Tag: phosphorus

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Comparison of Sulfuric vs. Oxalic Sulfuric When Forming Struvite from Liquid Dairy Manure

Purpose

The purpose of this project was to demonstrate a mobile fluidized-bed cone for extraction of phosphorus in the form of struvite (magnesium-ammonium phosphate) from undigested (raw) liquid dairy manure. Since Ca binds inorganic P, a particular emphasis was placed on evaluating the effect of oxalic acid as an acidifier and Ca binder.

Dairies often have excess P in manure in relation to the need for on-farm crop production. Easily mineable reserves of phosphorus (P) worldwide are limited, with a majority residing in Morocco (USGS 2013). One approach to recycling P is to capture excess P from dairy manure in the form of struvite for off-farm export as a nutrient source for crop production.

What we did

A portable trailer-mounted fluidized-bed cone (volume of 3200 L) was used to extract phosphorus in the form of struvite (magnesium-ammonium phosphate) from undigested (raw) liquid dairy manure. Batches of 13,000 liters of manure were evaluated and the system was operated at a flow rate of ~ 32 liters per minute.  Sulfuric acid or oxalic acid-sulfuric acid were used to decrease the pH, and sodium hydroxide was used to raise the pH. Oxalic acid was chosen for evaluation due to its dual ability to decrease pH and bind calcium.

What we learned

Results of concentration of total P or ortho-P (OP) after manure treatment through the fluidized bed suggested no advantage of the combination of oxalic acid with sulfuric acid to decrease the concentration of P (see Figures 1 and 2). More detailed analyses of centrifuged post-bed samples of manure effluent indicated that the oxalic acid was binding the free calcium, but the resulting Ca compounds remained suspended in the effluent. Centrifuged manure samples had Ca contents ~23% of un-centrifuged samples when oxalic/sulfuric acid was used as a pH reducer. Centrifuged manure samples had Ca contents ~84% of un-centrifuged samples when sulfuric acid was used as a pH reducer. With raw manure, oxalate does not appear to be beneficial, unless there is a more effective step to drop Ca-oxalate out of suspension, such as centrifuging.

Figure 1. Concentration of OP or P in manure after pre-treatment with oxalic and sulfuric acid.
Figure 1. Concentration of OP or P in manure after pre-treatment with oxalic and sulfuric acid.

 

Figure 2. Concentration of OP or P in manure after pre-treatment with sulfuric acid.
Figure 2. Concentration of OP or P in manure after pre-treatment with sulfuric acid.

Future Plans

Anaerobically digested (AD) manure will be evaluated with the same set of conditions that were utilized with raw dairy manure to determine potential benefits of using oxalic acid with AD manure.

Authors

Joe Harrison1, Kevin Fullerton1, Elizabeth Whitefield1, and Keith Bowers2.

1Washington State University

2Multiform Harvest

jhharrison@wsu.edu

Citations and video links

U.S. Geological Survey, Mineral Commodity Summaries, January 2013. http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/mcs-2013-phosp.pdf

The Mobile Struvite Project Overview Video: Capturing Phosphorus from Liquid Dairy Manure and Cost Efficient Nutrient Transport

Dairy Struvite Video: Capturing Phosphorus from Dairy Manure in the Form of Struvite on 30 Dairy Farms in WA state

Alfalfa Struvite Video: Struvite, a Recycled Form of Phosphorus from Dairy Manure, used as Fertilizer for Alfalfa Production

Acknowledgements

This project funded by the USDA NRCS CIG program and the Dairy Farmers of Washington.

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. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

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Comparison of Struvite to Mono-Ammonium-Phosphate as a Phosphorus Source on Commercial Alfalfa Fields

The purpose of this project was to demonstrate a regional nutrient (phosphorus (P)) recycling relationship between the dairy industry and alfalfa forage growers. Dairies often have excess P in manure in relation to the need for crop production on-farm. Easily mineable reserves of phosphorus (P) worldwide are limited, with a majority residing in Morocco (USGS 2013). One approach to recycling P is to capture excess P from dairy manure in the form of struvite for off-farm export for use as a nutrient source of crop production. Washington State produces a significant amount of alfalfa for domestic and international sales.

What did we do

Struvite (Magnesium Ammonium Phosphate – NH4MgPO4· 6H2O) and Mono Ammonium Phosphate (MAP) were applied to 33 and 30 acres (control and treatment, Farm 1); and 60 and 55 acres (control and treatment, Farm 2) sections of alfalfa fields at two commercial forage producers in Eastern Washington. Fertilizer (struvite or MAP) was applied on an equivalent P2O5 basis in August 2017 and September 2018 (Farm 1 – existing stand) and September 2017 and September 2018 (Farm 2 – new seeding).

