Use of Orchard Debris for Vermifiltration: Advancing Regenerative Agriculture and Wastewater Treatment

Purpose

This study assesses the economic and air quality benefits of using chipped apple orchard wood as a carbon source in a vermifiltration wastewater system. Instead of burning orchard debris, which releases harmful pollutants, the Perca system repurposes it as a substrate for earthworm-microbial wastewater treatment. The study also compares apple wood chips to traditional conifer chips, evaluating their effectiveness and the broader environmental and economic advantages of diverting orchard waste.

What Did We Do?

Image 1. Chipping process of apple orchard tear-out debris using Morbark, Eeger Beever, 1621” x 18”x 20.5” feeder throat with 140 horsepower motor.

Apple orchard tear-out debris from a local orchard was collected, chipped, and transported for installation as a substrate for the Perca vermifiltration system. Debris was screened to remove foreign materials, chipped to less than ½ inch size, and weighed to calculate tons of usable wood per ton of orchard debris. Data from processing, including chipping costs and labor requirements, were used to assess economic feasibility and air quality impact. In addition, a bench-scale test was conducted to evaluate the efficacy of wastewater treatment by apple orchard chips when compared to the standard conifer chips used in the Perca vermifiltration system. Removal efficiencies of total suspended solids (TSS), biological oxygen demand (BOD), and polychlorinated biphenyls (PCBs) were measured for both substrates.

Image 2. Example of foreign objects (wire) embedded in apple wood pieces.

Market projections for Perca’s vermifiltration system show a compound annual growth rate (CAGR) of 113.45%, reaching 9.57% of the market over the next five years. Calculated market projection estimates over 16,000 tons of orchard debris could be converted into a value-added substrate product rather than burning. This shift could eliminate more than 500 tons of emissions between 2025 and 2029. Economic analysis shows that while chipping costs and wood size restrictions pose challenges for trellised orchards, non-trellised orchards offer better yields and lower costs, with market trends and technology advancements pointing toward broader economic feasibility. Bench-scale tests showed that both apple wood and conifer substrates effectively reduced TSS, BOD, and PCBs by more than 80% in all categories with no significant difference in performance, confirming apple debris works as well as conifer media. These findings demonstrate that apple orchard debris provides an environmentally sustainable alternative to burning, thus contributing to improved air quality, while also an efficient, cost-effective vermifiltration substrate for wastewater treatment.

Image 3. Pine media and apple orchard tear-out fines.

Image 4. Rapid Assay Vermifiltration System (RAVS) used to test wastewater contaminant removal capability in traditional (pine) media and apple orchard tear-out fines.

Future Plans

Ongoing efforts focus on refining the use of apple orchard debris to create a cost-effective, reliable wood chip that matches or exceeds current substrates in reducing conventional and nonconventional wastewater pollutants, while offering an economic alternative to burning. Additionally, strategies are being developed to integrate vermifiltration into regenerative agriculture and circular bioeconomy practices by repurposing spent substrate as a nutrient-rich soil amendment or for soil remediation. This approach transforms agricultural waste into multiple value-added resources, supporting both environmental sustainability and economic viability through continued innovation, collaboration, and stakeholder engagement.

Authors

Presenting & Corresponding author

Sierra J. Smith, Director of Research and Development, Perca, Inc., sierrasmith@perca.net

Additional authors

Joseph S. Neibergs, Professor Extension Economist and Director Western Center for Risk Management Education, Washington State University

George A. Damoff, Chief Science Officer, Perca, Inc.

David A. Elmenhurst, Chief Financial Officer, Perca, Inc.

Additional Information

perca.net

https://ecology.wa.gov/about-us/accountability-transparency/partnerships-committees/boards-councils/agricultural-burning-research-task-force

Acknowledgements

Washington State Department of Ecology for funding and support

Washington State Agricultural Burning Practices & Research Task Force, under direction of the Department of Ecology, for funding and support

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

April 2, 2025May 11, 2025

Reducing Ammonia Emissions from Poultry Litter with Lignite and Lignosulfonate

Due to a technical glitch, we did not get this presentation recorded. Please accept our apologies.

Purpose

The purpose of this study was to determine the effectiveness of lignite, a low-quality coal, and lignosulfonate, a byproduct of paper milling, in reducing ammonia emissions from poultry litter.

What Did We Do?

We utilized a laboratory

acid-trap chamber system to assess the effectiveness of varying rates of lignite and lignosulfonate on ammonia reduction when compared to an industry standard, sodium bisulfate (PLT), and an untreated control. In the volatilization experiment, 12 treatments were tested, including five application rates of lignite and lignosulfonate (0.75, 1.5, 3, 4.5, and 6 kg m-2), PLT, and an untreated control. Acid traps of 0.02 M phosphoric acid were changed 11 times over the 14-day experiment. Acid trap solutions were then analyzed for ammonia to quantify cumulative ammonia emissions.

What Have We Learned?

Both lignite and lignosulfonate were effective in reducing ammonia volatilization in this laboratory setting. While both lignite and lignosulfonate required higher application rates to achieve the same ammonia reduction as PLT, these could be effective alternatives and should be further studied on a larger scale.

