Long-Term, Large-Scale Systems Research Directed Toward Agricultural Sustainability

Final Report for LS01-120

Project Type: Research and Education
Funds awarded in 2001: $230,000.00
Projected End Date: 12/31/2005
Region: Southern
State: North Carolina
Principal Investigator:
Dr. J. Paul Mueller
North Carolina State University
Expand All

Project Information

Abstract:

An 81 ha long-term, large-scale systems study was initiated in September of 1998 at the Center for Environmental Farming Systems located near Goldsboro, NC, USA. The experiment is currently in its 7th year. Data collected during the first 5-years of the trial indicate that the C inputs, the degree of soil disturbance and time of sampling have important effects on soil quality variables. Microbial biomass and retention of C and N in soils was highest in the least disturbed systems and systems with organic C inputs. Furthermore, nested short-term studies have contributed important information regarding transition strategies to organic production and weed biology and ecology. Another study found that natural and semi-natural habitats in the farm landscape are not necessarily associated with weed contamination of adjacent crop fields.

Project Objectives:

1.) Evaluate the transitional changes that will begin manifestation during years 4-6 on the five, diverse systems: three agricultural, a successional and a plantation forestry system.

2.) Expand the scope of the experiment beyond the initiation phase by nesting other experiments within the larger system.

3.) Strengthen existing innovative educational programs by elaborating the intensive internships in sustainable agriculture for undergraduates, field days, tours, faculty visits and a web site.

Introduction:

Systems are characterized by behavior as whole in response to stimuli to any part. Whole systems possess qualities that are not contained in their individual components (Ikerd, 1993). Nevertheless, for purposes of experimentation, individual plants and fields have historically been considered the fundamental units for applied agricultural research. Farming systems, on the other hand, represent a level of research focus which considers fields as components of farms from which economic and sociological analyses can be performed (Loomis and Connor, 1992). Because of their complex nature and far-reaching implications, systems experiments tend to be designed for the long-term (Southwood 1994). These long-term studies (such as those carried out at Rothamsted) are sometimes the only sources of insight regarding the mechanisms of environmental change that impact agriculture (Poulton 1996). Long-term experiments are essential in determining most soil-related factors affecting the sustainability of production.

Systematic collection of information that characterizes system performance provides insights into critical performance parameters (and their interactions) leading to the possibility of predicting outcomes. Urban citizens, noting the significant investment of tax dollars in agriculture, are demanding production systems more responsive to their environmental concerns. For example, the current moratorium on the expansion of new hog production facilities in North Carolina was initiated by pressure from urban citizens. The Center for Environmental Farming Systems (CEFS) is an 810 hectare (2000 acre) facility established in 1994 as a partnership between North Carolina’s two Land Grant Universities, North Carolina State University, North Carolina Agricultural and Technical State University, and the North Carolina Department of Agriculture and Consumer Services. The Farming Systems Research Unit at CEFS is one of five CEFS units and is designated as a site to conduct long-term, large-scale systems experiments and demonstrations. Criteria for research to be conducted at CEFS have been developed, and include: a) farmers and other stakeholder groups must be a part of the research planning process, b) studies must be interdisciplinary and systems-oriented, and c) agricultural problems are addressed on a farm-scale. With initial funding from SARE southern region, a unique systems experiment was established in 1998 to assess, over the short and long terms, biological, environmental and economic processes and the relationships among them. This system experiment was the result of four years of intense planning and coalition-building by the CEFS team. The team includes research faculty representing ten departments in the College of Agriculture and Life Sciences (CALS) at NCSU, NCA&TSU, NCDA&CS; extension agents; individuals from many of North Carolina=s agriculture-based, non-profit organizations and farmer groups (Carolina Farm Stewardship Association, Rural Advancement Foundation International-USA, North Carolina Farm Bureau Federation, American Livestock Breeds Conservancy); conventional, transitional, and organic farmers; and staff from state and federal agencies that are involved with agriculture. Farmers have contributed in a substantive way to the process by stimulating fresh approaches to integrating the functions of the Land Grant Universities.
Research on FSRU involves examining agricultural management effects on diverse agriculture/ecosystems: a best management practice (BMP) system; an integrated crop/animal system; an organic production system; a forestry/woodlot system; and a successional ecosystem. We have used soil quality measurements (physical, chemical and biological) to characterize and define management factors contributing to soil degradation. Data (a sub-set reported here in Table 3.) were collected for soil physical properties (bulk density, aggregate stability, soil water characteristics, pore size distribution, hydraulic conductivity), soil chemical properties (pH, infiltration, organic matter, inorganic and total N) and biological properties (carbon dioxide (C02) evolution and microbial biomass, bacteria, entomopathogenic nematodes), weed populations (species and distribution), disease incidence (including disease-suppressive soils), insect dynamics (beneficials and pests), plant growth, development, biomass, yield and economic parameters. The strategy was to gather a minimum data set of soil quality indicators, measured collectively to elucidate changes within the soil ecosystem. Plots were sampled each year on multiple occasions depending on the variables measured (Table 3). While designed to continue for perpetuity, the experiment is currently only in its seventh year and systems differences are just beginning to emerge.
Nested research within the long term experiment continues to grow as faculty and graduate student involvement increases.