What have we learned

Accumulative yield of alfalfa in 2018 for Farm 1 was struvite = 7.14 tons, MAP = 7.51 tons. Accumulative yield (2 of 3 cuttings) of alfalfa in 2018 for Farm 2 was struvite = 3.08 tons, MAP = 2.95 tons. Average P concentration of alfalfa in 2018 for Farm 1 was struvite = 0.27, MAP = 0.27 (% DM).  Average P concentration in alfalfa in 2017 for Farm 1 was struvite = 0.31, MAP = 0.32 (% DM). Average P concentration of alfalfa in 2018 for Farm 2 for struvite and MAP was 0.27 and 0.28 % DM, respectively. Average accumulative P uptake of alfalfa in 2018 for Farm 1 was 38 and 39 lbs P/acre for struvite and MAP, respectively. Average accumulative P uptake (2 of 3 cuttings) of alfalfa in 2018 for Farm 2 was struvite = 15 lbs, MAP = 16 lbs P/acre. Results indicate that struvite is equivalent to MAP as a P source for commercial production of alfalfa.

Future Plans

The nutrient recycling project will continue through 2019. In addition, companion replicated plots studies are underway to evaluate the effects of ratio of MAP:Struvite and amount of P application for yield and quality of alfalfa.

Authors

Joe Harrison1, Steve Norberg1, Kevin Fullerton1, Elizabeth Whitefield1, Erin Mackey1, and Keith Bowers2.

1Washington State University, jhharrison@wsu.edu

2Multiform Harvest

Citations and video links

U.S. Geological Survey, Mineral Commodity Summaries, January 2013. http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/mcs-2013-phosp.pdf

    The Mobile Struvite Project Overview Video: Capturing Phosphorus from Liquid Dairy Manure and Cost Efficient Nutrient Transport

    Dairy Struvite Video: Capturing Phosphorus from Dairy Manure in the Form of Struvite on 30 Dairy Farms in WA state

    Alfalfa Struvite Video: Struvite, a Recycled Form of Phosphorus from Dairy Manure, used as Fertilizer for Alfalfa Production

Acknowledgements

This project funded by the USDA NRCS CIG program and the Dairy Farmers of Washington.

 

 

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. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

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Phosphorus contribution from distillers grains to corn and wheat in North Dakota

There is growing interest from farmers to know if distillers grains (DGs) could be used as a cheap alternative or supplemental input for cereal production. Condensed distillers solubles (CDS) and wet distillers grains (WDG) are co-products from ethanol production that are mainly used as sources of feed for livestock. They are sometimes available to farmers when in excess of demands as feed, or when for whatever reason, the plant encounters some storage limitations, and have to dispose of the products. Potential environmental problems and cost of freighting huge loads to distant places for disposal has been a concern for ethanol plants. However, the cost of procurement and transportation of DGs, storage, and availability of appropriate equipment to apply these products to farmlands, are some of the bottlenecks for farmers interested in their value as fertilizer sources. Despite these concerns, farmers who farm in close proximity to ethanol plants, or who have the means to transport and apply these products in nearby fields are the ones likely to benefit from the DGs as fertilizer inputs. Preliminary studies indicate that when DGs are applied to soil as sources of nitrogen (N) or phosphorus (P), yields have been similar or better in comparison to synthetic fertilizers. Farmers also appreciate the environmental value in that nutrients removed with the corn following harvest from their fields to the ethanol plants can be recycled back to farmlands. Procurement of DGs by farmers also creates and enhances a synergism between farmers and the ethanol plants, considering the latter could cut down on storage, drying, or disposal costs if farmers are willing to buy or take any excess DGs.

What Did We Do?

Methods are reported for field studies that assess the effects of P from three sources on grain yield and quality of corn in 2017, and wheat in 2017 and 2018. Study sites were located at the NDSU Carrington Research Extension Center, Carrington (ND). The P sources were CDS, WDG, and triple super phosphate (TSP) fertilizer. Rates of P were 0, 40, and 80 lbs P2O5 for wheat in addition to 120 lbs/ac for corn. Wheat treatments in 2017 and 2018 included surface application versus incorporation following application. The weight or volume of WDG or CDS applied varied by year, depending on the nutrient analysis. In 2018, to apply 20 lbs P, 3.3 T/ac of WDG, and 270 gallons/ac of CDS were required. At these rates, 112 lbs N, 17 lbs S, and 27 lbs K2O were applied with WDG. CDS contributed 32 lbs N, 31 lbs K20, and 15 lbs S at the 40 lbs P rate. Urea was applied up to the N rate recommended (79 lbs) to prevent deficiency for the check (0 lbs P) and TSP treatments, and less for the 40 lbs P rate of CDS. Sulfur (as ammonium sulfate) was also added to the check plots and those that received TSP. Treatments were surface applied and incorporated. CDS was mixed with water to facilitate manual application to the small plots, 5 x 25 ft.

What Have We Learned?

In 2017, P did not impact yields for both corn and wheat trials. This was probably due to high soil P level, 16 and 13 ppm P from the corn and wheat respective fields, before planting. P sources did not affect yields. Following harvest, P removed with the grain, on a dry weight basis, was significantly greater with WDG (76.2 lbs/ac) compared to TSP (69 lbs). The difference in grain P removed between WDG and CDS (75.7 lbs/ac) was not statistically significant. Neither yields nor protein differed between P sources.