Future Plans

While we have no active plans to continue this work, future efforts should include small scale testing in a commercial setting, cost analysis, and sourcing options.

Authors

Presenting & Corresponding author

Stephanie Kulesza, Assistant Professor, North Carolina State University, sbkulesz@nscu.edu

Additional Information

This research is not yet published. Reach out to Stephanie Kulesza at sbkulesz@ncsu.edu if you would like to know more about this work.

April 2, 2025

Consumer Demand for products using biochar

Purpose

This research aims to analyze consumer sentiment and demand for biochar-enriched products, with a focus on their willingness to pay. By assessing how consumers perceive and value biochar’s environmental and agricultural benefits—such as reduced greenhouse gas emissions, carbon sequestration, improved soil health, enhanced water efficiency, and increased yields—the study explores how these factors influence purchasing decisions.

Understanding these preferences is essential for determining the market viability of biochar-enriched products and identifying potential price premiums. Additionally, the study provides insights into policy recommendations on eco-labeling, sustainability certifications, and incentives for biochar adoption. As the biochar market is still emerging, these findings will help producers and suppliers assess whether investment in biochar-based systems is financially viable based on consumer demand.

What Did We Do?

For our analysis, we employed the contingent valuation method (CVM), a widely used approach in consumer studies. In this method, consumers are asked whether they are willing to pay a premium for products after being informed about their environmental and health benefits compared to conventional options. Our analysis is based on the premise that consumers care about the products they purchase, particularly in terms of the environmental and health benefits they offer.

To capture a broad range of consumer sentiments, the survey was designed to gather data from approximately 1,006 U.S. respondents aged 18 and older who consume meat, selected randomly through Qualtrics. The sample was evenly balanced, with 50.4% female and the remaining respondent’s male. The survey aimed to understand meat consumers’ preferences regarding sustainably produced feed, particularly focusing on corn silage produced using biochar. It collected demographic information and insights into participants’ meat purchasing habits, such as the frequency of purchases and their preferred locations. Participants ranked factors like taste, price, health benefits, environmental impact, and brand when selecting meat products. We also assessed their awareness of sustainable agriculture practices, environmental claims, and the effects of traditional farming.

Since biochar is a relatively new concept, respondents unfamiliar with biochar were shown an educational video explaining its benefits as a soil amendment. Respondents were then asked to choose between sustainable feed and conventional feed, as well as to rank the importance of sustainable feed sources in meat production. Following this, respondents listing benefits of biochar in silage production, including reduced greenhouse gas emissions, reduced water usage, decreased chemical fertilizer use, reduced carbon footprint, and improved soil health. Finally, respondents were asked about their willingness to pay a premium for meat produced with sustainably raised feed (silage produced using biochar) and whether additional product information or certifications, such as USDA , Organic, would influence their purchasing decisions.

What Have We Learned?

From our survey, we learned that demographic factors such as marital status, education level, urban residence, and full-time employment are associated with greater concern for health and a willingness to pay a premium for higher-quality meat. Nearly 94% of participants purchased meat from supermarkets, with 66% doing so weekly, with taste and price being the most important factors in their decision-making. Health benefits were considered, but they were secondary to taste and price. Environmental sustainability and brand identity had a minimal influence on purchasing choices, and most consumers did not actively seek information about food production processes. A significant portion of respondents, particularly those unfamiliar with sustainable farming practices, did not let environmental claims impact their meat purchases.

Additionally, our findings revealed that over 92% of respondents were initially unaware of biochar and its benefits. However, after being exposed to an informational clip, 49% expressed interest in learning more about biochar, and 35% felt informed enough to make a purchasing decision. Participants recognized key benefits of biochar, including reduced chemical fertilizer use, lower water consumption, and improved soil health. By the end of the survey, more than 69% of respondents indicated a willingness to pay a premium for sustainably raised meat.

Moreover, familiarity with sustainable agriculture and consideration of environmental claims played a significant role in purchasing decisions, emphasizing the impact of awareness on consumer behavior. Certification and detailed product information, both of which were statistically significant at the 1% level, further enhanced consumer trust and perceived value, increasing the likelihood of premium pricing acceptance.

Future Plans

The analyses conducted thus far are based on survey results, utilizing descriptive statistics and an ordered logit regression model. Moving forward, we plan to apply these findings to estimate market demand for biochar-based products and compare the profitability of biochar-based production with conventional practices. This expanded analysis will offer deeper insights into consumer preferences, the potential price premium for biochar products, and the economic viability of integrating biochar into agricultural production systems.

Authors

Presenting & Corresponding author

Sunita Bandane Pahari, Graduate Research Assistant, University of Idaho, paha0494@vandals.uidaho.edu

Additional author

Jason Winfree, Professor, University of Idaho

Additional Information

Idaho Sustainable Agriculture Initiative for Dairy (ISAID)

This informational clip derived from You Tube is used for survey to provide information on what is biochar and its benefits to participants: https://youtu.be/7qVcEvKEfGc?si=Isxex7E4lJCQrfGc

Acknowledgements

This research was funded by the USDA Sustainable Agricultural Systems Initiative through the Idaho Sustainable Agriculture Initiative for Dairy (ISAID) grant (Award No. 2020-69012-31871).