*Note: see references in Results and Discussion section

All Tables and Figures mentioned in this report
are on file in the Southern SARE office.
Contact Sue Blum at 770-229-3350 or
sueblum@southernsare.org for a hard copy.

Cooperators

Click linked name(s) to expand
  • Mary Barbercheck
  • Nancy Creamer
  • Michael Linker
  • Frank Louws
  • Charles Raczkowski

Research

Materials and methods:

Experimental Design

The design is a randomized complete block consisting of three replications of five systems. Approximately 81 ha have been divided, based on intensive soil mapping, into 3 diverse agriculture production systems, a successional ecosystem and a plantation forestry system. Individual plots range in size from 0.81 to 4.1 ha. Blocking was done by soil type, such that all samples in a system were taken from the same diagnostic soil in a given replication. The agricultural production systems include a conventional system using all the best management practices currently used by farmers (BMP), an integrated crop/animal system, and an organic system. The BMP system is split into till and no-till subplots and the Crop Animal is divided into three subplots each representing a different entry point in a 15-year rotation (Table 1).

In March 1999, five stratified random sampling points were selected for all future sampling in each plot. These points were physically marked, then geo-referenced using a Trimble backpack GPS unit and stored on a GIS database. Baseline soil sampling was conducted in March 1999 before the first cropping season. Data (a sub-set reported here in Table 2.) were collected for soil physical properties (bulk density, aggregate stability, soil water characteristics, pore size distribution, hydraulic conductivity), soil chemical properties (pH, infiltration, organic matter, inorganic and total N) and biological properties (carbon dioxide (C02) evolution and microbial biomass, bacteria, entomopathogenic nematodes), weed populations (species and distribution), disease incidence (including disease-suppressive soils), insect dynamics (beneficials and pests), plant growth, development, biomass, yield and economic parameters. The strategy was to gather a minimum data set of soil quality indicators, measured collectively to elucidate changes within the soil ecosystem. Plots were sampled each year on multiple occasions depending on the variables measured (Table 2.). Specific methods for data collected are reported in each section.

Research results and discussion:

Soil Quality Parameters

After the first two years of the study few differences in soil chemical properties were evident among the systems. After three years no differences were found between systems for field capacity, hydraulic conductivity, plant-available water retention and soil microporosity (Table 3). Bulk density was lowest in the organic (ORG), a system that is tilled for the production of organic crops, and highest in the crop/animal pasture (C/A-p), a non-tilled environment compacted by the grazing activity of animals. No differences in bulk density were found between the best management practices (BMP-nt), the woodlot (FOR-bw) and the old-field (SUCC) systems. The soil total porosity data followed the same trend as the soil bulk density data. Interpretation of the distribution of pore space into macro- and microporosity reveals that changes occurring in total porosity resulted from changes in macroporosity. The hydraulic conductivity trend was consistent with the soil macroporosity data but no significant differences were found between systems.
CO2 evolution was measured as an indicator of microbial activity. In general, greater CO2 evolution was measured in spring vs. fall, most notably for sub-plots in the wood-lot (FOR-bw), crop/animal (C/A-p), and for the old-field (SUCC) system. CO2 evolved in the best management practices (BMP-nt) sub-plot was approximately two-fold greater than the conventional tillage (BMP-ct) sub-plot (490 vs. 240 kg C/ha/day) at the spring sampling date and only 18% greater (444 vs. 376 kg C/ha/day) by fall. The crop/animal– pasture (C/A-p) sub-plot was similar to the BMP-nt sub-plot in the spring, with intermediate values ranging from 160 to 280 kg C/ha/day observed for organic (ORG), crop/animal (C/A-p), wood-lot (FOR-bw), and old-field (SUCC) systems. Infiltration, measured as the time required for 2.54 cm of water to move into the soil, was more rapid in the organic (ORG) system during spring and fall sampling periods compared to all other systems. This reflects the reliance on cultivation as the primary weed management tool in organic production. After several years, these results continue to indicate a greater level of microbial activity in systems where previous crop/plant residues are maintained on the surface or where animal manures constitute part of the soil fertility regime.

Structure in Six Managed Ecosystems

Ecosystem management practices profoundly impact the biomass, community structure and functioning of soil microbes, which in turn modify various ecosystem processes such as decomposition and nutrient cycling. Six sub-plots of the overall farming systems were selected for more intensive study. The six adjacent and replicated ecosystems included: old-field (SUCC), wood-lot (FOR-bw), crop/animal pasture (C/A-p), organic (ORG), and best management practices (BMP-ct and BMP-nt). After three years, soil microbial biomass and activity diverged (p < 0.05) (Zhang et al. 2005), with microbial biomass and microbial activity being significantly higher in the organic system (ORG) than in the conventional (BMP-ct) one (Tu et al. 2006). Also, soil organic matter substantially increased (p = 0.09) (Tu et al. 2006). Microbial activity (heterotrophic respiration) was more sensitive than the total microbial biomass to changes in the management regimes. Analysis of phospholipid fatty acid (PLFA) composition of soil microbes also showed divergence of the microbial community structure among the six ecosystems with high microbial diversity in organic and no-tillage systems (Table 4). Fungal contribution to the total microbial biomass and fungal to bacterial ratios increased with decreasing disturbance intensity except in the crop/animal (C/A-p) pasture system (Table 4). Increased fungal contribution coincided with a decrease in microbial respiration in ecosystems under low disturbance intensity. These results suggest that intensive perturbations such as tillage and fungicides have more significant effects on fungi than bacteria. Therefore, reduction or elimination of those practices favors fungi over bacteria, altering the structure of the microbial community.

