Microarthropods as Bioindicators of Soil Health Following Land Application of Swine Slurry


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*Purpose 

As producers of livestock and agricultural crops continue to focus significant efforts on improving the environmental, economic, and social sustainability of their systems, increasing the utilization of livestock manure in cropping systems to offset inorganic fertilizer use benefits both sectors of agriculture. However, promoting manure based purely upon nutrient availability may not be sufficient to encourage use of organic versus inorganic fertilizer. The value of livestock manure could increase significantly with evidence of improved soil fertility and quality following manure application. Therefore, understanding the impact of manure addition and application method on both soil quality and biological health is an important step towards improving the value and desirability of manure for agricultural cropping systems.

For edaphic ecosystems, collection, analysis, and categorization of soil microarthropods has proven to be an inexpensive and easily quantified method of gathering information about the biological response to anthropogenic changes to the environment (Pankhurst et al., 1995; Parisi et al., 2005). Arthropods include insects, crustaceans, arachnids, and myriapods; nearly all soils are inhabited by a vast number of arthropod species. Agricultural soils may contain between 1,000 and 100,000 arthropods per square meter (Wallwork, 1976; Crossley et al., 1992; Ingham, 1999). Soil microarthropods show a strong degree of sensitivity to land management practices (Sapkota et al., 2012) and specific taxa are positively correlated with soil health (Parisi et al., 2005). These characteristics make soil microarthropods exceptional biological indicators of soil health.

This study focused on assessing the chemical and biological components of soil health, described in terms of soil arthropod population abundance and diversity, as impacted by swine slurry application method and time following slurry application.

What did we do? 

A field study was conducted near Lincoln, Nebraska from June 2014 through June 2015 on a site that has been operated under a no-till management system with no manure application since 1966. Experimental treatments included two manure application methods (broadcast and injected) and a control (no manure applied).

Soil samples were collected twelve days prior to treatment applications, one and three weeks post-application of manure, and every four weeks, thereafter, throughout the study period. Samples were not collected during winter months when soil was frozen.

Two types of soil samples were collected. Samples obtained with a 3.8-cm diameter soil probe were divided into 0-10 and 10-20 cm sections for each of the plots for nutrient analysis at a commercial laboratory. Samples measuring 20 cm in diameter and 20 cm in depth, yielding a soil volume of 6,280 cm3, were stored in plastic buckets with air holes in the lids, placed in coolers with ice packs, and transported to the University of Nebraska-Lincoln West Central Research & Extension Center in North Platte, Nebraska within 12 h of collection. These samples were then transferred to Berlese-Tullgren funnels for extraction of arthropods, a commonly used technique to assess microarthropods in the soil (Ducarme et al., 2002). A 70% ethanol solution was used to preserve the organisms for later analysis.

The QBS method of classification was employed to assign an eco-morphological index (EMI) score on the basis of soil adaptability level of each arthropod order or family (Parisi et al., 2005). Preserved arthropods from each soil sample were identified and quantified using a Leica EZ4 stereo microscope (Leica Biosystems, Inc., Buffalo Grove, IL) and a dichotomous key (Triplehorn and Johnson, 2004). Arthropods were classified to order or family based on the level of taxonomic resolution necessary to assign an EMI value as described by Parisi et al. (2005). For some groups, such as Coleoptera, characteristics of edaphic adaptation were used to assign individual EMI scores.

The impacts of swine slurry application method and time following manure application on soil arthropod populations and soil chemical characteristics was determined by performing tests of hypotheses for mixed model analysis of variance using the general linear model (GLM) procedure (SAS, 2015). The samples were tested for significant differences resulting from time and treatment, as well as for variations within the treatment samples. Following identification of any significant differences, the least significant differences (LSD) test was employed to identify specific differences among treatments. P <0.05 was considered statistically significant.

What have we learned? 

A total of 13,311 arthropods representing 19 orders were identified, with Acari (38.7% of total arthropods), Collembola: Isotomidae (26.8%), Collembola: Hypogastruridae (10.4%), Coleoptera larvae (1.6%), Diplura (1.2%), Diptera larvae (0.9%), and Pseudoscorpiones (0.6%) being the most abundant soil-dwelling taxa. These taxa had the greatest relative abundance in samples throughout the study and were, therefore, chosen for statistical analysis of their response to manure application method and time since application.