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7-11, 2025. URL of this page. Accessed on: today’s date.

April 2, 2025

Impacts of Swine Manure Application on Soil Properties in Continuous Corn Plot

Purpose

Land application of swine manure (SM) offers a practical approach to supplying nutrients to crop fields while enhancing soil organic carbon and micronutrient contents. This study is a part of a multi-state project evaluating the effects of SM land application on soil properties and corn yield in comparison to inorganic fertilizer (IF).

What Did We Do?

The experiment is conducted on a five-acre plot using randomized complete block design, consisting of three treatments [IF, SM, and SM+ Starter Fertilizer (SF)], over five years. The study aims to measure various soil properties (organic carbon, nitrogen content, bulk density, porosity, water holding capacity, soil respiration, pH, electrical conductivity, and soil macro- and micronutrient contents). Soil samples are collected from each plot at various depths (0-3, 3-6, 6-12,12-18, 18-24, 24-36 inches) to evaluate treatment effects over time.

What Have We Learned?

Although the study is still in its early stages, preliminary data show promising results for corn yield in the first year, with 144.96, 174.09, and 168.39 bushels per acre for the IF, SM and SM+SF treatments, respectively. While the differences were statistically non-significant (p = 0.32), the SM treatment achieved the highest yield. Soil compaction (measured using SHT-003 Soil Load Penetrometer) of the field was non-significant (p = 0.56) for the treatments. However, the highest soil compaction was observed with the inorganic fertilizer (11.86 Newton) treatment, followed by SM (11.07 Newton), and the lowest soil compaction with the SM + SF (10.99 Newton) treatment. These findings suggest that swine manure may have a positive impact on the corn yield and soil compaction.

Figure 1: Effects of SM, IF & SM+IF applications on corn yield(SM- Swine Manure, IF- Inorganic fertilizer, SM+SF: Swine manure + Starter Fertilizer)

(Data are presented as mean with standard error, bars with different letters denote significantly different at p<0.05) — Figure 1: Effects of SM, IF & SM+IF applications on corn yield
(SM- Swine Manure, IF- Inorganic fertilizer, SM+SF: Swine manure + Starter Fertilizer)
(Data are presented as mean with standard error, bars with different letters denote significantly different at p<0.05)

Furthermore, we observed significant differences (p < 0.05) in Soil Plant Analysis Development (SPAD, chlorophyll and nitrogen contents in leaves measured using Minolta Chlorophyll Meter) values among the treatments, with IF showing the highest value (52.37), followed by SM (48.15) and then the SM+SF (45.56).

Figure 2: Effects of SM, IF & SM+IF application on SPAD values(SM- Swine Manure, IF- Inorganic fertilizer, SM+SF: Swine manure + Starter Fertilizer, SPAD- Soil Plant Analysis Development)

(Data are presented as mean with standard error, bars with different letters denote significantly different at p<0.05) — Figure 2: Effects of SM, IF & SM+IF application on SPAD values
(SM- Swine Manure, IF- Inorganic fertilizer, SM+SF: Swine manure + Starter Fertilizer, SPAD- Soil Plant Analysis Development)
(Data are presented as mean with standard error, bars with different letters denote significantly different at p<0.05)

The electrical conductivity (measured using Hanna GroLine Soil EC Tester) of the soil was significantly influenced (p < 0.05) by the treatments. The highest electrical conductivity was observed with the application of SM (0.36) which is statistically similar to SM+SF (0.32) treatment, but significantly higher than the IF (0.22) treatment.

Fig. 3 Effects of SM, IF & SM+IF application on electrical conductivity (EC)(SM- Swine Manure, IF- Inorganic fertilizer, SM+SF: Swine manure + Starter Fertilizer, EC- Electrical Conductivity)

(Data are presented as mean with standard error, bars with different letters denote significantly different at p<0.05) — Fig. 3 Effects of SM, IF & SM+IF application on electrical conductivity (EC)
(SM- Swine Manure, IF- Inorganic fertilizer, SM+SF: Swine manure + Starter Fertilizer, EC- Electrical Conductivity)
(Data are presented as mean with standard error, bars with different letters denote significantly different at p<0.05)

Future Plans

We plan to take the growth parameters including plant height and chlorophyll content (SPAD) at regular intervals. Additionally, we intend to sample soil microbiome composition in the field. This year we harvested 6 rows per plot but starting next year, we will harvest 18 center rows per plot (out of 31) for yield measurement. We will also exclude 15 feet from both the northern and southern ends of each plot.

Authors

Presenting author

Ravi Raj Mishra, Graduate student, University of Missouri, Columbia

Corresponding author

Teng-Teeh Lim, Extension Professor, University of Missouri, Columbia, limt@missouri.edu

Additional author(s) (name, title, and affiliation for each)

Manobendro Sarker, Graduate student, University of Missouri, Columbia

Keywords

Swine Manure, Soil Health, Soil Properties, Starter Fertilizers

Acknowledgements

We acknowledge the National Pork Board for the funding and collaboration with South Dakota State University. Our sincere thanks also go to Manobendro Sarker, Moh Moh Thant Zin, and Rana Das from our research group, and the research farm team for their support in field operations.

