- Plant-derived proteins are less expensive than animal proteins, but sometimes cause nutritional problems in weanling pigs.
- A new University of Illinois study determined digestibility of energy and amino acids in soy protein concentrate ground to three different particle sizes.
- Soy protein concentrate ground to 180 micrometers may be used as an alternative to animal proteins in diets for weanling pigs.
URBANA, Ill. – Plant-derived proteins are less expensive than animal proteins if used in weanling pig diets, but may contain anti-nutritional factors that can negatively affect gut health and growth performance. However, results of a new study from the University of Illinois indicate that soy protein concentrate (SPC) may be partly or fully substituted for animal proteins without adverse effects.
“We determined digestibility of crude protein, amino acids, and energy in SPC ground to three particle sizes,” says U of I animal sciences professor Hans H. Stein. “We also investigated the effects of substituting SPC for animal proteins on weanling growth performance.”
Soy protein concentrate is derived from defatted soy flakes by removing soluble carbohydrates and some nonprotein constituents. Three particle sizes – 70, 180, and 700 micrometers – were tested because earlier work showed that particle size of soybean meal affects digestibility of amino acids in weanling pigs.
In the group’s first experiment, pigs were fed diets containing soybean meal, fish meal, or SPC ground to one of the three particle sizes. Ileal digesta were collected and analyzed for amino acid and crude protein content.
Standardized ileal digestibility (SID) of crude protein was not different among the three diets containing SPC, but diets with SPC ground to 70 or 180 micrometers had greater crude protein digestibility than the traditional protein sources. The SID of several amino acids, including tryptophan, was also greater in diets containing SPC ground to 70 or 180 micrometers, compared with the other diets.
Stein explains that these results differed from similar studies using soybean meal, in which particle size had a greater influence on digestibility. “It could be that alcohol extraction used in SPC processing improves digestibility, making it unnecessary to reduce particle size further to obtain the same results.”
In a second experiment, weanling pigs were fed corn mixed with each of the protein sources used in the first experiment. The goal was to measure apparent total tract digestibility of gross energy and the digestible and metabolizable energy in each diet.
“There were no differences in digestible and metabolizable energy among the three SPC particle sizes, but SPC ground to 180 micrometers contained more digestible energy than corn, soybean meal, and fish meal,” Stein says.
Finally, the researchers investigated the effects of SPC on growth performance and blood characteristics. In this experiment, pigs were fed combinations of fish meal, spray-dried protein plasma, and SPC ground to 180 micrometers. The different diets did not change growth performance overall and no reduction in performance was observed if SPC was used instead of fish meal or spray-dried protein plasma.
“Results of this experiment indicated that diets based on soybean meal and SPC can be fed to weanling pigs without negative effects on growth performance during the initial four weeks after weaning,” Stein says.
Altogether, results of the three experiments indicate that SPC ground to 180 micrometers may be used as an alternative to animal proteins in weanling pig diets.
The article, “Nutritional value of soy protein concentrate ground to different particle sizes and fed to pigs,” is published in Journal of Animal Science. The research was funded by Selecta.
Experts discuss state of the art in drainage water quality
URBANA, Ill. – Nearly 80 water quality experts met last week in Champaign, Illinois, to discuss the latest in farm drainage water quality. The occasion was the joint annual meeting of the North Central Extension and Research multi-state committee on drainage design and management and the Agricultural Drainage Management Systems Task Force. Illinois’ 10 million acres of tile drainage means it has more tile-drained acres than any other state, thus providing the ideal backdrop for the meeting.
“We’re bringing together the best ‘drainage minds’ in the country,” says University of Illinois assistant professor of water quality, Laura Christianson. “That includes researchers, Extension personnel, and leaders in the drainage industry. It’s a chance for us all to catch up and learn from one another what’s new, what’s working, and what’s not working so well.”
The big topics this year were saturated buffers, controlled drainage, and denitrifying bioreactors, all of which reduce nitrogen loss from tile drains. Controlled drainage additionally reduces the flow of drainage water that moves downstream without negatively influencing crop yields. Researchers from the College of Agricultural, Consumer and Environmental Sciences at U of I are actively engaged in answering research questions about these conservation drainage practices, and are working to understand how they can help Illinois producers meet nutrient loss reduction goals.
Producers may be encouraged to hear that some conservation drainage practices are being fast-tracked by agencies that can help interested landowners with financial and technical assistance. Ruth Book, state conservation engineer with the USDA Natural Resources Conservation Service, talked about how NRCS is approaching conservation drainage.
“Normally, NRCS waits until most of the research has been done before establishing official standards for conservation practices,” Book says. “Saturated buffers and denitrifying bioreactors show so much promise that we rolled out our conservation practice standards earlier in the process than usual, while we are still in the learning phase of the development. In this continuous learning process, we have already identified criteria that need to be changed, and have updated our saturated buffer standard accordingly.”