Soil Nematodes and Micro arthropods

Soil samples were stored at 15 C and processed within three weeks after the sample date. A 500-cm3 sub-sample was processed by elutriation and centrifugation to extract nematodes from soil. Roots were collected from a sieve on the elutriator and placed in a mist extractor for 5 days to extract nematodes from roots and organic debris (Barker et al., 1986). Analyses were conducted on transformed (log10 [x +1]) nematode numbers to standardize the variance and untransformed numbers are presented for clarity.

Numbers of bactivores and fungivores were greater (P = 0.05) in organic than in conventional systems in July, but not at other dates in 2001 (Table 5.).
Higher densities of these free-living nematodes are probably a result of applications of organic sources of nitrogen including a winter cover crop.

Three species of beneficial insect-parasitic nematodes, Steinernema carpocapsae, S. glaseri and Heterorhabditis bacteriophora, and two genera of insect-pathogenic fungi, Beauveria and Metarhizium, were isolated from the site. Total mean entomopathogenic nematode abundance from 1999-2002 was greater in the Succ plots than in the BMP-ct, ORG, and C/A-pasture sub-plots but not different from BMP-nt, and FOR-bw (table 9). S. carpocapsae, which tends to occur near the soil surface, appears to have been most severely affected by soil disturbance, e.g., by tillage in the organic and conventional tillage treatments, and by compaction in the pasture system. H. bacteriophora, which tends to move throughout the soil profile, was more abundant in the BMP-ct than nt sub-plots. S. glaseri was equally abundant across all systems. Insect-parasitic fungi were rarely detected compared with the detection of insect-parasitic nematodes. Metarhizium anisopliae was more commonly detected than Beauveria bassiana. Detection in all systems was similar, except for the pasture sub-plot, in which M. anisopliae was detected at about 2 to 5 times the frequency as in other systems. Because these nematodes and fungi are parasites of soil arthropods, their occurrence in any treatment would be affected by both the abiotic conditions created by the treatment, and the biotic conditions, e.g., the availability of suitable host arthropods.

Microarthropods enhance microbial activity, accelerate decomposition, and mediate transport processes in soil. Cumulative abundance of soil microarthropods was greater in the organic (ORG), than in the BMP-ct, FOR-bw and pasture C/A-p sub-plots, but not different from BMP-nt and successional (SUCC) treatments (table 9). This pattern was driven by the abundance of soil mites, which comprised about 70% of the sampled arthropod community. Collembola and all other arthropods comprised about 20 and 10% of the soil arthropod community, respectively. Soil compaction in the pasture system may have contributed to the low numbers of arthropods detected there. Collembola abundance was positively correlated with percentage sand and macroporosity (r2 = 0.4) and negatively correlated with percentage clay and microporosity (r2 = -0.4).

Time of sampling may affect conclusions as to which soil characteristics are most dominant and or important in measuring soil quality. These results can be used to determine indicators of ecosystem health. Over the three years of monitoring, differences among the various systems were only beginning to be expressed. Future research may be able to focus on identification of taxa to determine indicator species. One of the largest challenges in this work is the tremendous amounts of data generated. Analysis of these to identify informative taxa and best time of year to sample could help reduce the numbers of types of measures made.

Nested Studies

The long-term systems experiment was designed with large plots in part to allow the nesting of short-term experiments within the context of the overall experiment. For example, as we transitioned from conventional to organic production in the organic sub-plots, we nested a study to evaluate various strategies of making that transition. Likewise, several nested studies have been conducted as part of an ever-growing graduate student program. In one such study a graduate student in entomology is evaluating beneficial insect habitats, which are increasingly being employed by growers on small farms in the South.
The objectives of this nested research are to 1) determine what insects (beneficial or otherwise) are attracted to select cut flower crops, cover crops, and commercial beneficial seed blends; 2) examine the purity, germination and on-farm growth characteristics of these commercial seed blends; and 3) to construct and evaluate a simple beneficial insect habitat based on existing literature. Below are summaries from three additional nested studies.

Strategies for Transition to Organic Systems

Ecological and Economic Indices

In the transition from conventional to organic production systems, there often is a period of suppressed yields followed by a return to yields similar to conventional production. This “transition effect” has been attributed in part to time required for changes in soil chemical, physical, and biological properties that govern nutrient cycling, plant growth and development, and the biological control properties of the system (Scow et al., 1994; Wander et al., 1994; Reganold et al., 1993). While some studies have documented soil, biological, and economic changes that occur during transition, our study investigated a range of specific strategies aimed at a better understanding of the many interacting factors during this critical period.