April 2, 2025

Effects of manure land application on soil properties based on multiyear state-wide data in Missouri

Purpose

Soil health is crucial for sustainable crop production, which can differ from conventional soil nutrient considerations. Analyzing a multiyear, state-wide dataset can greatly improve the understanding of soil health status. In collaboration with the Missouri N340 cover crop cost-share program, this research compiled multiyear soil sample results from fields throughout Missouri and assessed the effects of manure application strategies on soil properties.

What Did We Do?

A total of 14,473 soil samples were collected from 2015 to 2022 across Missouri. The physicochemical properties of soil samples were analyzed by the University Soil Health Assessment Center (SHAC). To evaluate the impacts of manure application, results were first compared with fields that received inorganic fertilizer, followed by the interaction with soil texture. The effects of manure type and their application method were further studied in this research.

What Have We Learned?

In most years, manure application increased potentially mineralizable nitrogen (PMN), Bray-1 phosphorus (P), permanganate-oxidizable carbon (POXC), and organic carbon, showing more significant differences in some years compared to inorganic fertilizer. There was no improvement in effective cation exchange capacity (ECEC), but aggregate stability was highly variable for manure application (Figure 1).

Figure 1: Effects of manure land application on soil properties for soil samples of 2015-2022 (M- Manure, IF- Inorganic fertilizer; significant codes: *** : < 0.001, ** : < 0.01, * : <0.05)

The interaction between manure and soil texture significantly (p<0.01) affected PMN, ECEC, organic carbon, and POXC, but no significant difference in aggregate stability was observed. There was also a significant effect of manure type on ECEC and organic carbon, as shown in Figure 2. The organic carbon of fields that received cattle and swine manure was significantly higher (p<0.05) than poultry manure-receiving fields, but there was no significant difference between cattle and swine manure.

Figure 2: Effects of manure types on soil physicochemical properties (Data are presented as mean with standard error, bars with different letters denote significantly different at p<0.05)

In Missouri, surface application is the most commonly used application method, followed by incorporation and injection. Figure 3 illustrates the effects of different manure application methods on soil properties. There was no significant difference in PMN and Bray-1 P across the application methods. However, the application method significantly affected ECEC and organic carbon, which were higher for manure injection. Surprisingly, the aggregate stability was the lowest for fields with manure injection.

Figure 3: Effects of manure application methods on soil properties (Data are presented as mean with standard error, bars with different letters denote significantly different at p<0.05)

Future Plans

Data from management practices reveals notable variations in manure types and application rates across the state. Additionally, many farms have adopted cover crop practices and mixed tillage methods, including no-till, reduced tillage, and conventional tillage. Given the diversity of agricultural practices in Missouri, data collection and analysis are ongoing, with a field experiment at a university farm currently underway to provide further insights and validation.

Authors

Presenting author

Manobendro Sarker, Graduate student, University of Missouri, Columbia

Corresponding author

Teng-Teeh Lim, Extension Professor, University of Missouri, Columbia, limt@missouri.edu

Additional authors

Morgan Davis, Assistant Professor, University of Missouri, Columbia

Donna Brandt, Lead Research Specialist, Soil Health Assessment Center, University of Missouri, Columbia

Timothy Reinbott, Director, Field Operations, Agricultural Experiment Station

University of Missouri, Columbia

Additional Information

Please email us at limt@missouri.edu (Teng-Teeh Lim) or ms59d@umsystem.edu (Manobendro Sarker).

Acknowledgements

We gratefully acknowledge the Missouri Department of Natural Resources, Soil and Water Conservation Program for funding the project. We also thank Moh Moh Thant Zin, Rana Das, and Ravi Mishra from our research group for their assistance with field operations.

April 2, 2025

Advanced Multi-Stage Wastewater Treatment for Sustainable Dairy Farm Management

Purpose

Dairy farms employing flushing systems often encounter significant challenges in managing substantial volumes of recycled water, which can have environmental, economic, and operational implications. This study aims to evaluate a multi-stage process designed to improve solid/nutrient extraction from flushed water already treated by a pull-plug sediment basin system.

What Did We Do?

We implemented a three-stage sequential treatment process comprising coagulation, Fenton oxidation, and membrane filtration. In the first stage, coagulation was performed using aluminum sulfate (Al₂(SO₄)₃) to remove colloidal solids from the treated barn flushing water. The optimal alum dosage (500–7,000 mg/L) was determined based on turbidity, total solids, and chemical oxygen demand (COD) removal.

The second stage involved Fenton oxidation, where hydroxyl radicals generated from hydrogen peroxide (H₂O₂) and an iron catalyst (Fe²⁺) further degraded organic pollutants. Utilizing response surface methodology (RSM), we optimized the concentrations of H₂O₂ (500–1,800 mg/L), FeCl₃ (250–950 mg/L), and reaction time (15–50 min) to achieve a balance between treatment effectiveness and cost efficiency.