Attendees were also updated by representatives from industry, the U.S. Environmental Protection Agency, and land-grant researchers from 11 states. Five U of I ACES graduate students presented research posters on topics ranging from the use of cover crops to the application of LiDAR imagery for drainage design.
For more information on conservation drainage practices, visit the following online resources:
Putting a price tag on biodiversity
- Conservationists have long sung the praises of carbon sequestration and biodiversity.
- A new model attaches a dollar amount to the loss or gain of species in grassland ecosystems.
- One finding is that the biggest benefit comes from adding species to the least diverse lands.
URBANA, Ill. – Talk to just about any biologist long enough and the conversation will steer toward the benefits of biodiversity. Although the ecological benefits of biodiversity are well documented, those benefits have rarely been expressed in dollars and cents. A team of economists and ecologists, including University of Illinois professor of environmental economics Amy Ando, has developed one of the first models to assign a dollar value to the loss or gain of species in an ecosystem. This new work offers an economic argument for preserving biodiversity.
”Biodiversity has value in its own right, as people marvel at the beauty and variety of the many faces of nature,” says Ando. “But those intrinsic values can be hard to quantify. In this study, we pinned down the monetary value of one particular practical service that biodiversity provides to people: carbon storage.” The research team was led by Bruce Hungate, director of the Center for Ecosystem Science and Society at Northern Arizona University. The findings are published in Science Advances.
To build the model, the researchers first had to identify some measurable service of biodiversity that society has priced. Although biodiversity provides many valuable services, concern about climate change has led economists to put a dollar value on the abatement of climate-warming carbon emissions (ranging between roughly $40 and $400 per metric ton). And now there’s a $175 billion global carbon market that pays for activities that remove carbon from the atmosphere.
Biodiversity could enter the game through a 4-billion-year-old form of carbon storage that plants provide: photosynthesis. Plants absorb carbon dioxide for energy and growth, storing the carbon in their leaves, stems, and roots, and later transferring it to the soil through decay. The key is to link biodiversity and carbon storage in a quantitative way. So researchers asked: Will changing the number of plant species in an ecosystem affect the amount of carbon it stores over time?
The National Socio-Environmental Synthesis Center (SESYNC) convened the team of scientists, which analyzed data from two long-term experiments in Minnesota grasslands that measured how plant and soil carbon changed with the number of plant species in a plot. Modeling results over 50 years, they estimated the “marginal” increase in carbon storage, or how much additional carbon is stored for every species added to the mix.
Each additional species in a grassland plot increased the plot’s overall carbon storage, on average. One reason for this gain may be that new species can fill new niches, yielding more overall growth.
With more species came diminishing returns in cumulative carbon storage. A change from five to six species stored almost 10 times more carbon than a change from 15 to 16 species, showing that the biggest benefit came from adding species to the least diverse plots.
At small scales, about 2.47 acres, going from one to two plant species over a 50-year time period would store an additional 9.1 metric tons of carbon, potentially saving $804 per 2.47 acres based on a mid-range estimate ($137 per metric ton) of the social cost of carbon. At larger scales, cost savings could hypothetically be significant. For example, adding just one species to the approximately 29.5 million acres of cultivated lands restored to grasslands by USDA’s Conservation Reserve Program could save over $700 million. The biggest cost savings come from restoring the most degraded, species-poor lands.
These numbers underestimate the total value of increased biodiversity because biodiversity confers economic value in many ways beyond storing carbon. “Biodiversity means products like wood, food, and fuel, and services like recreation, water purification, and flood protection, all of which could be quantified using our approach”, says Hungate. “Money is a language that speaks, and showing the economic value of biodiversity underscores the importance of conservation and the policies that support it.”
Although the value of biodiversity is more complex than just one economic measure, this new research takes a bold step toward understanding the value of nature.
The study, “The economic value of grassland species for carbon storage,” is published in Science Advances. Authors are Bruce Hungate, Edward B. Barbier, Amy W. Ando, Samuel P. Marks, Peter B. Reich, Natasja van Gestel, G. David Tilman, Johannes M.H. Knops, David U. Hooper, Bradley J. Butterfield, and Bradley J. Cardinale.
The research was supported in part by funding from SESYNC and the USDA-NIFA.
Scientists engineer sugarcane to produce biodiesel, more sugar for ethanol
• Bioenergy crops grown on U.S. soil can produce inexhaustible and sustainable domestic source of fuel, lessening our reliance on limited and often foreign fossil fuel reserves.
• Naturally, sugarcane plants produce sugar but hardly any oil. Researchers developed sugarcane that produces enough oil for biodiesel production as well as even more sugar for ethanol production.
