Study shows insect farming byproduct boosts soil health, reduces crop damage
Jan. 29, 2026
By John Lovett
University of Arkansas System Division of Agriculture
Fast Facts
- Insect frass delivered two to four times greater nutrient efficiency than poultry litter
- Soybeans grown with insect frass showed 38 to 45 percent less leaf damage from pests
- Insect farming projected to generate 5.5M tons of frass in North America by 2033
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Download PHOTOS of insect frass and the researchers
FAYETTEVILLE, Ark. — With insect farming projected to produce millions of tons of insects in the coming years, Arkansas Agricultural Experiment Station researchers offer evidence that the insect farming byproduct called “frass” can improve soil health and reduce insect damage in soybean crops.
Insect frass includes manure, as well as the insects’ molted skin and any leftover insect food. In addition to poultry feed, insects are grown as feed for fish, emerging markets in swine and pet food, as well as human food in energy bars.
“For every 1 pound of insect meal, you get up to four times more frass, so the question came up whether it could be used as a soil amendment,” said Helen Amorim, lead author of the study and a research scientist with the experiment station in the department of crop, soil and environmental sciences. Amorim is also part of the U.S. Department of Agriculture’s Agricultural Research Service in the Poultry Production and Product Safety Research Unit in Fayetteville. The experiment station is the research arm of the University of Arkansas System Division of Agriculture.
Their study on black soldier fly frass as a soil amendment in soybean and switchgrass field trials showed that frass worked as well as chicken litter, even when applied in lower amounts.
The research on insect frass as a soil amendment was initiated by co-author Amanda Ashworth, a soil scientist with USDA-ARS, as a collaboration with Ty-Pro, a joint venture between Tyson Foods Inc. and Protix, to promote waste management solutions for the growing industry of insect farming.
Sustainable protein production and reducing food waste are key agricultural issues, and the mass-reared insect industry has the potential to tackle both, according to a description of the MINIstock Grand Challenge for Sustainable Agriculture, with Ann Donoghue, the former research leader at the USDA-ARS Poultry Production and Product Safety Research Unit. MINIstock is short for Model for Insect Inclusion.
Complementary research investigating insects as a source of the essential amino acid methionine was recently awarded a nearly $1 million grant by the USDA’s National Institute of Food and Agriculture. The project will be led by Adnan Alrubaye, an assistant professor of poultry science in the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas. Alrubaye is also part of the experiment station. Arkansas was one of only seven states nationwide to receive the grant.
Cutting leaf damage
For Amorim, the most interesting points about the study on insect frass as a soil amendment were that it showed frass not only worked as well as poultry litter, but frass had “something else,” and they’re not quite sure what it is.
“We are thinking that there are plant-growth-promoting beneficial microbes that poultry litter might not have,” Amorim said. “This will be the next step in our research.”
Frass used as a soil amendment in soybean plots also reduced leaf damage from insect pests by 38 to 45 percent compared to control plots and soybeans grown with poultry litter.
The results illustrate, for the first time under field conditions, the potential for insect frass to enhance plant resistance to herbivory, or pest feeding, Amorim said.
The study, published in the Journal of Environmental Quality, assessed the impacts of black soldier fly frass on soil fertility, crop growth and quality compared to poultry litter in irrigated and non-irrigated soybean and non-irrigated switchgrass. The test plots received either no amendment for a control, a standard rate of poultry litter, a low rate of frass, which equaled the poultry litter’s nitrogen content, or a high rate of frass that was double the poultry litter’s rate of nitrogen content.
Black soldier fly eggs were supplied by Protix B.V. in the Netherlands. The insects were reared in Ty-Pro’s research lab in Springdale, and the frass was collected periodically by Ty-Pro’s team for a thermal treatment to ensure the manure was pathogen-free.
Nutrient efficiency
Interestingly, the low frass rate resulted in two to four times greater nutrient efficiency than either the high frass rate or poultry litter in both organic soybean and switchgrass systems, offering similar yields despite lower nutrient inputs, Amorim noted.
The findings, Amorim said, provide foundational knowledge for frass utilization as an organic soil amendment and growth promoter, closing nutrient loops through waste recovery during insect rearing.