In the final stage, ultrafiltration and reverse osmosis were employed to remove dissolved ions, ensuring compliance with discharge standards.

What Have We Learned?

Fig. 1. Removals of turbidity (a), total solid (b), COD (c), and impacts on pH (d) at various alum treatment concentrations.

The results indicated that turbidity removal peaked at a dosage of 5,000 mg/L of Al₂(SO₄)₃, while total solids and COD removal stabilized at 4,000 and 5,000 mg/L, respectively. Although turbidity initially increased following the coagulant addition, the formation of aluminum hydroxide flocs facilitated effective pollutant removal. To balance reagent costs and treatment efficiency, a dosage of 4,000 mg/L alum was selected. After coagulation, the coagulated supernatant underwent fenton oxidation.

Turbidity removal (%)

Fig. 2. The removal of turbidity (%) at the interactions between H2O2 and FeCl3 (a), between H2O2 and time (b), and between FeCl3 and time (c). — Fig. 2. The removal of turbidity (%) at the interactions between H₂O₂ and FeCl₃ (a), between H₂O₂ and time (b), and between FeCl₃ and time (c).

Response surface analysis confirmed that optimal turbidity removal was achieved with H₂O₂ concentrations of 1,280-1,800 mg/L and FeCl₃ concentrations of 550-950 mg/L. Furthermore, a minimum mixing of 36 minutes was necessary to attain maximum efficiency.

Total solid removal (%)

Fig. 3. The removal of total solid (%) at the interactions between H2O2 and FeCl3 (a), between H2O2 and time (b), and between FeCl3 and time (c). — Fig. 3. The removal of total solid (%) at the interactions between H₂O₂ and FeCl₃ (a), between H₂O₂ and time (b), and between FeCl₃ and time (c).

For total solids removal, effective interaction was observed at H₂O₂ levels of 500–1,240 mg/L and FeCl₃ concentrations of 250–450 mg/L. Mixing times exceeding 43 minutes were found to reduce removal efficiency.

COD removal (%)

Fig. 4. The removal of COD (%) at the interactions between H2O2 and FeCl3 (a), between H2O2 and time (b), and between FeCl3 and time (c). — Fig. 4. The removal of COD (%) at the interactions between H₂O₂ and FeCl₃ (a), between H₂O₂ and time (b), and between FeCl₃ and time (c).

COD removal was most effective within the H₂O₂ range of 500–760 mg/L and FeCl₃ concentrations of 450–950 mg/L, while mixing time had minimal impact.

Cost ($)

Regarding treatment cost, H₂O₂ was identified as the most influential cost factor due to its higher price. To balance removal efficiency and cost, the optimized conditions were determined as 563.3 mg/L H₂O₂, 568.4 mg/L FeCl₃, and a 33-minute reaction time, according to the calculations of RSM model. This setup achieved 86.4% turbidity removal, 18.7% total solids removal, and 81.5% COD removal at a treatment cost of $0.03 per liter of wastewater.

Future Plans

The next phase of the study will focus on membrane filtration experiments to further remove dissolved ions and ensure compliance with discharge standards. Additionally, a systematic economic analysis will assess cost-effectiveness, scalability, and operational feasibility for large-scale dairy farm applications.

Authors

Presenting author

Moh Moh Thant Zin, Post-doctoral researcher, University of Missouri-Columbia

Corresponding author

Teng-Teeh Lim, Extension Professor, University of Missouri-Columbia, limt@missouri.edu

Acknowledgements

Funding is provided by USDA-NIFA, grant award (2018-68011-28691) and University of Missouri Extension.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7-11, 2025. URL of this page. Accessed on: today’s date.

April 2, 2025

Application of Sonar Depth Finder in Lagoon Sludge Survey

Purpose

Regular monitoring of lagoon depths is crucial for effective manure management and environmental compliance. Traditional methods, using a disc on a rope or a marked stick from a boat can be time-consuming and pose safety risks, especially in larger or deeper lagoons. This study aimed to determine the feasibility of using low-cost sonar depth finders for lagoon sludge measurement.

What Did We Do?

Depth measurements were conducted by using sonar devices and compared with traditional methods at a 2.5-acre dairy lagoon that received effluent from a pull-plug sediment basin. The sonar devices, along with a cell phone (data logger) were mounted on an air-filled float and dragged across lagoon surface, enabling measurements without the need for a boat.

Fig. 1. Lagoon depth measurement was conducted using a small kayak (left); practical and simple lagoon depth measurement by dragging air-filled float with sonar ball and cellphone (as data logger) across lagoon surface (right).

Fig. 2. Field measurement points on the lagoon surface for the liquid depth measurement using disc on a rope and a sonar ball sensor. The white dots are measurement points to compare sonar ball method and disc on a rope method, the blue lines were measurement paths dragging a small air-filled float carrying sonar ball

What Have We Learned?

Fig. 3. Liquid depth measurement devices applied: disk on a rope (left), wood stick with depth markings (middle), and two types of commercial sonar balls (right).

Fig. 4. Comparison of depth measurements using different measurement methods.

