History points to a November U.S soybean production forecast that is 20 to 90 million bushels above the October forecast,” Good says. “If soybean production in South America rebounds as forecast, any increase in the U.S production estimate is likely to result in a forecast of year-ending stocks to exceed the current projection of 395 million bushels. The impact of larger year-ending stocks would be compounded by an increase in soybean acreage in the U.S. next year. 

“There will continue to be a lot of moving parts to the soybean price picture with the potential for a wide trading range over the next several months,” Good says. “From a risk management standpoint, current prices offer a relatively good return for producers who benefitted from above average yields this year. November 2017 futures approaching $10 per bushel also deserve a look, particularly by those intending to increase soybean acreage in 2017.”