• This dual-purpose bioenergy crop could produce biofuel on marginal land in the Southeastern United States that is not well suited to most food crops.
URBANA, Ill. - A multi-institutional team led by the University of Illinois has proven sugarcane can be genetically engineered to produce oil in its leaves and stems for biodiesel production. Surprisingly, the modified sugarcane plants also produced more sugar, which could be used for ethanol production.
The dual-purpose bioenergy crops are predicted to be more than five times more profitable per acre than soybeans and two times more profitable than corn. More importantly, sugarcane can be grown on marginal land in the Gulf Coast region that does not support good corn or soybean yields.
“Instead of fields of oil pumps, we envision fields of green plants sustainably producing biofuel in perpetuity on our nation’s soil, particularly marginal soil that is not well suited to food production,” says Stephen Long, Gutgsell endowed professor of Plant Biology and Crop Sciences. Long leads the research project Plants Engineered to Replace Oil in Sugarcane and Sweet Sorghum (PETROSS) that has pioneered this work at the Carl R. Woese Institute for Genomic Biology at U of I.
“While fuel prices may be considered low today, we can remember paying more than $4 per gallon not long ago,” Long says. “As it can take 10-15 years for this technology to reach farmers’ fields, we need to develop these solutions to ensure our fuel security today and as long as we need liquid fuels into the future.”
Published in Biocatalysis and Agricultural Biotechnology, this paper analyzes the project’s first genetically modified sugarcane varieties. Using a juicer, the researchers extracted about 90 percent of the sugar and 60 percent of the oil from the plant; the juice was fermented to produce ethanol and later treated with organic solvents to recover the oil. The team has patented the method used to separate the oil and sugar.
They recovered 0.5 and 0.8 percent oil from two of the modified sugarcane lines, which is 67 percent and 167 percent more oil than unmodified sugarcane, respectively. “The oil composition is comparable to that obtained from other feedstocks like seaweed or algae that are being engineered to produce oil,” says co-author Vijay Singh, director of the Integrated Bioprocessing Research Laboratory at Illinois.
“We expected that as oil production increased, sugar production would decrease, based on our computer models,” Long says. “However, we found that the plant can produce more oil without loss of sugar production, which means our plants may ultimately be even more productive than we originally anticipated.”
To date, PETROSS has engineered sugarcane with 13 percent oil, 8 percent of which is the oil that can be converted into biodiesel. According to the project's economic analyses, plants with just 5 percent oil would produce an extra 123 gallons of biodiesel per acre than soybeans and 350 more gallons of ethanol per acre than corn.
Currently, the project is seeking commercial investors to achieve 20 percent oil production, the theoretical limit according to the project’s computer models. For more information about opportunities to collaborate or invest in this work, contact Vijay Singh at email@example.com or 217-333-9510.
The PETROSS project and this work are 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.
The paper “Evaluation of the quantity and composition of sugars and lipid in the juice and bagasse of lipid producing sugarcane” is published by Biocatalysis and Agricultural Biotechnology. Co-authors include: Haibo Huang (Virginia Polytechnic Institute and State University); Robert A. Moreau (USDA/ARS); Michael J. Powell (USDA/ARS); Zhaoqin Wang (University of Illinois); Baskaran Kannan (University of Florida); Fredy Altpeter (University of Florida), and Aleel K. Grennan (University of Illinois).
Two new mechanisms for herbicide resistance found in Palmer amaranth
- Last year, scientists discovered a gene mutation responsible for Palmer amaranth’s resistance to PPO-inhibiting herbicides.
- Because not all PPO-resistant Palmer amaranth plants had the mutation, University of Illinois researchers went looking for another explanation.
- The team discovered two additional mutations that confer resistance to PPO-inhibitors, and developed a diagnostic test can be used in other labs.
URBANA, Ill. – Palmer amaranth is a nightmare of a weed, causing yield losses up to 80 percent in severely infested soybean fields. It scoffs at farmers’ attempts at control, having evolved resistance to six classes of herbicides since its discovery in the United States 100 years ago. And now, scientists have discovered it has two new tricks up its sleeve.
About a year ago, a group of researchers discovered Palmer is resistant to the herbicide class known as PPO-inhibitors, due to a mutation—known as the glycine 210 deletion—on the PPX2 gene.
“We were using a quick test that we originally developed for waterhemp to determine PPO-resistance based on that mutation. A lot of times, the test worked. But people were bringing in samples that they were fairly confident were resistant, and the mutation wasn’t showing up. We started to suspect there was another mechanism out there,” says University of Illinois molecular weed scientist Patrick Tranel.
Tranel and his colleagues decided to sequence the PPX2 gene in plants from Tennessee and Arkansas to see if they could find additional mutations. Sure enough, they found not one, but two, located on the R98 region of the gene.