The experiment is targeted at conventional growers in the Region who are hesitant about making an immediate and complete transition to organic agriculture. These growers seek to transition gradually as they learn and gain experience with organic management practices. Five strategies of transition are being evaluated and compared to a conventional control (1): immediate substitution of all conventional inputs with organic management practices and inputs (2); substitution of one of the major classes of inputs (fertilizer, herbicide, pesticides (insecticides & fungicides) in the first two years, followed by a third year where all classes of synthetic inputs have been replaced in an organic system (3-5); and gradual withdrawal of all classes of inputs over the three-year period (6) until an organic system is in place by the third year (Table 10).

The experiment had two ‘starts’ of the following rotation to ensure replication in time: soybean, sweetpotato, wheat/cabbage. Start 1 began in 2000 and Start 2 in 2001. A wide range of parameters are being measured, including: aboveground biomass of cover crop and cash crop, soil quality indices (physical, chemical, biological), plant residue decomposition, soil microbiological properties, insect, weed, disease incidence, crop yield, and economic returns.

Yield data for all harvests to date has been summarized but cannot be presented in its entirety due space limitations. Table 11 summarizes treatment yields as compared to conventional yields when combined across years, crops, and starts. Using organic fertility strategies (cover crops, composts, animal manures, soybean meal) produced crops with yields not significantly different from the conventional control.

Soil quality data collected showed that for the 1st start in the experiment, soil quality parameters were unaffected by treatment. Nevertheless, there was a trend for greater soil respiration (evolved CO2) and more rapid water infiltration in the organic compared to conventional systems. Likewise penetrometer resistance, a measure of soil compaction, tended to be greatest in the conventional system. The same pattern of results was evident in the 2nd start of the experiment, with a wheat/cabbage double crop, but with significant differences noted between the conventional and both organic/transitional organic treatments (data not shown).

Bacterial communities including Burkholderia, fluorescent pseudomonads, and total culturable bacteria were differentially impacted by both season and transition strategy. A consistent trend was found wherein populations were high in March, declined in the summer months, and rose again in September. Organic transition strategy was significant for Burkholderia in the first initiation of the treatments (Start 1), Pseudomonas populations in the second initiation of the treatments (Start 2), and the total culturable bacteria populations in Start 1. In these cases, the treatments receiving compost in place of synthetic fertilizer were often found to have the highest populations. Numbers of bacteria were consistently higher in Start 2 compared to the first year of Start1.
Microbial biomass and activity were more sensitive to changes in soil management practices than total C and N. In the first two years, the organic system was most effective in enhancing soil microbial biomass C and N among the transition strategies. By the third year, soil microbial biomass C and N in the reduced–input transition strategies were significantly greater than those in the conventional (averaging 32 and 35% higher, respectively), although they were slightly lower than those in the organic (averaging 13 and 17% lower, respectively). Soil microbial activity and net N mineralization in all transitional systems were significantly higher than those in the conventional (averagely 83 and 66% greater, respectively), with no differences among the various transition strategies. These findings suggest that the transitional strategies that gradually reduce chemical inputs can benefit microbial growth during the early stages of transition to organic farming systems.

Critical Weed-Free Period for ‘Beauregard’ Sweetpotato (Ipomoea batatas)

A nested experiment was conducted to determine the critical weed free period for organic sweetpotatoes (Seem et al, 2003). Treatments included allowing weeds to grow for 2, 4, 6, or 8 wk after sweetpotato transplanting prior to weed removal, and maintaining the sweetpotato planting weed-free for 2, 4, 6, or 8 wk after transplanting prior to allowing weeds to grow. A weedy and weed-free control was also included in the study. These treatments were used to determine how long weeds can compete with sweetpotato without reducing yield, and how long sweetpotato must grow before yield is unaffected by newly emerging weeds. Data indicated that sweetpotato may gain a competitive advantage over weeds when planting is delayed. At both planting dates, it was found that if weeds were eliminated during a critical period of 2 to 6 wk after transplanting, yields were not affected (data not shown).

The Association of Weed Species Richness and Abundance with Field Margin Type in Crop Fields

A third nested study evaluated the relationship between weedy plant populations in field margins and weed populations in neighboring crop fields (Jelinek, 2004). Natural vegetation on farms such as field margins, fallow fields and wooded areas provide increased biodiversity, structural diversity, habitat for wildlife and beneficial insects, and can act as protective buffers against agrochemical drift (Kleijn, 1997). Nevertheless, farmers frequently view these areas as potential sources of weeds, pests, and diseases. The relationship between managed and unmanaged field margins and adjacent cropland was examined relative to diversity, abundance, and distribution of weedy species.

Weed species abundance was compiled by field, margin type (managed or unmanaged), transect, distance from the field edge, and sampling date. Species richness was determined for weed species in the crop field and for plants found in the field margin. To determine whether an association existed between weeds appearing in the field margin and presence in the crop field, weed abundance for each of ten dominant weed species in the crop field was converted to presence/absence data and combined with presence/absence data from the field margins. Data from ten dominant weed species were combined across sampling dates and used to test if margin type or presence in the field margin were predictors of presence of the weed in the crop field.