In 2018, yields improved significantly from P application with DGs and TSP as sources. The P unfertilized plot (0 lbs P) produced 42 bushels, which was significantly less (by 10 bushels) than yields at 40 lbs P. Yields were also significantly less at 40 lbs P (by 5 bushels) compared to 80 lbs P. Yields produced by CDS, WDG, and TSP were similar (54 bushels). Earlier in the season, Normalized Difference Vegetation Index data were collected using a remote sensor to provide an index of crop vigor. There were no differences in vigor between P rates. Meanwhile, the crop vigor of TSP treatment was significantly greater than for both DGs. This was likely due to better availability of P and N, early in the growing season, from urea and TSP. However, these nutrients were later available after mineralization from DGs, in amounts that were adequate to satisfy the crop’s needs similar to respective P rates from TSP. Grain P removal was not different between P sources. When averaged across P rates, P removal in the grain was 33 lbs P2O5. Grain P removal was 23, 30, and 35 lbs/ac at 0, 40, and 80 lbs rates, respectively.

effect of P sources on yield of spring wheat at three rates of P plot
Figure 1. Effect of P sources on yield of spring wheat at three rates of P (2017).

Grain protein was significantly greater with WDG compared to CDS and TSP, probably due to higher N applied with DGs at the 80 lbs rate of P, 223 lbs N at 80 lbs P compared to 79 lbs applied with TSP and CDS on a soil that already had 47 lbs and previous crop was soybeans.

Considering the 2018 results and results previously reported from the 2015 and 2016 trials, CDS and WDG can be valuable sources of P and other nutrients for grain crops in North Dakota. For farmers who can transport DGs short distances, pay little or nothing for it, and apply with their manure applicators, they should feel comfortable applying DGs as a good source of P and N.

Future Plans

Some farmers have been curious about the dried distillers grains as P sources. We will conduct another study in 2019 including the dry product (DDG), even though we understand it is very unlikely that farmers would make any profit with the dry product as a source of nutrients.

Authors

Jasper M Teboh, Research Soil Scientist, NDSU – Carrington Research Extension Center

Jasper.Teboh@ndsu.edu

Szilvia Yuja, Research Soil Specialist, NDSU – Carrington Research Extension Center

Additional Information

Where can people go to learn more about this project or research? List journal articles, websites, publications, articles, social media, or other resources.

Please contact me with questions at Jasper.Teboh@ndsu.edu, or by phone at 701-652-2951 (Ext 109).

Results from this research were first presented at the ASA/SSSA/CSSA 2016 annual conference in Phoenix and is accessible at: https://scisoc.confex.com/crops/2016am/webprogram/Paper100533.html

A summary of findings was later presented on the NDSU – Carrington REC blog at: https://www.ag.ndsu.edu/CarringtonREC/center-points/distillers-grains-impacted-yields-of-corn-and-spring-wheat-when-used-as-a-source-of-p

NDSU Carrington Research and Extension Center Annual report, 2018. https://www.ag.ndsu.edu/carringtonrec/documents/annual-reports/2018-annual-report

Acknowledgements

The authors are grateful to the North Dakota Corn Council, and North Dakota Agricultural Products Utilization Commission for funding the corn and wheat projects, respectively, and also to Tharaldson Ethanol (Casselton, ND) for supplying us with the distillers grains.   

 

 

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. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

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Macropore Characterization to Enable the Selection of Practices that Minimize Soluble Phosphorus Loss

Soluble nutrients are believed to be contributing to the recent high-profile impacts in the Great Lakes including excessive cyanobacteria growth (Ohio 2010; Baker et al. 2014).   Retaining nutrients, and especially phosphorus in the Great Lakes region, on crop land is also important to the producer as it is non-renewable, scarce, expensive, exhibits high price variability, and can cause adverse environmental impacts when discharged into fresh water systems.

This research program was designed to quantitatively investigate preferential flow pathways caused by macropores by conducting field analyses using the mobile macropore characterization unit. Such pathways enable soluble nutrients, such as phosphorous, to rapidly migrate through soil, into tile drains, and then to surface water (Geohring et al. 2001; Heathwaite and Dils 2000). Results, along with site characteristics such as farm-management practices, topography, soil texture, depth to water table, depth and spacing of subsurface drains, if applicable, topography, and proximity to surface water, enable the qualitative selection of the best management practice to retain nutrients. This approach recognizes that all farm fields are unique and best practices to maximize nutrient uptake and minimize its transport off site are not equally applicable

What did we do?

Forrer et al., 2000, developed a visual technique to assess liquid flow through microporous soil. The technique entails adding dye to small plots of saturated soil and excavating trenches in each area. This method was expanded by photographing the soil profiles, processing the image to convert pixels with dye to white and soil without dye to black, and quantifying each with depth using MATLAB (Figure 1). The result is an estimate of the amount and extent of the macropores.

Figure 1. Assessment of Soil Macropores
Figure 1. Assessment of Soil Macropores

 

This technique was packaged into the mobile macropore characterization unit to allow for efficient measurements (Figures 2 and 3).

Figure 2. Mobile Macropore Characterization Unit
Figure 2. Mobile Macropore Characterization Unit

 

Figure 3. Dye and Water Distribution Unit using Sprinklers
Figure 3. Dye and Water Distribution Unit using Sprinklers

What we have learned?

Five sites across Michigan with varied management practices and soil structure were tested using the newly developed protocol as shown in Figure 4.  

