Impact of Animal Manure and Organic Biosolids on Properties Contributing to Soil Health

The high concentration of organic carbon (C) and plant essential nutrients in manure and organic biosolids make them excellent fertilizers. However, manure is greatly underutilized as a fertilizer; only about 22% of the manure produced worldwide is applied as fertilizer (FAO 2018). This underutilization can yield regional nutrient imbalances when inorganic fertilizers are imported to meet crop nutrient needs that locally produced fertilizers could supply. However, with this challenge comes opportunity as the campaign to improve agricultural soil health has gained momentum among conservationists and researchers worldwide. Thus, a comprehensive assemblage of outcomes from manure and soil health-related research studies is important. Particularly, the identification of knowledge gaps is an important step to direct future research that informs soil health improvement outreach programs.

What did we do?

 Soil health properties included in systematic literature review related to livestock manure and organic biosolids.
Figure 1. Soil health properties included in systematic literature review related to livestock manure and organic biosolids.

We conducted a systematic literature review based on peer-reviewed studies that evaluated the effect of livestock manure and organic biosolids on soil health properties. Soil health properties included in the review are shown in Figure 1. All studies included had to be replicated field trials written in English where manure or organic biosolid application was the only differing factor between treatments. Additionally, included data had to be statistically analyzed to compare organically amended treatments to a control. A total of 163 studies met all criteria.

What have we learned?

Overall, manure and biosolid applications have the potential to improve the health of agricultural soils. These organic amendments add significant amounts of organic C to soil, which has positive effects on other soil health metrics. When compared to inorganic fertilizers, soils that have had application of livestock manure or organic biosolids have the following properties:

Physical
decreased bulk density
more resistant to compaction, especially when wet
increased water holding capacity (WHC) in fine-textured soils with no effect in course textured soils
varied effect on aggregate stability
increased saturated hydraulic conductivity and infiltration
Biological
increased microbial biomass C and microbial biomass N
increased bacterial and fungal populations but no effect on diversity as measured by PLFA
increased microbial respiration and potential N mineralization
no change in microarthropod population and diversity
increased earthwork population
Chemical
increased soil organic C and soil organic matter, in general
varied effect on soil NPK; depends on study methodology (application rate and timing, amendment type, etc.)
varied effect on pH; depends on initial soil pH, amendment pH, and application rate
increased cation exchange capacity due to increased soil organic C

Future Steps

The evaluation of the impact of manure and biosolids on soil health properties is difficult to do based on current literature because 1) there are inconsistent research methodologies between individual research studies, and 2) there are few comprehensive studies that have included all soil health properties. Improvements in research methodologies needs to be improved to fill substantial knowledge gaps identified with this review. Specifically, future research should: (1) quantify soil biological metrics, (2) investigate the short- and long-term effects of a single application of manure or biosolids, (3) study nutrient application balance on an annual or multi-year basis, and (4) discuss how research findings translate into management decisions relevant to agricultural crop producers.

Authors

Corresponding Author: Linda Schott, Assistant Professor/ Extension Specialist- Nutrient and Waste Management, University of Idaho, lschott@uidaho.edu

Other Authors: Amy Schmidt, Associate Professor/ Livestock Bioenvironmental Engineer, University of Nebraska-Lincoln; Humberto Blanco-Canqui, Associate Professor, University of Nebraska-Lincoln

Additional Information

FAO. (2018). Nitrogen inputs to agricultural soils from livestock manure. New statistics. Integrated Crop Management (Vol. 24). Rome, Italy

More information on this project can be found at: https://soilhealthnexus.org/resources/manure-and-soil-health/

Acknowledgements

This project was supported by funding from the North Central Region Water Network and the Soil Health Institute. The authors would also like to thank Mara Zelt and Ashley Schmit for their assistance.

 

 

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.

Manure & Soil Health: Roundtables to Advance our Understanding of the State of the Science

Farmers and ranchers are becoming increasingly aware of the importance of soil quality/health to the productivity and sustainability of their agricultural system. Research and field observations have demonstrated that carefully managed manure applications can contribute to improved soil quality with limited environmental and social risks. However, a comprehensive assemblage of outputs and conclusions from research studies, field trials, soil labs databases, and other sources has never been developed. Therefore, the purpose of the initiative, Manure & Soil Health: Understanding and Advancing the State of the Science, is to assemble current knowledge on this topic, make it available to those influencing manure and land management decisions, and use it to inform and facilitate future research and service needs. The intent of the roundtables is to improve our understanding of: current knowledge, critical and emerging issues for which there are knowledge gaps, and information needs of farmers and their advisors.

