CEFS Long-Term Systems Research: Providing the Building Blocks for Resilient Food Production Systems

Final Report for LS12-247

Project Type: Research and Education
Funds awarded in 2012: $300,000.00
Projected End Date: 12/31/2015
Region: Southern
State: North Carolina
Principal Investigator:
Dr. Chris Reberg-Horton
North Carolina State University
Expand All

Project Information


The Long-Term Farming System Research trial (FSRU) at the Center for Environmental Farming Systems (CEFS) was initiated in 1999 and comprises more than 200 acres with 5 different systems replicated 3 times. The objectives for initiating this trial 16 years ago were to research: 1) how the various systems impact long-term sustainability of soil and water resources, 2) whether some systems are more resilient to perturbations in weather, input and market prices, and 3) how the systems impact biodiversity, wildlife, pest dynamics and the ecological services of farmland. Our study is designed to provide a better understanding of how different systems interact with and impact the natural resource base and economic viability of farms, as well as identify alternative approaches with potential for synergistic effects, such as diversification, access to direct markets, and environmental conservation.

Over time the FSRU systems experiment has become irreplaceably unique for several reasons. First is the comprehensive nature of the systems being studied and their relevancy in the South. Second, the scale (200 acres) and large plot size gives us the ability to study important production system dynamics (e.g., insect and disease management) that others cannot, making our results more relevant to producers. We are also a model of inter-institutional collaboration with involvement of various departments and colleges at each 1890 and 1862 Land Grant university, the NC Department of Agriculture and Consumer Services, and NGOs as diverse as Carolina Farm Stewardship Association and the NC Farm Bureau. Our systems experiment has also integrated outreach at every level with farmer involvement in both research and educational programming.

Project Objectives:

How systems impact long-term sustainability of soil and water resources,

system differences in resilience to perturbations in weather, inputs and market prices, and

how systems impact biodiversity, pest dynamics and ecological services of agriculture.


