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

2014 Annual 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. S. Chris Reberg-Horton
North Carolina State University

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

Summary

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.

Objectives/Performance Targets

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

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

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

Accomplishments/Milestones

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.
  • 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:

o  Cruz, Angel – M.S.  2013.  Does Diversity Matter?  Examining Agroecosystems Impacts of Beneficial Soil Microorganisms Diversity. 

o  Chen, Huaihai – Ph.D.  2014. Fungal Nitrous Oxide Production in Agro-ecosystems: Importance Relative to Bacteria and Responses to Abiotic Factors. 

o  Monthapo, Nape – Ph.D.  2013. Fungal Potential in Soil Nitrous Oxide Production and its PH and Moisture Dependence in Diverse Managed Ecosystems. 

  • Graduate student publications:

o  Nape V. Mothapo, Huaihai Chen, Marc A. Cubeta, Wei Shi.  2013.  Nitrous oxide producing activity of diverse fungi from distinct agroecosystems.  Soil Biology and Biochemistry.  66:94-101.

o  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.

o  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.

o  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

o  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.

o  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:

o  A.M. Knight, W.J. Everman, S. Reberg-Horton, and S. Hu. 2014. IMPACT OF WEED MANAGEMENT SYSTEMS ON GREENHOUSE GAS EMISSIONS. Proc. NorthEastern Weed Sci. Soc. 68:32.

o  A.M. Knight, W.J. Everman, S. Reberg-Horton, and S. Hu. 2014. IMPACT OF WEED MANAGEMENT SYSTEMS ON GREENHOUSE GAS EMISSIONS. Proc. South. Weed Sci. Soc. 67:47.

o  A.M. Knight, W.J. Everman, S. Reberg-Horton, and S. Hu. 2014. IMPACT OF WEED MANAGEMENT SYSTEMS ON GREENHOUSE GAS EMISSIONS. Proc. Weed Sci. Soc. Amer. 54:300.

o  A.M. Knight, W.J. Everman, S. Reberg-Horton, S. Hu, D.L. Jordan and N. Creamer. 2014. IMPACT OF LONG TERM PRODUCTION SYSTEMS ON GREENHOUSE GAS EMISSIONS. Proc. of Amer. Soc. of Agron.

o  X.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.

Impacts and Contributions/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 are currently hosting four new graduate students and two new scientists (Wayne Robarge and Alan Franzluebbers) on the greenhouse gas project who have not been part of the FSRU research team previously.  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.