Figure 4. Representative Images from Five Sites using Dye Tracer Study
Figure 4. Representative Images from Five Sites using Dye Tracer Study

What are the next steps?

The mobile micropore characterization unit will be used extensively at an ongoing edge-of-field monitoring research site in Michigan to develop correlations between soluble pollutants in the tile drain water and quantitative macropore characterization. Thereafter, the unit will be used by extension educators for field-specific measurements to help producers decide on the most appropriate best management practices.     

Authors

Steven I. Safferman1, Jason S. Smith2, Thiramet Sothiyapai3, Ehsan Ghane4

1 Associate Professor; Michigan State University, Biosystems and Agricultural Engineering; Corresponding Author:  SteveS@msu.edu

2 Teaching Specialist, Michigan State University, Engineering CoRe

3 Undergraduate Research Assistant, Michigan State University, Biosystems and Agricultural Engineering

4 Assistant Professor and Extension Specialist, Michigan State University, Biosystems and Agricultural Engineering

Additional Information

Baker, D. B., R. Confesor, D. E. Ewing, L. T. Johnson, J. W. Kramer, and B. J. Merryfield. 2014. “Phosphorus Loading to Lake Erie from the Maumee, Sandusky and Cuyahoga Rivers: The Importance of Bioavailability.” Journal of Great Lakes Research 40 (3): 502–17. https://doi.org/10.1016/j.jglr.2014.05.001.

Forrer, I., A. Papritz, R. Kasteel, H. Flühler, and D. Luca. 2000. “Quantifying Dye Tracers in Soil Profiles by Image Processing.” European Journal of Soil Science 51 (2): 313–22. https://doi.org/10.1046/j.1365-2389.2000.00315.x.

Geohring, Larry D, Oloro V Mchugh, M Todd Walter, Tammo S Steenhuis, M Saleem Akhtar, and Michael F Walter. 2001. “Phosphorus Transport Into Subsurface Drains By Macropores After Manure Applications :” Soil Science 166 (12): 896–909.

Heathwaite, A. L., and R. M. Dils. 2000. “Characterising Phosphorus Loss in Surface and Subsurface Hydrological Pathways.” Science of the Total Environment 251–252: 523–38. https://doi.org/10.1016/S0048-9697(00)00393-4.

Ohio, E P A. 2010. “Ohio Lake Erie Phosphorus Task Force Final Report.” Ohio EPA OH Task Force.

Acknowledgements

This project was funded by the Michigan Soybean Promotion Committee, Corn Marketing Program of Michigan, and Michigan Wheat Program. The author wish to acknowledge contributions from Brendon Kelly, Lyndon Kelly, Steve Miller, and the MSU Soil and Plant Nutrient Laboratory.

 

 

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. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

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Phosphorus Release from Sewage Sludge Incinerator Ash in a Corn and Soybean Field Study

In the Twin Cities, sewage sludge is incinerated and in the process 5 MW of power is generated per day.  Incineration produces significant amounts of ash (38 tons/day) which contains nearly 30% total phosphate (P2O5).  Currently, sewage sludge incinerator ash (SSA) is landfilled at a cost to taxpayers, but previous studies have shown that the ash has the potential to be a source of phosphorus (P) for crop production.  Additionally, P is a limited and difficult-to-renew resource.

What did we do?  

To determine the viability of SSA as a P fertilizer, we are in the middle of conducting a 3-year corn and soybean field study comparing this ash to other P sources including conventional P fertilizer (triple super phosphate), dried pelletized biosolids, and struvite.  Each P source was applied in the spring at 40, 80, 120, and 160 lb P2O5/ha, with a zero-P control included.  Soil and plant samples were taken throughout the season and after harvest and then were analyzed for available P and EPA 503 metals (elements monitored by the EPA in biosolids land application).  In-situ probes that act as a proxy for ions in soil solution were also analyzed.

What we have learned?  

After two years of field studies, there is evidence to show that SSA can be a viable phosphorus fertilizer as well as a source of copper (Cu) and zinc (Zn), although additional years of study on a more P-responsive soil are required to draw definitive conclusions.  While soils amended with biosolids or SSA have higher levels of DTPA-Cu and DTPA-Zn compared with TSP- or struvite-amended soils, only grain concentrations of zinc reflected this difference in source.

While Cu and Zn are both elevated in biosolids and SSA soils, in-situ probes show that these elements are significantly more available in the biosolids-amended soils.  This may be due to the difference in matrices and requires more study. However, our results demonstrate that land-application of ash and biosolids for crop production are two potential options for resolving sewage solids disposal and beneficial reuse of nutrients that go through our food systems.  While land-applying biosolids is a good source of carbon and nitrogen where SSA is not, SSA has the benefit of having minimal organic contaminants (pathogens, pharmaceuticals) due to the incineration process. Additionally, biosolids are applied to meet a crop’s nitrogen requirements whereas SSA is applied to meet a crop’s phosphorus requirements.  Because of this, the total amount of SSA-amendment added is significantly less than biosolids and thus results in lower or equal amounts of EPA 503 metals.