What’s A Roundtable?

The four, hour-long roundtables consisted of a panel discussion with experts who were asked to summarize their current understanding of topics. Each panel also included a practitioner who shared perspectives on critical information needs of farmers and advisors and field experiences relative to use of manure. Panels were moderated to encourage interaction with audience. Roundtable participants were invited to ask questions of panelists and share expertise and experience.

When Were The Roundtables Held?

Date/Time Topic Panel Experts

February 9, 2017

Manure and Soil Health Testing Bianca Moebius-Clune
Donna Brandt
Russell Dresbach
Geoff Ruth

February 16, 2017

Manure and Soil Biology Rhae Drijber
Michele Soupir
Dr. Jonathan Lundgren

February 23, 2017

Manure and Soil Erosion, Runoff, and Losses Nathan Nelson
John Gilley
Mike Kucera
Andy Scholting

March 9, 2017

Manure and Cover Crops Tim Harrigan
Barry Fisher
Heidi Johnson
Sarah Carlson

Manure and Cover Crops

In the Manure and Cover Crops roundtable, our goal was to discover whether manure and cover crops have complementary benefits related to soil quality. We debated if certain fields will produce more complementary benefits than others and whether timing of application and sampling affects these benefits. Finally, we’ll discussed whether we can derive an economic value for manure beyond its nutrient value. Field experiences and observations related to the value of manure as well as what farmers still need related to soil building with manure were discussed. This dialogue was the final of a four part series discussing the current state of our knowledge relative to manure’s impact on soil health.

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Tim Harrigan, Michigan State University

Barry Fisher, NRCS Regional Soil Health Coordinator

Heidi Johnson, University of Wisconsin

Sarah Carlson, Practical Farmers of Iowa

Discussion

Other Manure and Soil Health (MaSH) Information

Manure and Soil Erosion, Runoff, and Losses

In the Manure and Soil Erosion, Runoff, and Losses roundtable, our goal was to discover the influence of manure on soil and runoff. We discussed if certain fields will produce more environmental benefits than others and whether timing of application affects these benefits. Finally, we debated whether we can derive an economic and environmental value for manure beyond its nutrient value, due to improved moisture retention and decreased erosion. Field experiences and observations related to the value of manure as well as what farmers still need related to soil building with manure were reviewed. This dialogue was the third in a four part series discussing the current state of our knowledge relative to manure’s impact on soil health.

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Nathan Nelson, Kansas State University

Presentation Slides

John Gilley, USDA Agricultural Research Service

Presentation Slides

Mike Kucera, NRCS National Soil Survey Center

Presentation Slides

Andy Scholting, Nutrient Advisors

Presentation Slides

Discussion

Other Manure and Soil Health (MaSH) Information

Manure and Soil Health Testing

In the Manure and Soil Health Testing roundtable, our goal was to discover what current soil health tests help to quantify manure impacts on soil characteristics, thus determining which soil test is the best indicator and best value. We debated which types of fields might benefit most from manure used to improve soil health and procedures for collecting samples for soil health tests that would best recognize results from use of manure. Field experiences and observations related to the value of manure as well as what farmers still need related to soil building with manure were discussed. This dialogue was the first of a four part series discussing the current state of our knowledge relative to manure’s impact on soil health.

If you have difficulties please see our webcast troubleshooting page. If you need to download a copy of a segment, submit a request.

Bianca Moebius-Clune, NRCS Soil Health Division

Russ Dresbach and Donna Brandt, Missouri Soil Health Assessment Center

Geoff Ruth, Nebraska Crop Farmer

Discussion

Other Manure and Soil Health (MaSH) Information

Manure and Soil Biology

In the Manure and Soil Biology roundtable, our goal was to discover the influence of manure, both positive and negative, on soil biology. We discussed if certain fields will produce more soil biology benefits than others and whether timing of application affects these benefits. Finally, we debated whether we can derive an economic value for manure beyond its nutrient value. Field experiences and observations related to the value of manure as well as what farmers still need related to soil building with manure were reviewed. This dialogue was the second in a four part series discussing the current state of our knowledge relative to manure’s impact on soil health.

If you have difficulties please see our webcast troubleshooting page. If you need to download a copy of a segment, submit a request.

Rhae Drijber, University of Nebraska – Lincoln

Michelle Soupir, Iowa State University

Jonathan Lundgren, Blue Dasher Farms

Discussion

Other Manure and Soil Health (MaSH) Information