The disc on a rope (standard) and wood stick method resulted in similar values. Meanwhile, the sonar balls tend to slightly underestimate depth, with a margin of error below 15%, while the errors were higher for very shallow areas.

Fig. 5. Linear regression of depths, comparing the Deeper Sonar PRO+ and Deeper Fishfinder START, with disc on a rope values.

Linear regression models revealed strong correlations between sonar readings and the disc-on-a-rope method, with R² values of 0.899 for the PRO+ model, and 0.9377 for the START model. Applying a correction model to the sonar data could further enhance the measurement accuracy. This study demonstrated that integrating sonar measurements with periodic sludge sampling provides a practical, safe, and reliable approach to improving lagoon management.

Authors

Presenting author

Moh Moh Thant Zin, Post-doctoral researcher, University of Missouri-Columbia

Corresponding author

Teng-Teeh Lim, Extension Professor, University of Missouri-Columbia, limt@missouri.edu

Additional author(s)

Zonggang Li, Gilbert Mitto, Manobendro Sarker, Rana Das, Cuong Duong, University of Missouri-Columbia.

Acknowledgements

This research was supported by USDA-NIFA, grant award (# 2018-68011-28691), and University of Missouri Extension.

April 2, 2025April 2, 2025

Optimizing stoichiometry in Cover Crops to Boost Soil Health and Enhance Carbon Sequestration

Purpose

Increasing the quantity of carbon (C) inputs is a pathway to build soil C stores. One way to achieve this is using cover crop mixtures which can increase the amount and types of root exudates, supporting greater microbial activity and biomass. However, few studies use stoichiometry i.e., C:Nitrogen (N) ratios (the amount of C in relation to the amount of N present) to select cover crop mixes. Our major objective is to understand plant-soil feedback in the context of the legacy effects of cover crop stoichiometry on soil health, C-sequestration, and crop yields. We hypothesized that cover crops with a lower C:N ratio will increase nitrogen availability for the next crop cycle and increase C-sequestration.

What Did We Do?

We are conducting a multi-year, random-block field experiment comparing cover crop mixtures with low, medium-low, medium-high, and high C:N ratios (Table 1), and a fallow control (n=5). We are also interested in the effect of cover crop termination (herbicide vs. roller-crimper) on subsequent barley cash crop. The experiment was established in Southern Idaho, at the Kimberly Research and Extension Center. Soil samples were taken at the start of the experiment in fall 2023, spring, and fall 2024 to compare cover crop effects on soil health.

Table 1. Treatments implemented in this study

“Soil health is the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals and humans, and connects agricultural and soil science to policy, stakeholder needs and sustainable supply-chain management” (Lehmann, et al. 2020). Moreover, natural or anthropogenic actions can change soil properties rapidly. It makes these properties be considered as good soil health indicators, that can be physical, chemical and biological. The first two have a slow response compared to the microbiological and biochemical properties.

The soil health properties evaluated in this research are:

*Physical properties: water holding capacity (the amount of water that a soil can retain).

*Chemical properties: pH, soil organic matter (decayed material that originated from a living organism), nutrient analysis (NH4-N, NO3-N, PO4, major ways that nutrients can be taken by plants).

*Biological properties: enzyme activities involved in the main biogeochemical cycles mineralizing organic matter (α- and β- glucosidase, cellobiosidase, acid and alkaline phosphatase, leucine aminopeptidase, N-acetyl-glycosaminidase), substrate induce respiration (response of microbial respiration to the addition of a nutrient as glucose), carbon mineralization (process for capturing, storing, and utilizing CO2 to synthesize other products). Also, we included agronomic parameters such as yield, crop biomass, full and empty grain.

Statistical analysis was conducted using R software version 4.4.0. Evaluating these attributes allow to verify the soil status and apply better management to get a desire outcome, e.g. increase organic matter in soil.

What Have We Learned?

Overall, the results in the first year of the study showed that medium-high C:N ratio treatment has the potential to improve soil health (Fig. 1), while herbicide termination performed better in comparison to roller crimper termination treatment.

The preliminary results show among all treatments an increase in moisture and pH with a decrease in water holding capacity during the spring compared with the fall seasons compared to fallow treatment. Active microbial biomass (i.e., substrate-induced respiration) did not differ between treatments for fall 2023 and spring 2024; however, carbon and nitrogen mineralization was higher before the treatments were established. Additionally, phosphorous did not vary across time.

Fig. 1. Potential nitrification rates in soil samples under cultivation with different C:N stoichiometry of cover crops. Lowercase letters above columns indicate differences at P < 0.05

Agronomic parameters showed that herbicide termination method gave more barley height, dry aboveground biomass, seed counts, grain weight, total full grain, and barley yield (Fig. 2). On the other hand, the roller crimper termination method increased the amount of empty grain and the presence of weeds in the field.

Fig. 2. Barley yield in 2024 following different cover crops based on their C:N stoichiometry. Lowercase letters above columns indicate differences at P < 0.05

Future Plans

To understand if the environmental condition has a positive or negative influence in soil health parameters, we replicate it at the Plant Materials Center (NRCS, USDA, Pullman, WA) where the environmental conditions are distinct from those in Southern Idaho. Also, we plan to conduct two more years of the experiment. We expect that the information obtained at the end of the study can provide fundamental information to the research community and guide farmers in the selection of cover crops and the termination methods for them in different environmental conditions.