For total weed abundance within crop field, field effect was significant (p< 0.001), however, margin type was not (p=0.44). This indicates that there were no differences between total abundance of weeds in crop edges adjacent to managed and unmanaged field margins. Distance effect was also significant (p< 0.001) indicating that total abundance of weeds differed depending on their location along the transect from field edge to the middle of the crop field.

Species richness for weeds in the crop field along the two field margin types differed (p= 0.03). Crop edges along managed field margins tended to have greater mean number of weed species (7.35) than unmanaged margins (6.55). It is not certain how biologically important this difference may be for agroecosystems.

This research supports the hypothesis that natural and semi-natural habitats
in the farm landscape are not necessarily associated with weed contamination of fields. Farms contain two dynamic ecosystems, managed and natural, that interact in positive and negative ways. To more fully recognize the benefits of such interactions, farms should be managed on landscape as well as field levels.

References

Barker, K. R., Townshend, J. F., Bird, G. W., Thomason, I. J., and Dickson, D. W. 1986. Determining nematode population responses to control agents. Pages 283-296 in: Methods for Evaluating Pesticides for Control of Plant Pathogens. K. D. Hickey, ed. American Phytopathological Society Press, St. Paul, MN.

Brownie, C., Bowman, D.T., and Burton, J.W. (1993). Estimating spatial variation in analysis of data from yield trials. A comparison of methods. Agronomy Journal 85, 1244 1253.

Ikerd, J. E. 1993. The need for a systems approach to sustainable agriculture. Agriculture, Ecosystems and Environment. 46:147-160.

Jelinek, S. 2004. MS Thesis NC State University. The Association of Weed Species Richness and Abundance with Field Margin Type.

Kleijn, D. 1997. Species richness and weed abundance in the vegetation of arable boundaries. PhD thesis, Wageningen Agricultural University. Wageningen, Netherlands 177p.

Leigh, R. A. and A. E. Johnston (Ed.). 1994. Long-term Experiments in Agricultural and Ecological Sciences. CAB International, UK.

Loomis, R. S. And D. J. Connor. 1994. Crop Ecology. Cambridge Univ. Press Melbourne.

Poulton, P. R. 1996. The rothamsted long-term experiments: Are they still relevant? Canadian J. Of Plt. Sci. 559-571.

Reganold, J.P., A.S. Palmer, J.C. Lockhart, and A. N. Macgregor. 1993. Soil quality and financial performance of biodynamic and conventional farms in New Zealand. Science. 260:344-349.

Scheiner, S.M. and J. Gurvitch. 1993. Design and Analysis of Ecological Experiments. Chapman & Hall, New York.

Scow, K.M., O. Somasco, N. Gunapala, S. Lau, R. Venette, H. Ferris, R. Miller, and C. Shennan. 1994. Transition from conventional to low-input agriculture changes soil fertility and biology. California Ag. 48:20-26.

Seem, J.E., N.G. Creamer, and D. W. Monks. 2003. Critical weed-free period for ‘Beauregard’ sweetpotato (Ipomoea batatas). Weed Technology 17:686-695.

Spedding, C. R. W. 1996. Agriculture and the citizen. Chapman & Hall, New York.

Southwood, T. R. E. 1994. The importance of long-term experimentation. In Long-term experiments in agricultural and ecological sciences. CAB International, Wallingford, UK.

Tu, C., F.J. Louws, N.G. Creamer, J.P. Mueller, C. Brownie, K. Fager, M. Bell, and S. Hu. 2005. Responses of soil microbial biomass and N availability to transition strategies from conventional to organic farming systems. Agriculture, Ecosystems & Environment. 113 (2): 206-215.

Wander, M.M., S.J. Traina, B.R.. Stinner, and S.E. Peters. 1994. Organic and conventional management effects on biologically active soil organic matter pools. Soil Sci. Soc. Am. J. 58:1130-1139.

Zhang W.J., W.Y. Rui, C. Tu, H.G. Diab, F.J. Louws, J.P. Mueller, N. Creamer, M. Bell, M.G. Wagger, S. Hu. 2005. Responses of soil microbial community structure and diversity to agricultural deintensification. Pedosphere 15, 440-447.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Outreach by CEFS faculty and students as well as the NCDA staff at CEFS has been excpetional this year. At CEFS alone over 480 people visited this year. The following is a list of some of the ways that we are meeting our objective to expand educational opportunities and community outreach.

February 2004: A soils workshop and visitors from Auburn University and the country of Moldovia (total visitors 75).

March 2004: North Carolina Agriculture Consultants Meeting and Extension Agent Training at the Organic Unit (total visitors 53).

April 2004: Class visit from Wayne Community College and Beef Advisory Board Meeting (total visitors 35).

May 2004: Vistors from Uruguay, NCSU vetinary students and Pasturland Ecology Class (total visitors 50)

June 2004: Sampson Community College, NRCS soil mapping workshop, Cattleman's Association meeting and Johnston County Ag. Extension Service field day "Johnston County Farm to Plate" (total visitors 119).

July 2004: Environmental Defense Fund tour, University of Louiana group dairy tour, visiting professors from Moldovia, and WB22 News piece and farm tour (total visitors 44).

