Tag: sidedress

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Optimizing Manure Application Timing for Methane Reduction and Economic Gains through Carbon Credits

Purpose

Methane emissions from manure storages significantly contribute to the livestock industry’s carbon footprint. While various manure management strategies are used to reduce greenhouse gas (GHG) emissions on farms, such as anaerobic digestion and composting, many of these strategies are cost-prohibitive for small-to-medium-sized farms. Strategic manure application timing to limit GHG emissions is a practical, scalable option to reduce methane production in manure storages.

Carbon credits are financial incentives for farmers who adopt practices that reduce greenhouse gas emissions, such as cover crops or methane emissions abatement. These credits can then be sold to companies seeking to offset their emissions. This study evaluates the impact of manure application timing on methane emissions from storages and explores how carbon credits could act as an incentive for farms to employ climate-smart manure management practices. By comparing different manure application strategies (fall, spring, in-season sidedress, and split applications), we assess the methane reductions and improved economics of optimized timing.

What Did We Do?

Methane emissions were estimated using data from a lab-based study conducted by Andersen et al. (2015), who measured methane emissions from deep-pit swine manure at various temperatures. From this data, we created a model incorporating manure production rates and ambient temperature dynamics to predict daily methane emissions from a 4800-head slurry storage and 4800-head deep-pit swine production facility.

Seven application scenarios were compared: fall (November 1), spring (April 15), sidedress (June 1), fall-spring, fall-sidedress, spring-sidedress, and fall-spring-sidedress split applications. Total methane emissions were calculated for each scenario, allowing us to determine the GHG emissions abated by shifting from a fall application to an alternate strategy. An economic assessment was conducted using a $30/metric ton carbon dioxide equivalent (MT CO2e) carbon credit valuation to determine the financial implications of these methane mitigation strategies.

What Have We Learned?

For our swine slurry store model, methane emissions were highest in the single fall application scenario due to the full storage attained during peak summer temperatures, with annual emissions totaling nearly 0.5 MT CO2e/pig-space (Figure 1). Shifting application to spring or sidedress reduced emissions by approximately 50%. Split applications showed a further reduction in emissions by maintaining lower storage volumes throughout the year.

Figure 1: Estimated methane emissions in metric tons of carbon dioxide equivalent (MT CO2e) from slurry storage for fall, spring, sidedress, fall-spring split (F-S), fall-sidedress split (F-SD), spring-sidedress split (S-SD), and fall-spring-sidedress split (F-S-SD) applications.
Figure 1: Estimated methane emissions in metric tons of carbon dioxide equivalent (MT CO2e) from slurry storage for fall, spring, sidedress, fall-spring split (F-S), fall-sidedress split (F-SD), spring-sidedress split (S-SD), and fall-spring-sidedress split (F-S-SD) applications.

From an economic perspective, carbon credits significantly enhanced the financial viability of the new application strategies. Carbon credits from abated emissions are projected to bring a maximum of $10/pig-space, or about $74/acre, to the farm annually in the F-S-SD scenario (Table 1). The improved manure application timing can also benefit crop yield, making a spring or sidedress manure application even more economically favorable.

Table 1: Projected carbon credit income for a 4800-head wean to finish swine farm with a slurry storage for fall, spring, sidedress, fall-spring split (F-S), fall-sidedress split (F-SD), spring-sidedress split (S-SD), and fall-spring-sidedress split (F-S-SD) applications.

Fall Spring Sidedress F-S F-SD S-SD F-S-SD
Carbon Credit Income

($/acre)

 $           –  $    33.63  $    33.71  $    41.95  $    45.82  $    45.69  $    52.06
Carbon Credit Income

($/pig-space)

 $           –  $       6.50  $       6.51  $       8.10  $       8.85  $       8.83  $    10.06

Future Plans

Further research should be conducted to refine the temperature aspect of the model. In the slurry store model, we assume that the manure temperature equals the 10-day average temperature. A study to verify the true manure temperature throughout the year would improve the confidence level of the current model. For deep pit barns, we use measured temperature data from 58 barns over 13 months, but manure temperatures were collected from the manure pump out access port and may not represent average manure temperatures in the barn. Future models to assess differences between deep pit and slurry store emissions will highlight the optimal manure management strategies for limiting GHG emissions.