Future plans:

We will continue our study through a third field season (2019) and will continue to monitor P and 503 metals concentrations in soils and uptake by plants.  We are also analyzing soil samples for changes in microbial populations due to SSA application. However, an early proof-of-concept incubation showed no significant effects of SSA when applied at agronomic P-rates.

Authors:

Persephone Ma1, phma@umn.edu

Carl Rosen1

1Department of Soil, Water, and Climate, University of Minnesota, Twin Cities

Additional information:

Bierman P, Rosen C. 1994a. Phosphate and trace-metal availability from SSA. JEQ. 23(4):822-830. Bierman P, Rosen C. 1994b. SSA effects on soil chem-prop and growth of lettuce and corn. Comm in SS and Plant Analysis. 25(13-14):2409-2437. Crants, J., C. Rosen, C. Blake, and M. McNearney. “Is SSAa Safe and Effective Phosphate Fertilizer?” U of Minn, 2015. Abs. Syn in Sci: Partn .for Sol. ASA, CSSA, SSSA, 16 Nov. 2015. Jasinski, S. “Phosphate Rock Statistics and Information.”Phosphate Rock Stat. and Info., USGS, 2017. Walker, J., et al. A Plain English Guide to the EPA Part 503 Biosolids Rule , USEPA, Off. of Ww. Mgmt, 1994.

Acknowledgements:

Metropolitan Council, Rosen Lab field crew, Rosemount Research and Outreach Center field crew, Department of Soil, Water, and Climate field crew

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. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

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Nitrogen and Phosphorus Cycling Efficiency in US Food Supply Chains – A National Mass-Balance Approach


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Purpose 

Assessing and improving the sustainability of livestock production systems is essential to secure future food production. Crop-livestock production systems continue to impact nitrogen (N) and phosphorus (P) cycles with repercussions for human health (e.g. secondary particle formation due to ammonia emission and drinking water contamination by nitrate) and the environment (e.g. eutrophication of lakes and coastal waters and exacerbation of hypoxic zones). Additionally, P is a limited resource, and sustaining an adequate P supply is a major emerging challenge. To develop strategies for a more sustainable use of N and P, it is essential to have a quantitative understanding of the flows and stocks of N and P within the society. In this study, we developed detailed national N and P budgets to assess nutrient cycling efficiency in US (livestock) food supply chains, to identify hotspots of nutrient loss and to indicate opportunities for improvement!

What did we do? 

1. National nutrient mass-balance

A mass-balance framework was developed to quantify nutrient flows within the US. In this framework, the national US system is represented by 9 major sectors are relevant in terms of nutrient flows: mining (relevant for P only), industrial production, agriculture, food & feed processing industry, retail, households and other consumers, energy and transport, humans, and waste treatment. These sectors can exist of several sub-sectors. For example, the agricultural sector consists of several secondary sub-systems including pasture, agricultural soil, livestock and manure management (WMS – waste management system).

Different livestock categories can have distinct environmental impacts and nutrient use efficiencies (e.g. (Hou et al. 2016), (Eshel et al. 2014), (Herrero et al. 2013)), we therefore distinguish six livestock categories (dairy cattle, beef cattle, poultry (meat), poultry (layers), sheep, hogs) and

 their associated food commodities (dairy products, beef from dairy cattle, beef, poultry, eggs, lamb, pork).

For each sub-system, we identify and quantify major flows to and from this compartment. All flows are expressed in a common unit, i.e. metric kiloton N per year (kt N/yr) for nitrogen and metric kiloton P per year (kt P/yr) for phosphorus. Quantified flows include nutrient related emissions to the environment and waste flows.

At present, the waste sectors and environmental compartment are outside the system boundaries, that is, we quantify flows to these compartments, but we do not attempt to balance these sectors. We do, however, keep track of the exact chemical species (e.g. emission of N2O-N to air instead of N to air) emitted as far as possible. The municipal waste treatment (MSW) and municipal waste water treatment (WWTP) are treated in more detail: major flows from and to these compartments are quantified. These sub-sectors are treated in more detail because of their role in nutrient recycling through e.g. sewage sludge application on agricultural soils.

Data were collected in priority from national statistics (e.g. USDA NASS for livestock population) and peer-reviewed literature, and were supplemented with information from industrial reports and extension files if needed. If available, data were collected for the years 2009 to 2012 and averaged, when unavailable, we collected data for the closest year.

2. Scenario analysis

In the scenario analysis, we test the opportunity for dairy livestock production systems to contribute to a more efficient nutrient use through anaerobic co-digestion of dairy manure and organic food waste. Recently, Informa Economics assessed the national

 market potential of anaerobic digester products for the dairy industry (Informa Economics 2013). Next to a reduction in greenhouse gas emissions, anaerobic co-digestion of dairy manure and organic food waste can contribute to improve nutrient cycling efficiency (Informa Economics 2013). Dairy manure contains high levels of nitrogen and phosphorus, which can be used as a natural crop fertilizer, if recuperated from manure. Presently, non-farm organic substrates such as food waste are typically disposed of in landfills, which causes greenhouse gas (GHG) emissions and also results in a permanent removal of valuable nutrients from the food supply chain (Informa Economics 2013). By anaerobic co-digestion, a part of the nutrien! ts contai ned in dairy manure and food waste can be recovered. These nutrients can be used to fertilize crops and substitute synthetic fertilizer application. In the scenario analysis, we test to what extent anaerobic co-digestion of dairy manure and food waste can contribute to improve nutrient cycling efficiency, particularly by substituting synthetic fertilizers. We develop the scenario based on data provided in the InformaEconomics report.