Research results and discussion:
  • Interviewed 30 fresh fruit and vegetable growers about their perceptions and motivations for selling produce to low-income consumers. We've also interviewed about 25 row crop growers about their decision making when it comes to environmental practices and organic certification; we plan to conduct 5 more, and use the results to design a survey to learn more about the land tenure/contract issue and how it affects growers' decisions.
  • Agroforestry experiment has made the transition from a tree-crop system to a silvopasture system. Native warm-season grasses were successfully established and tree growth has been rapidly increasing.  Several embedded research projects were established in this long-term experiment, including measurement of (a) greenhouse gases from soil as a function of location in the agroforestry design, (b) native warm-season grass establishment with disking and no-tillage seedbed preparation, (c) incoming solar radiation as affected by position in the system, and (d) soil organic carbon and nitrogen as affected by distance from trees.
  • Integrated-crop animal treatment has received two embedded treatments in the transition from pasture to cropping phase. Pasture termination method (plow, disk, and no-tillage) is being evaluated in 2016 for effects on crop growth and soil organic carbon and nitrogen fractions.  Nitrogen fertility of the pasture-crop rotation is being investigated during corn production in 2016.
  • Hosted “Soilbration” at CEFS to celebrate 20 years of sustainable agricultural research. By collaborating with the Natural Resources Conservation Service, we were able to host almost 500 participants at the event.
  • Co-sponsored climate change conferences with the Abundance Foundation three years in a row. Multiple scientists from our group have presented.
  • Hosted 15-20 sustainable agriculture workshops each year at CEFS.
  • We measured three fractions of soil labile organic matter among four treatments after amendments (manure in organic, UAN fertilizer in conventional). Potassium permanganate oxidizable carbon (POX-C) increased with decreasing tillage among organic treatments, while no-till management in the conventional treatment maintained residual labile organic matter despite receiving no organic inputs.  A similar trend is followed by microbial biomass carbon and nitrogen.
  • Soil N2O production rates differed significantly among systems, fungal contribution accounted consistently for > 30% of total soil N2O production. Fungal ability of N2O production has been increasingly documented, yet its ecological importance and controlling factors remains unclear.  Our result indicated that fungi could play an important role in soil N2O production in diverse ecosystems and soil pH is a critical control factor.
  • Invertebrate predator/prey ratios vary substantially amongst systems with surprisingly low ratios in our crop/animal systems where perennial hay and pasture is rotated with row crop production. Preliminary results indicate invertebrates play an important role in residue decomposition rates that may in turn impact greenhouse gas emissions.
  • As an extension of the project to discern effects on soil and productivity responses, an agroforestry experiment has been maintained with funding from US-Forest Service and USDA-Agricultural Research Service. This study is transitioning from alley-cropping to silvopasture, and therefore, will allow us to characterize both forestry and agriculture in the same system.
  • Houghton, S., O’Sullivan, J., Simon, M., & Stewart, A. (2013). How is it that NC tobacco farmers are deciding to plant organic crops? Sharing our theories when they are square pegs for round holes. Paper presented at the Annual Meetings of the Academy of Management, Orlando, FL, 9 – 13, August.
  • A group of 5 agricultural extension agents from “Instituto Ouro verde” in Brazil visited the FSRU on 3/30/15. The purpose of the visit was for them to know the FSRU, exchange experiences about resilient agriculture, and create connections for potential future collaboration.  
  • A group of about 15 people from various programs of the Center for Environmental Farming Systems (CEFS) visited the FSRU on 5/6/2015. The objective of the visit was to inform other CEFS member about the FSRU in general.     
  • A group of 5 member of NCSU-Entomology group visited the FSRU on 5/18/15. The purpose was to have a general tour of the research station with focus on sustainability.
  • As part of the 2015 CEFS Internship program, a group of 15 undergrad and graduate student visited the FSRU on 6/9/2015. The purpose was for the students to know about the various programs and research opportunities that the FSRU offers to students and researches.
  • We are finishing surveys of farmers using a range of conservation practices. So far, the largest explanatory variable has been the stability of their land tenure.  Farmers predominantly on land with short-term leases are reluctant to invest in conservation practices where the return to investments in soil and water conservation practices accrue slowly.  A new collaborator, Dara Bloom, has joined the team to conduct research on how land tenure impacts sustainability.
  • Graduate student theses completed:
    • Bloszies, Sean – Ph.D. 2015  Microbial activity and greenhouse gases production from the soil.
    • Adams, Paul – M.S. 2015. "Above and Below Ground Biological Interactions in Corn (Zea Mays) and Soybean (Glycine max) under Various Agriculture Production Systems".
    • Ross, Natalie – M.S. 2016. “Development and Application of a Continuous Flow-Through Chamber Technique to Measure Nitrous Oxide Emissions from Agroecosystems in the Southeast”
    • Knight, Alexandra – Ph.D. 2016. “Greenhouse Gas Emissions in Long Term Agricultural Production Systems”.
    • Cruz, Angel – M.S.   Does Diversity Matter?  Examining Agroecosystems Impacts of Beneficial Soil Microorganisms Diversity. 
    • Chen, Huaihai - Ph.D. Fungal Nitrous Oxide Production in Agro-ecosystems: Importance Relative to Bacteria and Responses to Abiotic Factors. 
    • Monthapo, Nape – Ph.D. Fungal Potential in Soil Nitrous Oxide Production and its PH and Moisture Dependence in Diverse Managed Ecosystems. 
  • Publications:
    • Franzluebbers, A.J. 2015. Farming strategies to fuel bioenergy demands and facilitate essential soil services. Geoderma 259-260:251-258.
    • Franzluebbers, A.J. 2016. Should soil testing services measure soil biological activity? Agric. Environ. Letters 1:150009, doi:10.2134/ael2015.11.0009.
    • Atwell, R.A. and S.C. Reberg-Horton.   Row spacing and seeding rate effects on canola population, weed competition, and yield in winter organic canola production.  Agronomy Journal (Accepted).
    • Wells, M.S., S.C. Reberg-Horton, S.B. Mirsky, J.E. Maul, and S. Hu. 2016. In situ validation of fungal N translocation to cereal rye mulches under no-till soybean production. Plant and Soil. doi:10.1007/s11104-016-2989-8
    • Wells, M.S., S.C. Reberg-Horton, and S.B. Mirsky. 2016. Delayed planting for improved soil water management in cover crop-based no-till corn production. Agron. J. 108:1-9.
    • Wells, M.S., C. Brinton, and S.C. Reberg-Horton. Weed suppression and soybean yield in a no-till cover-crop mulched system as influenced by six rye cultivars. Renewable Agriculture and Food Systems, available on CJO2015. doi:10.1017/S1742170515000344
    • Nape V. Mothapo, Huaihai Chen, Marc A. Cubeta, Wei Shi.   Nitrous oxide producing activity of diverse fungi from distinct agroecosystems.  Soil Biology and Biochemistry.  66:94-101.
    • Huaihai Chen, Nape V. Mothapo, Wei Shi. 2014 The significant contribution of fungi to soil N2O production across diverse ecosystems. Applied Soil Ecology.  73:70-77.
    • Fox, AF, Reberg-Horton SC, Orr DB, Moorman CE, Frank SD. 2013 Crop and field border effects on weed seed predation in the southeastern U.S. coastal plain. Agriculture, Ecosystems & Environment. 177:58–62.
    • Moorman CE, Plush CJ, Orr DB, Reberg-Horton C. 2013. Beneficial Insect Borders Provide Northern Bobwhite Brood Habitat. PLoS ONE 8(12): e83815. doi:10.1371/journal.pone.0083815
    • Moorman, C. E., C. J. Plush, D. Orr, C. Reberg-Horton, and B. Gardner. 2013. Small mammal use of field borders planted as beneficial insect habitat. Wildlife Society Bulletin 37:209-215.
    • Plush, C. J., C. E. Moorman, D. Orr, and C. Reberg-Horton. 2013. Overwintering sparrow use of field borders planted as beneficial insect habitat. Journal of Wildlife Management 77:200-206.
  • Presentations at academic conferences:
    • Ross, N., W. Robarge, S.C. Reberg-Horton and J. Grossman.   Development of a Continuous-Flow Chamber Technique to Measure Nitrous Oxide Emissions from Agroecosystems in the Southeast. Proc. of Amer. Soc. of Agron.
    • Knight, A. M., W.J. Everman, S. Reberg-Horton, and S. Hu, D.L. Jordan and N. Creamer. 2015. Nitrous Oxide Emissions in Long Term Cropping Systems. Proc. of Amer. Soc. of Agron.
    • Knight, A. M., W.J. Everman, S. Reberg-Horton, and S. Hu, D.L. Jordan and N. Creamer. 2015. Nitrous Oxide Output Based on Weed Management Systems. Proc. of Weed Sci. Soc. of Amer. (119).
    • Knight, A. M., W.J. Everman, S. Reberg-Horton, and S. Hu, D.L. Jordan and N. Creamer. 2015. Nitrous Oxide Emissions Impacted by Weed Management. Proc. of South. Weed. Sci. Soc. (133).
    • Atwell, R.A., S.B. Mirsky, H. Poffenbarger, and S.C. Reberg-Horton. (2015). Cover crop mixture proportion and starter fertilizer effects on weed competition and yield in organic rotational no-till maize production. In 2015 annual meeting abstracts. ASA/CSSA/SSSA, Minneapolis, MN. Oral Presentation.
    • Atwell, R.A., S.C. Reberg-Horton, S.B. Mirsky, M.S. Castillo, and R.J. McGee. (2015). Identifying regionally adapted winter pea genotypes that maximize grain, forage, and cover crop potential in the southeast USA. In 2015 annual meeting abstracts. ASA/CSSA/SSSA, Minneapolis, MN.
    • Pershing, M.R., C. Crozier, M. Shroeder-Moreno, D.L. Osmond, A.J. Franzluebbers. 2015. Flush of CO2 as a short-term biological indicator of soil nitrogen mineralization in the southeast. Ann. Mtg. Am. Soc. Agron., Crop Sci. Soc. Am., and Soil Sci. Soc. Am., Minneapolis, MN, 15-18 November 2015.
    • Michelle Schroeder. “Sustainable Ag and Long Term Farming Research at CEFS and NCSU”.  University of Zagreb, Croatia.  Dec 9, 2015. 
    • L. Zhang, C. Tu, Y.P. Qiu, S.C. Reberg-Horton and S. Hu. 2014. Arbuscular mycorrhizal fungi markedly reduce N2O emissions from an organic soil. 99th Annual meeting of Ecological Society of America. Sacramento, August 10-15, 2014.
Participation Summary