Using specialized high-clearance irrigation equipment, like the 360 RAIN from 360 Yield Center, could enhance the feasibility of more frequent manure applications, reducing methane emissions while maintaining crop nitrogen availability. Additionally, developing standardized carbon credit protocols for manure management could create opportunities for more producers to monetize methane reduction efforts, further incentivizing climate-smart manure application strategies.

Authors

Presenting author

Jacob R. Willsea, Graduate Research Assistant, Iowa State University Department of Agricultural and Biosystems Engineering

Corresponding author

Daniel S. Andersen, Associate Professor, Iowa State University Department of Agricultural and Biosystems Engineering, dsa@isatate.edu

Additional Information

Andersen, D.S., Van Weelden, M.B., Trabue, S.L., & Pepple, L. M. (2015). Lab-assay for estimating methane emissions from deep-pit swine manure storages. Journal of Environmental Management, 159, 18-26. https://doi.org/10.1016/j.jenvman.2015.05.003

Talkin’ Crap Podcast Episode:

https://talkincrappodcast.buzzsprout.com/2163071/episodes/16472267-timing-is-everything-reducing-methane-emissions-with-manure-management

Andersen Lab Poster Repository:

https://iastate.box.com/s/3kkzdzcjlk9qcfrgbv6mj9x7vdk1v0fp

Acknowledgements

USDA-NRCS

Brent Renner

360 Yield Center

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. 

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Optimizing Manure Nitrogen Application Timing in Corn Production for Sustainability and Profitability

 Purpose

Nitrogen (N) application timing is crucial in balancing crop productivity and environmental sustainability. While fall applications are typical among Iowa corn producers due to favorable field conditions, they pose a high risk of N loss through denitrification, volatilization, and leaching. Spring and in-season sidedress applications offer improved nitrogen use efficiency (NUE) by aligning N availability with crop demand.

This study evaluates the effects of different N application timings—fall, spring, and sidedress—on corn yield and NUE. Using data from 65 site-years, we assess how application timing influences yield, economic returns, and environmental impacts. The findings provide insights into best management practices for improving profitability and sustainability in corn production.

What Did We Do?

A review of studies comparing N application timing in corn production was conducted, including a long-term experiment from the University of Minnesota (1960-1996) and additional datasets totaling 65 site-years. Treatments were separated into three categories: fall, spring, and sidedress. Relative yield was used to normalize data across years, and yield response was modeled using a Mitscherlich-Baule equation (Figure 1).

Figure 1: Yield response curves for 65 site-years of relative yield response data, categorized by season of N application
Figure 1: Yield response curves for 65 site-years of relative yield response data, categorized by season of N application

Economic impacts were analyzed using maximum return to nitrogen (MRTN), which identifies the N rate that maximizes economic return (Figure 2). Corn prices ($4.62/bu) and anhydrous ammonia prices ($0.45/lb N) were used to estimate profitability in each application scenario. The environmental effects were assessed by examining N-loss pathways and the potential for emission reduction of nitrous oxide (N2O), a greenhouse gas estimated to be 273 times more potent than carbon dioxide.

Figure 2: Net income per acre for fall, spring, and sidedress N application. Maximum return to nitrogen (MRTN) is plotted as a circular point on each curve, with the profitable N rate (low and high) within $1/acre bounded by diamond points.
Figure 2: Net income per acre for fall, spring, and sidedress N application. Maximum return to nitrogen (MRTN) is plotted as a circular point on each curve, with the profitable N rate (low and high) within $1/acre bounded by diamond points.

What Have We Learned?

Results show that year-to-year, sidedress applications consistently produce the highest corn yield, followed by spring applications, with fall applications being the least effective. Yield differences are particularly evident in wet years (November to June rainfall > 1 inch above average), where sidedress applications outperform fall by an average of 9% (Figure 3). MRTN analysis shows that sidedress applications require 25% less N than fall applications while achieving higher yields, demonstrating their economic advantage.