August 2004: Eastern Carolina Medical Institute tour, a tour for beef producers from three eastern NC counties, videotaping of no-till agriculture equiptment for the horticulture department Oregon State University (total visitors 28).

September 2004: Freshman from the first engineering class at Eastern Carolina University (total visitors 30).

October 2004: Forestry students from Wayne Community College (total visitors 12).

Published in Scientific Journals

Casteel, M., J.P. Mueller, M.D. Sobsey, and M.C. Bell. 2005. Fecal Contamination of Agricultural Soils Before and After Hurricane-Associated Flooding in North Carolina. Journal of Environmental Science and Health Part A. 41:173–184, 2006.

Millar, L.C. and M. E. Barbercheck. 2001. Interactions between endemic and introduced entomopathogenic nematodes in conventional-till and no-till corn. Biological Control 22: 235-245.

Millar, L.C. and M. E. Barbercheck. 2002. Effects of tillage practices on entomopathogenic nematodes in a corn agroecosystem. Biological Control 25:1-11.

Mueller, J.P., M.E. Barbercheck, M.C. Bell, C. Brownie, N.G. Creamer, A. Hitt, S. Hu, L. King, H.M. Linker, F.J. Louws, S. Marlow, M. Marra, C.W. Raczkowski, D.J. Susko M.G. Wagger. 2002. Development and Implementation of a Long-Term Agricultural Systems Study: Challenges and Opportunities. HortTechnology. 12(3):362-368.

Seem, J., N.G. Creamer, and D.W. Monks. 2003. Critical weed-free period for ‘Beauregard’ sweetpotato (Ipomea batatas). Weed Technology. 17:686-695.

Treadwell, D.D., D.E. McKinney, N.G. Creamer. 2003. From Philosophy to Science: A Brief History of Organic Horticulture in the United States. HortScience. 38(5): 1009-1014. (Invited paper for 100th anniversary issue)

Tu, C., F.J. Louws, N.G. Creamer, J.P. Mueller, C. Brownie, K. Fager, M. Bell, and S. Hu. 2005. Responses of soil microbial biomass and N availability to transition strategies from conventional to organic farming systems. Submitted to Agriculture, Ecosystems & Environment. 113: 206–215.

Tungate K.D., D.J. Susko, and T.W. Rufty. 2002. Reproduction and offspring competitiveness of Senna obtusifolia are influenced by nutrient availability. New Phytologist 154: 661-669.

Zhang. W., J. Wu, C. Tu, H. G. Diab, F.J. Louws, J.P. Mueller, N.G. Creamer, M. Bell, M. G. Wagger and S. Hu. 2005. Divergence in soil microbial activity and community structure in six managed ecosystems along a disturbance gradient. Pedosphere. 15: 440-447

Submitted journal articles

Bell M.C, M.E. Barbercheck, L.D. King, F.J. Louws, M.G. Wagger . 2006. A multidisciplinary approach to assessing changes in the soil quality of diverse farming systems. Renewable Ag. and Food Systems. (In Review).

Forehand, L. J., D. B. Orr, and H. M. Linker. 2005. Evaluation of a commercially
available beneficial insect habitat for management of lepidoptera pests in
organic tomato production. Jour. Econ. Entomology. (In Review).

Treadwell, D.D., N.G. Creamer, D.W. Monks, and M.G. Wagger. 2004. A living mulch of buckwheat (Fagopyrum esculentum Moench) reduces weed density and biomass as a weed suppressive cover in sweet corn. Submitted to HortScience.

Abstracts

Barbercheck, M., M.C. Bell, C. Brownie, N.G. Creamer, F.Louws, L. King, S. Koenning, S. Hu, M. Linker, P. Mueller, C. Raczkowski, and M.G. Wagger. 2001. Soil ecology research at the Center for Environmental Farming Systems. Soil Ecology Society p.33 (abstr.).

Bell, M.C., M.E. Barbercheck, F.J. Louws, and M.G. Wagger. 2000. Quantitative and qualitative indicators of soil quality. Annual meeting abstracts/ASA-CSSA-SSSA (abstr.).

Burton, M.G. 2003. Careful mowing nearly eliminates sicklepod seedbank return in a short canopy crop. Proceedings of the annual meeting of the Northeastern Weed Science Society vol. 57 (abstr.).

Creamer, N.G. and J.P. Mueller. 2000. Implementation of Long-term Farming Systems Studies: Challenges and Opportunities. HortScience 35:517 (abstr.).

Creamer, NG, Finney D.M., and D.D. Treadwell. 2005. Organic Programs at The Center for Environmental Farming Systems. International Federation of Organic Agriculture Movements (IFOAM) in press.

Collins, A.A., D. C. Fargo, and F. J. Louws. 2002. Characterization of bacterial communities in soil during the transition to organic agriculture. Phytopathology 92:S16 (abstr.).

Collins, A.A. and F.J. Louws. 2001. Characterization of bacterial communities isolated from soils under diverse management practices. Phytopathology 91:S18 (abstr.).

Stout, R.D., M.G. Burton, and H.M. Linker. 2003. Comparison of Two Methods to Estimate Weed Populations in Field-Scale Agriculture. Proceedings of the annual meeting of the Northeastern Weed Science Society vol. 57 (abstr.). (Awarded 1st prize in graduate student poster competition.)