Soil amendment vs. fertilizer
Insect frass regulation is developing in Canada, Europe and the United States. Europe has defined a regulatory approach to insect frass, with baseline standards for its production as an organic fertilizer and calling for a heat treatment process.
The Frass Institute, a nonprofit center housed under the North American Coalition for Insect Agriculture, categorizes insect frass as a soil amendment.
Fertilizers feed plants directly with concentrated nutrients for quick growth, while soil amendments act as “conditioners” to improve the soil’s physical properties, which can promote root health and improve microbial activity. Some organic materials like compost serve both functions.
“Typically, these organic sources like insect frass have a much lower nutrient concentration to be considered a fertilizer, but more often they have greater organic material, like carbon, so it also has other benefits associated with increasing organic matter, or the overall soil health,” said Gerson Drescher, an assistant professor of soil fertility in the department of crop, soil and environmental sciences and a co-author of the study.
Given its limited availability and production levels, even at projected annual levels of 5.5 million tons by 2033, frass could likely only be utilized by small-scale farmers, organic production systems or included at lower rates in commercial row crop production as a plant growth promoter instead of a replacement for synthetic fertilizers, Drescher noted.
“Moving forward with the studies we have right now in the field, we’re seeing so many positive results for yields that it’s very exciting,” Amorim said. “The whole goal here is not to replace synthetic fertilizers but explore frass as a potential amendment with some added benefits like reduced leaf damage to reduce pesticide use.”
Insect sustainability
The black soldier fly is a promising commercially important insect species as it can be fed a wide range of agricultural waste and side-streams, yielding protein for animal feed while reducing landfill waste accumulation, according to Keith Driver, sustainability advisor and project director of Ty-Pro, the joint venture between Tyson and Protix.
In 2023, Tyson Foods Inc. announced a partnership with Protix, a global insect ingredient company based in the Netherlands. In addition to its investment, Tyson is working with Protix to build a U.S. facility that will use agri-food waste to feed black soldier flies, which will, in turn, be processed into feed for pets, poultry and fish.
Since black fly larvae can consume food that would be unsafe for human consumption, the partnership is transforming otherwise inedible materials into a cost-effective feed ingredient, keeping food waste out of landfills, out of water treatment plants and off the land, Driver said.
There are nutritional benefits, too. For example, a chicken's natural diet includes insects, and that produces great tasting eggs, Driver said. He spoke about the partnership in December during the Food Matters Honors College Signature Seminar, a course that examines the legal, social and environmental dimensions of the modern food system.
"We see it as an ingredient in the food chain that can unlock animal health, more natural flavors and nutrient-dense foods,” Driver said.
More to learn
Drescher said there is still much to learn about the microbiology and nutrient release dynamics of insect frass as a soil amendment and how it works for other row crops.
For example, in the study, both the low and high frass rates increased soil nitrate nitrogen levels in non-irrigated systems relative to unfertilized control but did not differ from poultry litter. Conversely, in irrigated soybean systems, poultry litter plots had 37 percent less soil nitrate nitrogen than frass treatments and the unfertilized control.
Co-authors of the study, titled “Recycling waste via insect agriculture: Frass impacts on soil and plant health,” included Thomas Ducey, a Research Microbiologist with the USDA-ARS; Valerie Brewer-Gunsaulis, associate director of research development, Alana Patterson, a food scientist, and Giovanna De Blasis, senior food scientist, with Ty-Pro Inc.; Phillip Owens, research leader and research soil scientist with the USDA-ARS’s Dale Bumpers Small Farms Research Center in Booneville; and Iris van Straaten, formerly with Protix B.V.
To learn more about ag and food research in Arkansas, visit aaes.uada.edu. Follow the Arkansas Agricultural Experiment Station on LinkedIn and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.
About the Division of Agriculture
The University of Arkansas System Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.
The Division of Agriculture is one of 20 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on three system campuses.
Pursuant to 7 CFR § 15.3, the University of Arkansas System Division of Agriculture offers all its Extension and Research programs and services (including employment) without regard to race, color, sex, national origin, religion, age, disability, marital or veteran status, genetic information, sexual preference, pregnancy or any other legally protected status, and is an equal opportunity institution.
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Media Contact:
John Lovett
U of A System Division of Agriculture
Arkansas Agricultural Experiment Station
(479) 763-5929
jlovett@uada.edu