Authors

Presenting authors

Vanessa Otero Jiménez, Postdoctoral Fellow, University of Idaho

Linda Schott, Assistant Professor and Extension Specialist, University of Idaho

Michael Strickland, Research Associated Professor, University of Idaho

Corresponding author

Vanessa Otero Jiménez, Postdoctoral Fellow, Soil and Water System Department, University of Idaho, Vanessao@uidaho.edu

Additional author

Steven Lee, Plant Materials Center, Natural Resources Conservation Service, United States Department of Agriculture

Acknowledgements

This work is supported by grant no. 2021-09118-1027664 from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

April 2, 2025May 11, 2025

N2 Applied: A Novel Approach to Increasing Nitrogen in Animal Manure

Due to a technical glitch, the beginning of the recorded presentation was not recorded. Please accept our apologies.

Purpose

Manure management technologies are constantly being developed. But do these technologies meet their intended purpose? How effectively do they perform? Providing impartial evaluations on the effectiveness and longevity of these technologies requires time, finances, and expertise.

Newtrient, with support from a Natural Resources Conservation Service (NRCS) Conservation Innovation Grant (CIG) and a New York Farm Viability Institute Grant, has been evaluating 15 manure-related technologies with a focus on water quality. Through this effort, Newtrient will document the findings from each study to promote the broader adoption of these technologies in livestock manure management. One of the technologies evaluated, N2 Applied, explored the use of plasma treatment to increase nitrogen content in the manure waste stream, while simultaneously reducing ammonia and greenhouse emissions. This presentation will primarily highlight the results from the N2 Applied evaluation.

Figure 1. N2 Applied Demonstration Unit.

What Did We Do?

Newtrient collaborated with Washington State University to develop a technology review protocol. This evaluation process was modeled after the NRCS approach for assessing Waste (Manure) Treatment technologies, as outlined in Conservation Practice Standard 629, Waste Treatment. One of the challenges in reviewing manure management technologies has been obtaining technical third-party evaluations. This protocol established a comprehensive method for reviewing and evaluating these technologies.

For the N2 Applied system, Newtrient contracted with Cornell University as the third-party evaluator. This evaluation compared the nitrogen content and stability of untreated and treated dairy manure over a 15-week period. Both static and flow-through tanks were studied to assess the effectiveness of this treatment process. Liquid samples were analyzed for nutrient content, with a focus on water quality issues, and a limited number of air samples were collected to evaluate greenhouse gas emissions and air quality.

The N2 Applied plasma technology uses electricity to split atmospheric nitrogen and oxygen which then forms into reactive nitrogen gas. This gas is absorbed into the manure waste stream raising the amount of plant available nitrogen while also lowering the pH. This demonstration unit was delivered and operated from a 20 feet long cargo bin.

Figure 2. Static and Flow Through Tanks Utilized for Technology Evaluation.

What Have We Learned?

The N2 Applied technology increased the nitrogen content of the dairy manure by more than 50% in the static tanks and nearly 50% in the flow-through tanks. The plasma torch created nitrogen oxides by combining atmospheric nitrogen and oxygen gases. This treatment process lowered the pH to a set point, initially set at 5.5 but later adjusted to 5.0. This lower pH inhibited the microbial production of methane (CH4) and converted more of the nitrogen to ammonium (NH4+) instead of the more volatile ammonia (NH3). The following two figures show the impact of the N2 Applied technology on methane and nitrogen stability for the static tank portion of the study.

Figure 3. CH4 from static tanks — Figure 3. CH₄ from static tanks

The nitrogen content remained stable for more than 4 months, and methane production was significantly reduced through this process. Coarse solid/liquid separation was a key component ensuring the efficient operation of the technology.

Figure 4. Nitrogen Levels with and without N2 Applied Technology.

For this demonstration unit, the plasma torch used approximately one-half of the energy consumed. The estimated annual electrical cost to operate this unit was $26,800. With the lessons learned from this evaluation, the new commercial unit will have much lower electrical costs.

Future Plans

The N2 Applied system evaluated for this study was a demonstration unit. Based on the lessons learned, a commercial unit is currently being developed, with deployment to the United States expected in late 2025. Once a new unit is installed, another series of studies will be conducted following a similar testing protocol.

For the commercial unit, a critical factor to evaluate will be the long-term stability of the nitrogen-enriched manure. Additionally, it will be important to assess production rates, along with capital and operating costs. Agronomic trials, combined with field emission measurements, will determine the impact on crop yield and air quality once the product is land applied.

Authors

Presenting & Corresponding author

Jeff Porter, Technical Consultant, Newtrient, jeff.porter@newtrient.com

Additional author

Mark Stoermann, Chief Operating Officer, Newtrient

Additional Information

Project and Vendor Information: 2020 NRCS Conservation Innovation Grant – Newtrient

Acknowledgements

Special thanks to the USDA-NRCS Conservation Innovation Grant program and the New York Farm Viability Institute for providing funding to allow for this technology evaluation to take place.