What have we learned? 

In general, our results show that livestock production is the least efficient part of the total food supply chain with large losses associated with manure management and manure and fertilizer application to crops. In absolute terms, the contribution of the household stage to total and N and P losses from the system is small, approximately 5 and 7% for N and P, respectively. However, households ‘waste’ a relatively large percentage of purchased products, (e.g. 16% and 18% of N and P in dairy products end up as food waste), which presents an opportunity for improvement. A scenario was developed to test to what extent anaerobic co-digestion of dairy manure and food waste can contribute to improving nutrient cycling efficiency on a national scale. Results suggest that 22% and 63% of N and P applied as synthetic fertilizer could potentially be avoided in dairy food supply chains by large scale implementation of anaerobic co-digestion o! f manure and food waste.

Future Plans     

Future research plans include a further development of scenarios that are known to reduce nutrient losses at the farm scale and to assess the impact of these scenarios on national nutrient flows and losses.

Corresponding author, title, and affiliation        

Karin Veltman, PhD, University of Michigan, Ann Arbor

Corresponding author email    

veltmank@umich.edu

Other authors    

Carolyn Mattick, Phd, Olivier Jolliet, Prof., Andrew Henderson, PhD.

Additional information                

Additional information can be obtained from the corresponding author: Karin Veltman, veltmank@umich.edu

Acknowledgements       

The authors wish to thank Ying Wang for her scientific support, particularly for her contribution in developing the anaerobic co-digestion scenario.

This work was financially supported by the US Dairy Research Institute.

 

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

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Cultivation of Duckweed on Anaerobically Digested Dairy Manure for Nitrogen and Phosphorus Removal

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Purpose

The purpose of this research included identifying the optimum cultivation conditions of five different strains of duckweed while evaluating the nutrient uptake of nitrogen (N) and phosphorus (P) in anaerobically digested dairy manure to promote biomass production.

What did we do?

The growth of duckweed was assessed on the cultivation parameters of temperature, pH, dissolved oxygen, light intensity, nutrient concentrations, and biomass production. Three strains, namely Landoltia punctata, Lemna gibba and Lemna minuta, were identified as the promising candidates for their high levels of nutrient uptake and biomass production. The temperature and light intensity were maintained in an environmental chamber at 25°C and 10,000 lux, respectively. The nutrient uptake through duckweed cultivation, characterized by the changes of total nitrogen (TN), total Kjeldahl nitrogen (TKN), and total phosphorus (TP), was assessed on the anaerobically digested dairy manure in three dilution ratios i.e., 1:13, 1:18, and 1:27 by volume.

What have we learned?

In the dilution ratios 1:18 and 1:27 all duckweed strains grew successfully. However, in dilution ratio 1:13 all three duckweed species were inhibited by the high nutrient concentration. The batch system created an aerobic environment within the anaerobically digested dairy manure medium with a dissolved oxygen content of 2-6 mg/L. At the high light intensity of 10,000 (lux) a buffer was needed in order to keep the medium’s pH constant to promote duckweed growth. This research compared the nutrient reduction of the microbial growth within the anaerobically digested dairy manure and a standard solution of 1.6 g/L of Hoagland E-medium to the nutrient reduction from the three strains of duckweed at the dilution ratios of 1:13, 1:18, and 1:27. Experimental results revealed that the average duckweed productivities were 1.50, 1.30 and 0.50 grams per square foot per day for Landoltia punctata, Lemna gibba, and Lemna minuta, respectively. At the dilution ratio of 1:27 the highest significant reductions came from Landoltia punctata at 86.0% for TN, 87.5% for TKN, and a TP of 89.5%. At the dilution ratio of 1:18 Lemna gibba got the next highest at 83.8% for TN, 85.6% for TKN, and a TP of 76.2%. Lemna minuta came in last with the highest nutrient reductions in dilution ratio 1:18 with 83.1% for TN, 84.7% for TKN, and a TP of 76.5%. A light intensity of 10,000 lux, pH of 6.5, a temperature of 25°C and a dilution ratio of 1:27 promoted active duckweed growth on anaerobically digested dairy manure.

Future Plans

We will continue the duckweed cultivation work to optimize manure nutrient uptake and to convert duckweed biomass into bioethanol.

Corresponding author, title, and affiliation

Lide Chen, Assistant Professor/Waste Management Engineer, University of Idaho

Corresponding author email

lchen@uidaho.edu

Other authors

Kevin Kruger (University of Idaho)

Additional information

Kevin Kruger is a graduate student who conducted the duckweed cultivation tests.

Acknowledgements

This work is supported by the USDA NIFA and Idaho Agricultural Experiment Station.

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Nutrient Cycling in Horse Pastures


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Purpose 

This presentation will review the existing multi-species literature on nutrient cycling and how it is affected by the horse’s diet and rotational grazing.