Figure 3: Reduction in relative yield between fall and sidedress application in different weather conditions: Dry (greater than 1 inch below average November-to-June precipitation), Average (within ±1 inch of average precipitation), and Wet (greater than 1 inch above average precipitation). Interpreted as the yield loss due to increased exposure of applied N to precipitation.
Figure 3: Reduction in relative yield between fall and sidedress application in different weather conditions: Dry (greater than 1 inch below average November-to-June precipitation), Average (within ±1 inch of average precipitation), and Wet (greater than 1 inch above average precipitation). Interpreted as the yield loss due to increased exposure of applied N to precipitation.

The environmental analysis indicates that reducing N application rates through improved timing could cut N2O emissions by up to 25%. With a carbon credit of $30/metric ton CO2e abated the reduction in N2O equates to a $2.66/acre credit for a reduced N application rate. Fall-applied N is most susceptible to losses due to prolonged exposure to wet conditions, while spring and sidedress applications minimize the risk of loss by reducing time in the field and matching crop demand.

Future Plans

Further research is needed to refine N application strategies by incorporating real-time weather data and precision agriculture tools. The development of high-clearance application equipment, such as 360 RAIN from 360 Yield Center, offers opportunities for more flexible and targeted in-season applications, potentially enhancing NUE and reducing losses.

Additional studies should assess the risk of spring or sidedress applications from year to year. Weather conditions often limit pre-plant N application, so a thorough analysis of the frequency and financial impact of interrupted field management operations should be conducted.

Future studies should also explore the economic feasibility of split applications, which combine the benefits of multiple timings to reduce risk. Additionally, expanding MRTN models to include seasonal effects would improve decision-making for producers seeking to optimize N application timing while minimizing environmental impact.

Authors

Presenting author

Jacob R. Willsea, Graduate Research Assistant, Iowa State University Department of Agricultural and Biosystems Engineering

Corresponding author

Daniel S. Andersen, Associate Professor, Iowa State University Department of Agricultural and Biosystems Engineering, dsa@iastate.edu

Additional Information

Talkin’ Crap Podcast Episode:

https://talkincrappodcast.buzzsprout.com/2163071/episodes/15629592-the-power-of-manure-timing-enhancing-nitrogen-efficiency

Andersen Lab Poster Repository:

https://iastate.box.com/s/4s9gjhkd93d95yvqip8q5rr46frshtln

https://iastate.box.com/s/icg6clbamksfzciw8ze3lc301p8homg1

Acknowledgements

USDA-NRCS

Brent Renner

360 Yield Center

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.  

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Sidedressing Corn: Swine Manure via Dragline Hose Produces Yields Comparable to Synthetic Fertilizer

Spring in the upper Midwest can be short, resulting in challenges for producers to apply manure and plant crops in a timely manner to maximize yield. This results in a significant       amount of manure applied in the fall after the crop is harvested. Fall applied manure has ample time to mineralize and leave the root zone before next season’s crop can utilize the nutrients. These nutrients can end up in rivers and other freshwater bodies decreasing water quality. Sidedressing manure in growing crops could provide producers with another window of opportunity to apply their manure, maximize nutrient uptake efficiency, and protect water quality. The summer of 2018 was the start of a two-year, on-farm study researching the effectiveness of sidedressing slurry swine manure to corn via dragline hose. The swine manure was compared to sidedressed anhydrous ammonia, 32% urea ammonium nitrate (UAN), and a  control that received no additional nitrogen at the time of sidedressing.

What we did

Corn was planted May 7th with a 12-row planter equipped to apply an in-furrow and top dressed liquid fertilizer. The total fertilizer applied at planting was 40.7 lbs of nitrogen (N), 19.8 lbs of P2O5 phosphorus (P), and 14.4 lbs of sulfur (S) per acre.

Sidedressing the nitrogen sources

We sidedressed all treatments on June 4-5 with 140 pounds of available N, except the control which had no additional N applied. All the equipment applied nutrients between 30-inch rows and fit a 12-row planter to match up on odd rows.