The most significant responses to application method were found for collembolan populations, specifically for Hypogastruridae and Isotomidae. However, Pseudoscorpiones were also significantly affected by application method. Time following slurry application had a significant impact on most of the analyzed populations including Hypogastruridae, Isotomidae, mites, coleopteran larvae, diplurans, and dipteran larvae. The positive response of Hypogastruridae and Isotomidae collembolans to broadcast swine slurry application was likely due to the addition of nutrients (in the form of OM and nitrates) to the soil provided by this form of agricultural fertilizer.

Future Plans   

Research focused on the role of livestock manure in cropping systems for improved soil quality and fertility is underway with additional soil characteristics being monitored under multiple land treatment practices with and without manure.

Corresponding author, title, and affiliation       

Dr. Amy Millmier Schmidt, Assistant Professor, University of Nebraska – Lincoln

Corresponding author email 

aschmidt@unl.edu

Other authors   

Nicole R. Schuster, Julie A. Peterson, John E. Gilley and Linda R. Schott

Additional information               

Dr. Amy Millmier Schmidt can also be reached at (402) 472-0877.

Dr. Julie Peterson, Assistant Professor of Entomology, University of Nebraska – Lincoln can be reached at (308) 696-6704 or Julie.Peterson@unl.edu.

Acknowledgements      

Eric Davis, Ethan Doyle, Mitchell Goedeken, Stuart Hoff, Kevan Reardon, and Lucas Snethen are gratefully acknowledged for their assistance with field data collection. Kayla Mollet, Ethan Doyle, and Ashley Schmit are acknowledged for their assistance with data processing. This research was funded, in part, by faculty research funds provided by the Agricultural Research Division within the University of Nebraska-Lincoln Institute of Agriculture and Natural Resources.

 

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.

Utilization of Woody Biomass and Manure as Agricultural Soil Amendments in Nebraska


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Purpose 

While Eastern Redcedar are native to Nebraska and much of the Central U.S., the ability of these trees to thrive in many soils and under a broad range of climatic conditions has contributed to their designation as an invasive species. Cedar tree proliferation negatively impacts agriculture by reducing groundwater availability, compromising grazing land, impeding forage production for cattle, and altering surface water flows. Agricultural crop and livestock producers depend on affordable access to water, healthy and productive soils, and quality grazing land to remain profitable. Land treatment practices that return organic matter to soil improve soil health, which in turn positively impacts crop productivity, soil water holding capacity, soil fertility, and grazing land forage quality and productivity. This project is investigating the use of two readily available by-products in Nebraska, livestock manure and cedar tree wood chips,  as amendments on agricultural land to improve soil productivity metrics. The overall goal of this project is to demonstrate a value-added use for woody biomass to offset the cost of tree management activities and encourage landowner management of cedars.

What did we do? 

Crop year 2016 was the first year of the Woody Biomass and Manure Project. Six treatments were applied to 12-m x 10-m plots within cooperators’ fields following the 2015 harvest:

1. woody biomass (WB1), 6 ton/ac

2. woody biomass (WB2), 12 ton/ac

3. woody biomass with liquid N (WBLN), 6 ton/ac

4. woody biomass with swine manure (WBSM), 6 ton/ac

5. woody biomass with cattle manure (WBCM), 6 ton/ac

6. control (Cont), no amendments

Manure and liquid nitrogen treatments received less than 30 lbs ac-1 of N in the fall. The experiment is a completely randomized block design with four replications of each treatment, for a total of 24 plots, at each of the sites. Since the plots were established within existing crop fields, the producers were encouraged to continue their current management strategies. Both sites were irrigated, and fertilizer was applied uniformly across all plots using the pivot throughout the growing season.