Treadwell, D.D. and N.G. Creamer. 2000. Intercropping Buckwheat and Sweet Corn: Competition and Management Factors. HortScience 35:507 (abstr.).

Tu, C., S. Hu, S.R. Koenning, and K.R. Barker. 2002. Root-parasitic nematodes impact microbial biomass and nitrogen mineralization in six soils. Annual meeting abstracts/ASA-CSSA-SSSA (CD-ROM version – abstr.).

Tungate K.D., K.A. Moyer, D.W. Israel, D.M. Watson, and T.W. Rufty. 2001. Mycorrhizal Colonization and growth of soybean and competing weed species at different temperatures. Annual meeting abstracts/ASA-CSSA-SSSA (CD-ROM version – abstr.).

Tungate K.D., D.J. Susko, and T.W. Rufty. 2000. Seed production and maternal effects with sicklepod grown in a low fertility environment. Annual Meetings of the Canadian Botanical Association (abstr.).

Wagger, M.G., N.G. Creamer, K.R. Baldwin, and P. Luna-Orea. 2000. Nitrogen release from summer annual cover crops. Annual meeting abstracts/ASA-CSSA-SSSA p.272 (abstr.).

Conference proceedings and presentations

Barbercheck, M. 2002. Response of Soil Organisms to Conventional and Alternative Agricultural Production Systems. Oral presentation at the National SARE Conference. 23-26 Oct 2002. Raleigh, NC.

Brownie, C. M.G. Wagger, S.V. Woolard, M.E. Barbercheck, M. Bell, N.G. Creamer, S. Hu, L. King, H.M. Linker, F.J. Louws, M. Marra, J.P. Mueller, and C.W. Raczkowski. Soil characteristic trends in the first two years of a long term study on the sustainability of agricultural systems. Oral presentation at the National SARE Conference. 23-26 Oct 2002. Raleigh, NC.

Jelinek, S.T., J.P. Mueller, N.G. Creamer, M.G. Burton, and C. Brownie. 2002. Natural Vegetation and Its Influence on Weed Populations in Neighboring Fields. Poster presentation at Carolina Farm Stewardship Association Sustainable Agriculture Conference. B15-17 Nov 2002. Boone, NC.

Kuminoff, N. and A. Wossink. 2005. Valuing the Option to Convert from Conventional to Organic Farming. Invited paper AAEA annual meeting, 24-27 July 2005. Providence, RI.

McKinney, D.E., N.G. Creamer, M.G. Wagger, and J.R. Schultheis. 2004. A preliminary study of dual use cover crops: sorghum sudangrass as both hay crop and summer cover crop for no-till, organic fall cabbage. Proceedings of the Southern Conservation Tillage Conference for Sustainable Agriculture. 5-7 June 2004. Raleigh, NC.

Moyer, K.A., D.M.H. Watson, K.D. Tungate, J.W. Burton, T.W. Rufty Jr. 2001. The involvement of mycorrhizae in nitrogen transfer between crop and weed species. Poster presentation at the annual meeting of Weed Science Society of America. Greensboro, NC.

Mueller J.P., M.E. Barbercheck, M.C. Bell, C. Brownie, N.G. Creamer, S. Hu, L. King, H.M. Linker, F.J. Louws, M. Marra, C.W. Raczkowski, D.J. Susko, M.G. Wagger. 2001. Desarrollo y Implementacion de un Estudio de Sistemas Agricolas al Gran Escala y Larga Duracion. I Simposio Internacional sobre Ganaderia Agroecologica. 6-8 Dec 2001. La Habana, Cuba.

Seem, J. 2001. Optimum weed-free period in sweetpotatoes. Yearbook of the North Carolina Vegetable Growers Association. 10 Dec 2001. Greensboro, NC.

Treadwell, D.D. 2001. Evaluation of cover crops and conservation tillage for organic sweetpotato Production in North Carolina. 16th Annual Southeastern Fruit and Vegetable Expo. 12 Dec 2001. Greensboro, NC.

Watson D.H. and T.W. Rufty. 2001. Impact of flooding on a Glomalean fungal population in an agricultural soil. 3rd International Conference on Mycorrhizas, "Diversity and Integration in Mycorrhizas". July, 2001. Adelaide, South Australia.

Wossink, A. and N. Kuminoff. 2005. Valuing the option to switch to organic farming: an application to U.S. corn and soybeans. Meeting of the European Association of Agricultural Economist (EAAE). 23-27 Aug 2005. Copenhagen, Denmark.

Wossink A., and N. Kuminoff. 2002. Economics of Transition to Organic Agriculture, Poster Presentation. Oral presentation at the National SARE Conference. 23-26 Oct 2002. Raleigh, NC.

Wossink, A. and N. Kuminoff. 2002. Economics of Transition to Organic Agriculture. Poster presentation at the 54th Annual Crop Protection School. 12 Dec 2002. Raleigh, NC.

Zhang W.J., J.S. Wu, C. Tu, and S. Hu. 2002. Microbial activities, biomass and N dynamics in alternative agroecosystems. Oral presentation at the National SARE Conference. 23-26 Oct 2002. Raleigh, NC.