  • Anhydrous ammonia treatment = 12-row toolbar and tractor were supplied by the farmer.
  • Finishing hog manure dragline hose treatment = The toolbar for the dragline hose sidedress was supplied by Bazooka Farmstar. The toolbar is a coulter till 28-foot bar with 30-inch spacing.
  • UAN treatment = The tool bar for the UAN sidedress application was provided by a local farmer.
  • Control treatment = The control treatment did not receive any fertilizer at sidedress.
Swine manure slurry being applied via dragline hose and Bazooka Farmstar sidedress bar.
Swine manure slurry being applied via dragline hose and Bazooka Farmstar sidedress bar.

Soil data collection methods

Soil nitrate and ammonium samples were taken 5 times through the growing season, approximately every 4 weeks, to track nitrogen in the soil profile. Soil sample depths were 0-6, 6-12, and 12-24 inches from the soil surface. Soil

Two foot soil sampling with tractor probe.
Two foot soil sampling with tractor probe.

samples were taken from the middle of the interrow, 7.5 inches from both sides of the middle of the inter row and in the middle of the row. This sample method assured soil samples would be representative of the soil profile since banded fertilizer can skew results.

Yield data collection methods

Yield was harvested October 6th by a combine with a 6-row head. The combine took the middle 12 rows of the 24-row treatment reducing the side effects from neighboring treatments. A calibrated weigh wagon measured the weight of each combine pass which was calculated to find yield in bushels per acre for every sample.

What we have learned

First year data revealed all sidedressed nitrogen sources significantly increased corn yields over the control but were otherwise statistically similar (Figure 1).

Figure 1. Yield data from 2018 manure sidedress trial in bushels per acre. AA=anhydrous ammonia, UAN=urea ammonium nitrate, Control=received no additional N at sidedress, and Dragline=swine manure slurry applied via dragline hose.
Figure 1. Yield data from 2018 manure sidedress trial in bushels per acre. AA=anhydrous ammonia, UAN=urea ammonium nitrate, Control=received no additional N at sidedress, and Dragline=swine manure slurry applied via dragline hose.

When we analyzed the soil inorganic nitrogen by each date differently, nitrogen concentrations between treatments were only statistically different on the soil sample date of June 15th (Figure 2) This soil sample date was ten days after the sidedress application on June 4th.  All other soil nitrogen sample dates are not statistically different between treatments and even the control.  

Figure 2. Total soil inorganic N (ammonium and nitrate) by treatment and sample date.
Figure 2. Total soil inorganic N (ammonium and nitrate) by treatment and sample date.

Statistics have not yet been run on the whole plant nitrogen content data in the graph below but numerically there doesn’t seem to be a difference in nitrogen content between the three sidedress treatments but a difference from the control (Figure 3).

Figure 3. Percent nitrogen in harvest grain, R6 cobbs, and R6 stover between treatments.
Figure 3. Percent nitrogen in harvest grain, R6 cobbs, and R6 stover between treatments.

Future plans

The first year of data was collected during the 2018 growing season and a second year of data will be collected in the summer of 2019. This study aims to evaluate the effectiveness of sidedressed swine manure slurry compared to traditionally used synthetic fertilizers. Since we have seen promising results this first year an additional study that could follow this experiment would be a direct comparison of fall applied swine manure and sidedressed swine manure. This information would help us understand the efficiency of sidedressing compared to fall application. Soil samples from this study would also illustrate the difference in mineralization and nitrogen movement between fall-applied and sidedressed swine manure slurry.    

Authors

  • Chris Pfarr, M.S. student in the Land and Atmospheric Sciences Program, University of Minnesota, pfarr025@umn.edu
  • Melissa Wilson, Ph.D., Assistant Professor and Extension Specialist, Department of Soil, Water, and Climate, University of Minnesota, mlw@umn.edu

Additional information

Acknowledgements  

This project was partially funded by the Minnesota Soybean Research and Promotion Council and the Minnesota Pork Board.

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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