Project Outcomes

Project outcomes:

CEFS Farming System Research Unit has been identified as an ideal location to test how different cropping systems compare in terms of greenhouse gas emissions, particularly N2O.  Biogeochemists consider that one of agriculture’s largest roles in greenhouse gas emissions is via N2O emission, which on a molar basis has 310 times the global warming potential of CO2.  Reliable comparisons of greenhouse gas emissions require what FSRU has to offer, i.e. a replicated systems trial at least ten years old with ample data on individual components of the systems.  We hosted six graduate student theses on the topic of greenhouse gases and two new scientists on the topic, Wayne Robarge and Alan Franzluebbers.  CEFS is also working with Environmental Defense Fund to incorporate our results into a national model of N2O emissions, particularly to revise estimates from the Southeast, which appear to be severely overestimated by the Midwestern models.

In addition to the greenhouse gas group, we continue to conduct the farming systems trial with adjustments to farm protocols to mimic the evolving farming systems in the region.  For instance, our trial has seen large increases in glyphosate-resistant Palmer Amaranth in the conventional treatments, but this weed remains infrequent in the organic systems.  We have shifted the conventional systems to greater use of pre-emergent herbicides, similar to most farmers in eastern North Carolina dealing with the evolution of this glyphosate-resistant weed.  A new collaborator, Wes Everman, is working with us to test the viability of new weed-seed-destroying machines that attach to combines and how effective they may be over the long term in both our conventional and organic treatments in nested subplots.  Both the experience with greenhouse gases and evolution of glyphosate resistance make an important point about the value of long-term cropping systems trials.  They are not just tools for testing a priori hypotheses, to which short-term experiments are tied.  They also generate hypotheses and serve as a platform for continuously answering questions that were initially unanticipated.

A new research direction in the social sciences is also taking shape with new collaborators Sarah Bowen and Dara Bloom (Sociology) and Kenrett Jefferson-Moore (Economics).  Combined, they are examining how the farming systems in our trial are being conducted around the state and what social and economic constraints determine farmers' choices of cropping system.  Findings so far suggest land tenure/contracting issues are playing an important role in attitudes towards conservation and a follow up survey is being designed around this issue.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.