Soil was sampled for chemical and biological properties in the spring and fall of 2016 and sent to a commercial lab for analyses. Rye was sampled by hand harvesting 0.25 square feet from four locations within each plot for a total of 1 square foot. Corn was sampled by hand harvesting six plants from each plot. Stand counts were also completed. WATERMARK sensors were installed at three depths (1, 2, and 3 ft) in two replications of four treatments (WBCM, WB1, WB2, Cont) at both sites. Additionally, temperature sensors were installed at a depth of 1 ft. A total of 16 plots were monitored (8 plots per site with 2 replications of 4 treatments).

What have we learned? 

Soil biological and chemical characteristics have not been affected during the first year. There were no differences in the amount or type of soil microbes due to treatment. WBCM and WBLN had greater soil nitrate than WB1 and WBSM early in the spring. Additionally, WBCM had greater soil K than the other treatments. Other than these two instances, there were no differences in organic matter, pH, and macronutrients. However, this is not surprising since measurable changes in soil properties typically occur over many years and manure application rate was relatively low. More importantly, though, is that microbial populations were not decreased by the cedar mulch.

Cedar mulch applications did not decrease biomass yield of corn and rye when applied with nitrogen. In fact, in the rye, WBLN had the greatest biomass yields followed by WBCM, WB1, WBSM, and Cont. WB2 had the lowest rye biomass, which was probably due to nitrogen tie-up by the wood chips due to the initially higher C:N ratio. There was no treatment effect for corn biomass or stand counts.

At the site planted to corn at a depth of one foot, the three woody biomass treatments monitored (WB1, WB2, and WBCM) were significantly wetter and cooler than the control from mid-June until mid-July. WBCM was also wetter at a depth of two feet than the control. Unfortunately, due to rodent activity, statistical analyses at the rye site and other times of the growing season are not possible. The differences in soil moisture and temperature are probably due to shading and the physical barrier to evaporation that the wood chips supply. The increased soil moisture under the woody biomass treatments could reduce irrigation.

Future Plans  

In order to apply for competitive funding, we need more supporting data. We are going to increase monitoring of soil moisture and temperature, so that three replications of all six treatments are monitored at both sites. Additionally, a greenhouse study will be conducted to provide water quality data and rate of decomposition of the wood chips.

Corresponding author, title, and affiliation       

Linda Schott, Extension Graduate Research Assistant, University of Nebraska-Lincoln

Corresponding author email   

linda.rae.schott@gmail.com

Other authors   

Amy Schmidt, Assistant Professor, University of Nebraska-Lincoln; Amy Timmerman, Associate Extension Educator, University of Nebraska-Lincoln; Adam Smith, Assistant Forester, Nebraska Forest Service

Additional information               

More information can be found at: manure.unl.edu

Acknowledgements       

This project is funded by the Nebraska Forest Service. We would like to thank the Middle Niobrara Natural Resource District, especially Mike Murphy, Travis Connot, and Zach Peterson, for their assistance to this project. We would also like to thank the Nebraska Forest Service, especially Richard Woollen, Adam Smith, and Heather Nobert, for their assistance to this project. Additionally, this project would not be possible without our two farmer cooperators, Leonard Danielski and Greg Wilke.

USDA-NRCS Conservation Practice Standard: Amending Soil Properties with Gypsum Products


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The US Department of Agriculture National Resource Conservation Service is tasked with providing support to preserve the nation’s natural resources.  They provide farmers with financial and technical assistance to voluntarily put conservation practices on the ground by promoting methods to preserve and improve natural resources and promoting Best Management Practices for environmentally sound farm production.  The NRCS uses technical guides or “Conservation Practice Standards”, which contain technical information about the conservation of soil, water, air, and related plant and animal resources, as the primary scientific references for this process.  Recently, the NRCS has developed a new national conservation practice standard for the use of gypsum to improve soil resources.  This presentation will discuss the specifics of this standard and the particular relevance to animal waste management.