“Almost all of the PPO-resistant plants we tested had either the glycine 210 deletion or one of the two new R98 mutations. None of the mutations were found in the sensitive plants we tested,” Tranel says.
Furthermore, some of the resistant plants had both the glycine 210 deletion and one of the new R98 mutations. Tranel says it is too early to say what that could mean for those plants. In fact, there is a lot left to learn about this resistance mechanism.
“We don’t know what level of resistance the new mutations confer relative to glycine 210,” Tranel says. “There are a lot of different PPO-inhibiting herbicides. Glycine 210 causes resistance to all of them, but we don’t know yet if the R98 mutations do.”
The team is now growing plants to use in follow-up experiments. Tranel hopes they will be able to determine how common the three mutations are in any given population. “That way,” he says, “when a farmer sends us a resistant plant and it doesn’t come back with the glycine 210 deletion, we will be able to tell him how likely it is that he’s dealing with another one of these mutations.”
In the meantime, other research groups or plant testing facilities could use the new genetic assay to detect the mutations in Palmer samples. Tranel hopes they will. “The more labs testing for this, the more we learn about how widespread the mutation is,” he says.
The article, “Two new PPX2 mutations associated with resistance to PPO-inhibiting herbicides in Amaranthus palmeri,” is published in Pest Management Science. The work was supported by a grant from the USDA’s National Institute of Food and Agriculture.
UI study determines areas vulnerable to riparian erosion
- Riparian erosion is one of the major causes of sediment and contaminant load to streams.
- Soil type and land use are two of the most important variables in riparian erosion.
- Identifying the most vulnerable areas for riparian erosion allows conservation and management practices to focus on areas needing the most attention and resources.
Urbana, Ill. - Researchers at the University of Illinois collaborated with colleagues in Oklahoma to identify areas along a riparian zone, that is, alongside rivers that are susceptible to erosion.
Maria Chu, an assistant professor in agricultural and biological engineering (ABE), and Alejandra Botero-Acosta, a Ph.D. student in ABE, developed a modeling framework which they used to identify those areas in the Fort Cobb Reservoir Experimental Watershed (FCREW) in southcentral Oklahoma. The FCREW has three sub-watersheds: Cobb, Lake, and Willow. Chu, Botero-Acosta, and their colleagues used readily available USDA environmental data from the area.
“A healthy riparian buffer intercepts suspended solids, nitrogen, and phosphorous,” says Botero-Acosta, “reducing sediment load and nutrient pollution in the rivers. We found in our literature review that 50 percent of the sediments in the river were coming from the riparian zone. We wanted to identify those locations so conservation and management practices can be focused on those points.”
Predicting riparian erosion at the watershed scale is challenging because of the complex interactions between the different variables that govern soil erosion and the inherent uncertainties in measuring those processes. In this study, Botero-Acosta says they found that soil type and land use were the two most important variables.
“The most vulnerable areas for erosion were found to be located at the upper riparian zone of the Cobb and Lake sub-watersheds. The soil there is sand and silt, which is very prone to erosion,” she says. “Land use was also important. Livestock grazing and row crops thinned the vegetation, so that increased erosion.”
Hydrological variables that are dynamic, such as rainfall, lateral and overland inflow, and discharge, were not as significant in predicting the location of erosion. However, Botero-Acosta says “In order to convert flow into velocity, we needed a cross section of the river, and we didn’t have that data. For future work, implementing that kind of data will give us better results regarding hydrological variables, because we do think that discharge can affect riparian erosion.”
Botero-Acosta says mitigating riparian erosion is ultimately beneficial to the population at large. “A watershed provides ecosystems services to the community, which people sometimes take for granted. Fresh water to drink, water to irrigate crops, oxygen-rich water to support fish populations, those are all connected to a healthy watershed.”
Chu will be conducting a similar study in the Upper Sangamon Watershed, near Decatur. The Sangamon watershed is almost twice the size of the Fort Cobb watershed, and the area is approximately 90 percent agricultural, as opposed to 60 percent agricultural in Oklahoma. Chu received funding from the USDA’s National Institute of Food and Agriculture to do a hydrologic assessment of the watershed. The study will use a suite of hydrologic and environmental models to simulate different land management practices and their effects on ecosystems services such as water clarity, nutrient reduction, and fish species richness.
The Fort Cobb study, “Riparian erosion vulnerability model based on environmental features,” is written by Chu and Botero-Acosta, along with colleagues Jorge Guzman, research hydrologist at the Center for Spatial Analysis, University of Oklahoma; Daniel Moriasi, research hydrologist at USDA-ARS Grazinglands Research Laboratory, El Reno, Oklahoma; and Patrick Starks, soil scientist at USDA-ARS Grazinglands Research Laboratory, El Reno, Oklahoma. It appears in the Journal of Environmental Management, and a pdf of the full paper is available online.