This webinar highlights literature reviews and studies to reveal what is known now and how the results are currently and will continue shape future research on soil health and manure’s effect on it. This presentation originally broadcast on February 17, 2023. Continue reading “Manure and Soil Health: Current Research and Future Directions”
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?
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:
|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|
|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|
|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|
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.
Corresponding Author: Linda Schott, Assistant Professor/ Extension Specialist- Nutrient and Waste Management, University of Idaho, email@example.com
Other Authors: Amy Schmidt, Associate Professor/ Livestock Bioenvironmental Engineer, University of Nebraska-Lincoln; Humberto Blanco-Canqui, Associate Professor, University of Nebraska-Lincoln
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/
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.
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.
February 9, 2017
|Manure and Soil Health Testing||Bianca Moebius-Clune
February 16, 2017
|Manure and Soil Biology||Rhae Drijber
Dr. Jonathan Lundgren
February 23, 2017
|Manure and Soil Erosion, Runoff, and Losses||Nathan Nelson
March 9, 2017
|Manure and Cover Crops||Tim Harrigan
This webinar looks at current practical research in South Dakota and Michigan related to manure use as it relates to soil health. This presentation was originally broadcast on March 1, 2019. More… Continue reading “Using Manure to Improve Soil Health”
This webinar focuses on the relationships of land applied livestock manure and other organic materials to soil aggregation, resistance to erosion and microbial dynamics in consideration of field characteristics. This presentation was originally broadcast on May 18, 2018. More… Continue reading “Animal Manure’s Impact on Soil Properties”
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.
Tim Harrigan, Michigan State University
Barry Fisher, NRCS Regional Soil Health Coordinator
Heidi Johnson, University of Wisconsin
Sarah Carlson, Practical Farmers of Iowa
Other Manure and Soil Health (MaSH) Information
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.
Nathan Nelson, Kansas State University
John Gilley, USDA Agricultural Research Service
Mike Kucera, NRCS National Soil Survey Center
Andy Scholting, Nutrient Advisors
Other Manure and Soil Health (MaSH) Information
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.
Bianca Moebius-Clune, NRCS Soil Health Division
Russ Dresbach and Donna Brandt, Missouri Soil Health Assessment Center
Geoff Ruth, Nebraska Crop Farmer
Other Manure and Soil Health (MaSH) Information
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.