The NRCS national conservation practice standards entitled “Amending Soil Properties with Gypsum Products” has the following definition: using gypsum- (calcium sulfate dihydrate) derived products to change the physical and/or chemical properties of soil.  The standard outlines the use of gypsum for four different purposes, two of which are directly related to animal waste management.  These two purposes are: 1) Improve surface water quality by reducing dissolved phosphorus concentrations in surface runoff and subsurface drainage, and 2) Improve water quality by reducing the potential for pathogens and other contaminants from moving from areas of manure and biosolids application.  The specific guidance provided in the standard for these two purposes will be discussed.  There are also concerns regarding gypsum use in agriculture which are addressed in the standard.  The guidance regarding these concerns will also be discussed.  Within NRCS, the promotion of Best Management Practices for the natural resource conservation is handled on a state by state bases.  This allows each state to focus on the issues that are most important for their specific region.  An update of the current activities of the NRCS for financial and technical assistance in regards to gypsum use will be discussed.    

Author

H. Allen Torbert

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.

 

Resources on Manure and Soil Health

Manure has long been used as a crop fertilizer and soil amendment. Research has shown that manure application can positively impact infiltration rates, soil aggregation, water holding capacity, and crop yields.

While manure can be beneficial, overapplication is not. Too much manure in one place can lead to problems with salt buildup and excess nutrients which can lead to problems with water quality. As with most other inputs, manure is most valuable when it is managed to be in balance with plant needs.

What Is Soil Health?

The United Nations Food and Agriculture Organization (FAO) and the USDA Natural Resource Conservation Service both use the following as the definition of soil health developed by Pankhurst et al., 1997.

The continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans.

Resources On Land Application of Manure and Impacts on Soil Health

[Roundtable Series] Four roundtable webinars will focus on soil health testing, soil biology, soil erosion, and cover crops as they pertain to manure application. The weekly series runs from February 9-March 9, 2017. More…

[Article] Environmental Benefits of Manure Application

[Recorded webinars]

Each of the resources listed above includes links to research articles, extension publications, and more. The MaSH webinar also includes information in how to become involved in the learning network and to read or contribute to the project blog.

[Learning Network] The Soil Health Nexus is sponsored by the North Central Water Network but welcomes interested people from all regions

[Book] Sustainable Agriculture Research and Education (SARE) program “Building Soils for Better Crops 3rd Edition“. The sections most relevant to manure and soil health are linked below.

Animal Manures for Increasing Organic Matter and Supplying Nutrients

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

Swine Manure Application Method Impact on Soil Arthropods


Does Manure Application Impact Soil Arthropods? *

Soil arthropod populations and diversity provide an indication of the biological quality of soil, which can impact soil fertility. Arthropods include insects, crustaceans, arachnids, myriapods, and scorpions and nearly every soil is inhabited by many different arthropod species. Row-crop soils may contain several dozen species. One particular arthropod species, mites, can have a significant impact on nutrient release in soil. For this study, the impact of swine manure slurry applied via broadcast and injection at a rate designed to meet the agronomic nitrogen needs of corn was investigated to determine the manure application method impact on soil arthropod population and diversity.

What did we do?

Treatments include broadcasted swine slurry, injected swine slurry, and non-manured check plots with four replications per treatment. Plots have been monitored following manure application in June 2014 and will continue through June 2015. Soil samples were removed 4 d prior to manure application and at 1, 2, and 4 weeks and monthly thereafter from 0 to 8 inches on each plot. Arthropods were extracted by use of Burlese funnels and collected species are being sorted and characterized.

What have we learned?

Species characterization is on-going and will be summarized for presentation in the poster session at the conference.

Future Plans

Results of this work will allow us to better understand the impact of manure application on soil biological properties, a component in defining the overall fertility or “health” of soil.

Authors

Amy Millmier Schmidt, Assistant Professor and Livestock Bioenvironmental Engineer, University of Nebraska – Lincoln aschmidt@unl.edu

Nicole R. Schuster, Graduate Research Assistant, University of Nebraska – Lincoln; Julie Peterson, Assistant Professor and Entomologist, University of Nebraska – Lincoln

Additional information

Dr. Amy Millmier Schmidt; (402) 472-0877; aschmidt@unl.edu

Acknowledgements

We would like to recognize a number of individuals who assisted with soil sample collection, arthropod extractions, and other laboratory activities over the course of this project, including Keith Miller, Ethan Doyle, Mitch Goedeken, Eric Davis, Lucas Snethan, Kevan Reardon and Kayla Tierramar