Grazed pastures, particularly rotationally grazed pastures, recycle nutrients faster than ungrazed pastures. Nutrients on pasture land enter through animal waste, and waste feed or fertilizer; they leave through removal of forage, leaching/runoff, or animal product/waste removal. Taking away the animal component removes about half of the inputs needed to recycle the nutrients. Dietary nitrogen (N), phosphorus (P) and potassium (K) are required for basic maintenance of horses; however, not all of what is consumed is used by the animal, therefore the dietary concentrations of these nutrients will impact the nutrient cycling. Digestibility of N, P and K in horses is approximately 80, 25 and 75 %, respectively. What does not get digested will end up excreted back into the soil.

What did we do? 

For example, in one study eight Standardbred mares were divided into two groups and received diets of grass hay and grain. The high P (HP) group received 142 g/d of NaH2PO4, formulated to provide 4.5-times the dietary P requirement, or 65 g phosphorus/d. The low P (LP) group received 28 g of phosphorus/d in the basal diet. Data showed that horses receiving the HP diet excreted higher P and water extractable P in the manure than those fed the LP diet (Table 1; Westendorf and Williams, 2015). The same goes for N, where one study used a treatment group that was supplemented with 700 g/d of soybean meal top dressed on 500 g of sweet feed per day (TRT; 1042 g protein/d DM total), while the control group received the sweet feed meals without the soybean meal (CON; 703 g protein/d total). Both groups were also fed 8 kg/d of a grass hay mix (562 g protein /d DM), water and salt ad libitum. Horses fed the TRT diet excreted more N and NH3 than horses fed the CON diet (Figure 1; Williams et al., 2011).

Nutrient Cycling in horse pastures: Tables and Figures

What have we learned? 

More intensive grazing also creates an increased rate of nutrient cycling due to the added animal inputs on the land. Even though no horse related studies have been performed on this topic studies in cattle have found that plant-available N levels doubled when cattle were rotationally grazed with five grazings per season instead of three (Baron et al., 2002). Kenny (2016) looked at horses grazed under either a continuous or rotational grazing system (see Pictures 1 and 2, Left to Right, respectively) and found no differences in system after one year of grazing, however, the author concludes that more time on the system could have generated differences.

Other factors that affect the rate of nutrient cycling include amount of legumes in the pasture, distribution of manure on pastures (i.e. relation to water, shelters and fencing), and use or rates of fertilizer.

 

Horse in pastureRotational grazing horse

Future Plans    

More equine specific studies need to be performed looking at how grazing systems and equine diets affect nutrient cycling and how horse farm owners can utilize this to best manage their farm for optimal nutrient utilization.

Corresponding author, title, and affiliation        

Carey A. Williams, Equine Extension Specialist, Rutgers, the State University of New Jersey, Department of Animal Science

Corresponding author email    

carey.williams@rutgers.edu

Additional information 

References:

Baron, V. S., E. Mapfumo, A. C. Dick, M. A. Naeth, E. K. Okine, and D. S. Chanasyk. 2002. Grazing intensity impacts on pasture carbon and nitrogen flow. J. Range Manage. 55:525-541.

Kenny, L. B. 2016. The Effects of Rotational and Continuous Grazing on Horses, Pasture Condition, and Soil Properties. Master thesis, Rutgers, the State University of New Jersey, New Brunswick, NJ.

Westendorf, M. L., and C. A. Williams. 2015. Effects of excess dietary phosphorus on fecal phosphorus excretion and water extractable phosphorus in horses. J. Equine Vet. Sci. 35:495-498. doi:10.1016/j.jevs.2015.01.020

Williams, C. A., C. Urban, and M. L. Westendorf. 2011. Dietary protein affects nitrogen and ammonia excretion in horses. J. Equine Vet. Sci. 31:305-306.

 

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

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Phosphorus Recovery from Anaerobic Swine Lagoon Sludge Using the Quick Wash Process

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Purpose

Long term and significant accumulation of sludge in anaerobic swine lagoons reduces its storage volume and ability to treat waste. Usually, excess accumulation of lagoon sludge is removed using pump or dredge. The dredged sludge is then land applied at agronomic rates according to its nutrient content.

The accumulation of phosphorus (P) in the sludge requires the largest area of land application based on crop agronomic requirements. Therefore, nutrient management plans may limit application to crop or pastureland near the animal facility to avoid P build up in excess of soil and crop assimilative capacities. Although dewatered sludge can be moved off the farm, transportation becomes less economical with increasing distances. An option is to extract and recover P in a concentrated form for its economical transfer to P-deficient croplands, for use as fertilizer.

What did we do?

A patented treatment process, called Quick Wash (QW), developed by USDA-ARS for extraction and recovery of P from animal manure solids was tested for recovery of P from anaerobic swine lagoon sludge. With the QW process,Chart of Quick Wash Process P was extracted in solution from dredged sludge by mixing with sulfuric acid prior to dewatering using polymer enhanced mechanical solid-liquid separation. After that, P was recovered by addition of liquid lime and an anionic flocculent to the separated liquid extract to form a calcium-containing P precipitate. The QW process generated two solid products: 1) sludge solids low in P; and 2) a concentrated P material.