Videos, Slideshows and other media

Webinar Highlighting Evaluation Results: N2 Applied – Insights and Innovation

Newtrient Solutions Catalog: N2 Applied

N2 Applied Homepage: Home – N2 Applied

GEA Manure Enricher: Produce your own sustainable fertilizer | GEA ProManure E2950

April 2, 2025

Agronomic Effectiveness of Nitrogen and Phosphorus Recovered from Swine Manure

Purpose

New technologies have been developed to extract and recover concentrated nitrogen (N) and phosphorus (P) from animal manure which can be upcycled as substitutes for conventional nitrogen (Urea) and triple super phosphate (TSP) fertilizers. In this study, the effectiveness of recovered nitrogen (RN) and phosphorus (RP) from liquid swine manure were compared with conventional N (CN) and conventional P (CP). Further, the availibility of RP to crop was enhanced using acidification of the material.

What Did We Do?

The RN was captured from liquid swine manure using a gas permeable membrane technology (Vanotti and Szogi, 2015). The RP was also captured from liquid swine manure using nitrification followed by chemical precipitation with calcium hydroxide (Vanotti et al., 2005). We evaluated annual ryegrass growth response to conventional and recovered nutrients using four nutrient combinations: CN+CP, RN+CP, CN+RP, and RN+RP at five N rates and three P rates (Figures 1 & 2). In a subsequent experiment, the solubility of RP was modified by acidifying the material before its application.

Figure1. Annual ryegrass N uptake in response to N and P under the different nutrient combinations. CN, conventional nitrogen, CP, conventional phosphorus, RN, recovered nitrogen, RP, recovered phosphorus. (Paye et al., 2024a)

Figure 2. Annual ryegrass P uptake in response to N and P applications under the different nutrient combinations. CN, conventional nitrogen, CP, conventional phosphorus, RN, recovered nitrogen, RP, recovered phosphorus. (Paye et al., 2024a)

What Have We Learned?

The experimental soil was deficient in N and P, thus, the ryegrass responded to application of both nutrients. The ryegrass N uptake under RN was similar to N uptake under CN when using CP (Figure 1). When RN was blended with RP, the N uptake was significantly greater than the N uptake of conventional (CN+CP) nutrients blend. The P uptake of CP was greater than RP when using CN. However, the P uptake of RP blended with RN was substantially greater than CN+CP (Figure 2). The Acidification of RP improved its solubility and agronomic effectiveness (Paye et al., 2024b). Ryegrass supplied with acidified RP produced 8 – 38% greater dry matter yield and had 48 – 72% greater P uptake than ryegrass supplied with CP or non-acidified RP. The greater overall biomass yield and nutrient uptake of the recovered N and P combination demonstrate this as a novel nutrient combination that could be critical for improving crop yield and nutrient use efficiency in a circular agricultural system.

Future Plans

Crop response to these recovered nutrient blends will be evaluated using other crops under both greenhouse and field conditions.

Authors

Presenting & Corresponding Author

Wooiklee S. Paye, Research Soil Scientist, USDA-ARS Coastal Plains Soil, Water and Plant Research Center, Florence, SC, wooiklee.paye@usda.gov

Additional authors

Raul Moral, Professor, Miguel Hernandez University, Orihuela, 03312 Alicante, Spain.

Matias B. Vanotti and Ariel A. Szogi, Research Soil Scientists, USDA-ARS Coastal Plains Soil, Water and Plant Research Center, Florence, SC 29501 USA.

Quentin D. Read, Statistician, USDA-ARS Southeast Area, 840 Oval Drive, Raleigh, NC 27606 USA.

Additional Information

Paye, W. S., Herrero, R. M. Vanotti, M. B., Szogi, A. A., & Read, Q.D. (2024a). Agronomic Effectiveness of Nitrogen and Phosphorus Recovered from Swine Manure. Agrosystems, Geosciences and Environment. (In Press).

Paye, W. S., Vanotti, M. B., Szogi, A. A., & Herrero, R. M. (2024b). Enhancing the Agronomic Efficiency of Calcium Phosphate Recovered from Swine Manure. In ASA, CSSA, SSSA International Annual Meeting. ASA-CSSA-SSSA.

Vanotti, M.B., & Szogi, A.A. (2015). Systems and methods for reducing ammonia emissions from liquid effluents and for recovering the ammonia. U.S. Patent No. 9,005,333 B1, U.S. Patent and Trademark Office.

Vanotti, M.B., Szogi, A.A., & Hunt, P.G. (2005). Wastewater treatment system. U.S. Patent No. 6,893,567, U.S. Patent and Trademark Office.

Acknowledgements

This research was part of USDA-ARS National Programs 212 Soil and Air, ARS Project 6082-12630-001-00D. Raul Moral’s scientific visit to USDA-ARS Florence, SC, was funded by the Government of Spain, Ministry of Science & Innovation, through Fellowship Award PRX21/002116. The authors are thankful to Paul Shumaker and William Brigman for greenhouse and laboratory assistance. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.