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. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Environmental Benefits of Manure Application

For centuries, animal manure has been recognized as a soil “builder” because of its contributions to improving soil quality. Environmental benefits are possible from manure application if manure and manure nutrients are applied and timing and placement follows best management practices. When compared to more conventional fertilizer, manure properly applied to land has the potential to provide environmental benefits including:

  • Increased soil carbon and reduced atmospheric carbon levels
  • Reduced soil erosion and runoff
  • Reduced nitrate leaching
  • Reduced energy demands for natural gas-intensive nitrogen(N) fertilizers

Manure Effects on Soil Organic Matter

Manure contains most elements required for plant growth including N, P, potassium, and micronutrients (Manure as a Source of Crop Nutrients and Soil Amendment). However, it is manure’s organic carbon that provides its potential environmental value. Soil organic matter is considered nature’s signature of a productive soil. Organic carbon from manure provides the energy source for the active, healthy soil microbial environment that both stabilizes nutrient sources and makes those nutrients available to crops. More…

Manure is comparable to commercial fertilizer as a plant food and, if applied according to a sound nutrient plan, has environmental benefits over commercial fertilizer. cc2.5 manure nutrient management group

Several long-term manure application studies have illustrated its ability to slow or reverse declining soil organic levels of cropland:

The ability of manure to maintain or build soil organic matter levels has a direct impact on enhancing the amount of carbon sequestration in cropped soils.

Manure organic matter contributes to improved soil structure, resulting in improved water infiltration and greater water-holding capacity leading to decreased crop water stress, soil erosion, and increased nutrient retention. An extensive literature review of historical soil conservation experiment station data from 70 plot years at 7 locations around the United States suggested that manure produced substantial reductions in soil erosion (13%-77%) and runoff (1%-68%). Increased manure application rates produced greater reductions in soil erosion and runoff. More… Additional studies during years following manure application suggest a residual benefit of past manure application. More…

Overview of Manure Impacts on Soil (Mark Risse, University of Georgia). Visit the archived webinar for additional videos on carbon, fertility, and soil health.

 

Manure Effects on Soil Erosion

 

In addition, surface application of manure behaves similarly to crop residue. Crop residue significantly decreases soil erosion by reducing raindrop impact which detaches soil particles and allows them to move offsite with water runoff. Data has been published showing how manure can coat the soil surface and reduce raindrop impact in the same way as crop residue. More… Therefore, in the short-term, surface manure applications have the ability to decrease soil erosion leading to a positive impact on environmental protection.

Organic Nitrogen

In addition, organic N (manure N tied to organic compounds) is more stable than N applied as commercial fertilizer. A significant fraction of manure N is stored in an organic form that is slowly released as soils warm and as crops require N. Commercial fertilizer N is applied as either nitrate or an ammonium (easily converted to nitrate). Nitrate-N is soluble in water and mobile. These forms contribute to leaching during excess precipitation (e.g., spring rains prior to or early in growing season) or irrigation. Manure N’s slow transformation to nitrate is better timed to crop N needs, resulting in less leaching potential. In fact, manure N is a natural slow-release form of N.

Energy Benefits

Recycling of manure nutrients in a cropping system as opposed to manufacturing or mining of a new nutrient resource also provides energy benefits. Commercial nitrogen fertilizers consume significant energy as a feedstock and for processing resulting in greenhouse gas emissions. More… Anhydrous ammonia requires the equivalent of 3300 cubic feet of natural gas to supply the nitrogen requirements of an acre of corn (assuming 200 lb of N application). Phosphorus and potassium fertilizers also have energy requirements for mining and processing. Substituting manure for commercial fertilizers significantly reduces crop production energy costs

It is important to remember that the environmental benefits of manure outlined in this article are only beneficial when best management practices for reducing soil erosion are implemented in concert with proper levels of manure nutrient application and use.

Recommended Reading on Environmental Benefits of Manure

Authors: Rick Koelsch, University of Nebraska, and Ron Wiederholt, North Dakota State University Reviewers: Charles Wortmann, University of Nebraska, and Steve Brinkman, Iowa NRCS