What have we learned?

Picture of recovered phophorus material from lagoon sludge

While most of the nitrogen and carbon was left in the washed sludge solids, the QW process extracted and recovered as much as 90 % of the P from sludge. From results of a pilot field test, the P grade of the recovered phosphate was in the range of 24.0% – 30.5 % P2O5. The inclusion of this process in a lagoon sludge management plan offers producers an opportunity to locally land-apply the low-P sludge as a carbon-rich soil amendment and recover P as a valuable product for export from the farm.

Future Plans

USDA granted an exclusive license of the invention to Renewable Nutrients, LLC (Pinehurst, NC) to commercialize in the U.S the process for P recovery from animal and municipal waste streams. Renewable Nutrients is developping commercialization plans for the Quick Wash process that will include the operating and equipment costs of phosphorus recovery from dredged lagoon sludge.

Corresponding author, title, and affiliation

Ariel A. Szogi, Research Leader, USDA-ARS Coastal Plains Soil, Water, and Plant Research Center, Florence, SC.

Corresponding author email

ariel.szogi@ars.usda.gov

Other authors

Matias B. Vanotti; and Paul D. Shumaker – USDA-ARS Coastal Plains Soil, Water, and Plant Research Center, Florence, SC.

Additional information

https://www.renewablenutrients.com/

Acknowledgements

This work is part of USDA-ARS National Program 212; ARS Project 6082-12630-001-00D “Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plain.”

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Assessment of Condensed Distillers Solubles (CDS) and Wet Distillers Grains (WDG) as Sources of Phosphorus Fertilizer for Corn and Wheat

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Purpose

Some farmers in North Dakota are showing growing interest in applying coproducts from ethanol production, as sources of nutrients for crop production, especially corn and wheat. The majority of these coproducts are used as livestock feedstuff, but sometimes, due to a combination of factors, ethanol plants have a surplus of condensed distillers solubles (CDS) and wet distillers grain (WDG). Under those circumstances, the price of CDS and WDG can drop significantly, and due to their nutrient content, it might make financial sense to use them as a source of nutrients for crop production instead of commercial fertilizers. Cognizant of current low market prices of wheat and corn, farmers are seeking effective and less expensive sources of nutrients for their crops. Farmers also like the concept of recycling the nutrients exported in the corn kernels back into the soil in the form of CDS and WDG.

What Did We Do?

We conducted studies in Carrington (2015 and 2016) and Fairmount (2015), ND. We assessed the impact of CDS and WDG compared to triple super phosphate (TSP) fertilizer as sources of phosphorus (P), on grain yield and quality of corn (2015 and 2016) at rates of 0, 40, 80, 120 lbs P2O5/ac, and wheat (2016) at rates of 0, 40, 80 lbs P2O5/ac. Treatments were surface applied and incorporated. CDS was mixed with water to facilitate application. The check (0 lbs P) and TSP treatments received recommended N as urea.

Slides of weighing, applying, and mixing WDG

What Have We Learned?

In 2015, corn yields from CDS treatments were consistently greater than yields from WDG and TSP at each P level at Carrington. Corn did not respond to P application at Fairmount. In 2016, corn yields were significantly greater for WDG treatments than for CDS and TSP, which produced similar yields. Wheat yields and protein were also significantly higher for WDG compared to TSP. Therefore, CDS and WDG can be valuable sources of P and other nutrients for grain crops in North Dakota.

Future Plans

We will continue assessing the P fertilizer value of CDS and WDG for corn and wheat in 2017. A separate study will assess in-furrow treatments with CDS. Finally, we will assess soil residual effects from CDS and WDG application to soil on subsequent crops, as well as potential economic implications for farmers.

Authors

Jasper M Teboh, Research Soil Scientist, NDSU – Carrington Research Extension Center

Jasper.Teboh@ndsu.edu

Other Authors

Joel Ransom, Extension Agronomist – Cereal Crops, NDSU – Department of Plant Sciences

Szilvia Yuja, Research Soil Specialist, NDSU – Carrington Research Extension Center

J. Paulo Flores, Precision Ag Specialist, NDSU – Carrington Research Extension Center

Additional Information

Please contact me with questions at Jasper.Teboh@ndsu.edu or by phone at 701-652-2951 (Ext 109).

Results from this research were first presented at the ASA/SSSA/CSSA 2016 annual conference in Phoenix and is accessible at:

https://scisoc.confex.com/crops/2016am/webprogram/Paper100533.html

A summary of findings was later presented on the NDSU – Carrington REC blog at

https://www.ag.ndsu.edu/CarringtonREC/center-points/distillers-grains-impacted-yields-of-corn-and-spring-wheat-when-used-as-a-source-of-p

Acknowledgements

The authors are grateful to the North Dakota Corn Council, and North Dakota Agricultural Products Utilization Commission for funding the corn and wheat projects, respectively. Our gratitude also to Tharaldson Ethanol (Casselton, ND) especially Mr. Keith Finney and Mr. Brad Kjar; Mr. Greg LaPlante, Mr. Chad Deplazes (Research Specialist at NDSU), CREC technicians, staff, and students for field 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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

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