Theses and Dissertations

Bell, M.C. 2002. A multidisciplinary approach to assessing changes in soil quality of diverse farming systems. NC State Univ. Raleigh, MS Thesis.

Collins, A.A. 2002. Characterization of bacterial communities in soil during the transition to organic agriculture. NC State Univ. Raleigh, MS Thesis.

Finney, D.M. 2005. Evaluation of sorghum sudangrass as a summer cover crop and marketable hay crop for organic, no-till production of fall cabbage. NC State Univ. Raleigh, MS Thesis.

Forehand, L.M. 2005. Evaluation of Commercial Beneficial Insect Habitat Seed Mixtures for Organic Insect Pest Management. NC State Univ. Raleigh, MS Thesis.

Greenwood, M.C. 2004. Interactions between soil invertebrates and entomopathogenic nematodes. NC State Univ. Raleigh, PhD Dissertation.

Jelinek, S.T. 2004. The Association of Weed Species Richness and Abundance with Field Margin Type in Crop Fields. NC State Univ. Raleigh, MS Thesis.

McClintock, N.C. 2004. Production and utilization of compost and vermicompost in sustainable farming systems. NC State Univ. Raleigh, MS Thesis.

Seem, Jessica. 2002. Critical Weed-Free Period for 'Beauregard' Sweetpotato (Ipomoea batatas) and Weed Seedbank Changes in Response to Transitioning from Conventional to Organic Farming Systems. NC State Univ. Raleigh, MS Thesis.

Stout, R.D. 2005. Distribution of Tomato spotted wilt virus (TSWV) in relation to wild weedy hosts and susceptible crops over a large agricultural landscape. NC State Univ. Raleigh, MS Thesis.

Treadwell, D.D. 2005. Management of a hairy vetch and rye cover crop influences wireworm (Conoderus spp.) density, weed density and biomass, sweetpotato yield, and cost of three organic sweetpotato production systems. NC State Univ. Raleigh, PhD Dissertation.

Treadwell, D.D. 2001. Intercropping a Living mulch of Buckwheat into sweetcorn for weed suppression. NC State Univ. Raleigh, MS Thesis.

Tungate, K.D. 2004. Environmental factors influencing weed interference in agricultural systems. NC State Univ. Raleigh, PhD Dissertation.

Bulletins

Finney, D.M. and N.G. Creamer. 2005. Weed Management for Organic Systems. Special topic Cultivation Practices for Organic Farms: D.W. Monks, K.M. Jennings, and W.E. Mitchem. Center for Environmental Farming Systems. Organic Production Training Series.

Linker, H.M., D.B. Orr, and M.E. Barbercheck. 2005. Insect Management. Center for Environmental Farming Systems. Organic Production Training Series.

Wossink, A. and N. Kuminoff. 2002. Organic Agriculture in North-Carolina, NC State Economics, Sept/Oct. Full text available on-line at: http://www.agcon.ncsu.edu/VIRTUAL_LIBRARY/ECONOMIST/septoct02.PDF

Books and book chapters

Morse, RD. and N.G. Creamer. 2005. Developing No Tillage Without Chemicals: The Best of Both Worlds? In: Organic Agriculture: A Global Perspective. CSIRO Publishing, Collingwood, Australia. (Expected release: October 2005).

Project Outcomes

Project outcomes:

Annual visits by students, agents and farmers have totaled between 500 and 1000. The number of people served since 1999 is more than5000. Twenty-nine graduate students have conducted research based at CEFS, 102 interns and 4 apprentices have also been trained at CEFS.
Ten articles have been published in scientific journals and three are currently in review. Thirteen abstracts have been presented at national and international conferences and symposiums, and 12 graduate student theses have been completed. CEFS is located in Wayne County, NC, continues to be a leader in sustainable and organic research and education in North Carolina, the southeastern U.S. and beyond.

Economic Analysis

All activities and inputs have been recorded for each field and subplot of each replicate of each system. These records form the basis for partial budget analyses and enterprise budget development. In compiling these data it has become clear that data collected from research station environments are not comparable to realistic farm conditions. Nevertheless, much of the economic work on the project has been based on generating annual crop budgets for each of the systems, laying the foundation for systems budgets that will eventually encompass multiple years and crops. To generate the budgets, we combined data from field trials, input prices from conventional NCSU crop budgets, and output prices from USDA. The budgets report returns over variable costs. After completing draft budgets we developed a framework to test the statistical significance of differences in returns between the systems. We also analyzed the impact of federal price support and risk management programs on crop budget returns. We solicited feedback on the draft budgets by providing our results to project participants at NCSU. In addition we summarized our cumulative work and preliminary results in an edition of The NC State Economist and as several documents posted on the OrganicAgInfo website. We are continuing to collect and analyze research data with the objective of using these data in models that will be useful in guiding economic decision-making.
Finally, we continued to follow current research and look for new data relevant to the economics of sustainable agriculture in the United States and internationally.

Farmer Adoption

Annual field days and focused training events regularly attract farmers interested in various aspects of the research. Of special interest has been research dedicated to transition strategies to organic production. Initial results of this research (which continues in 2006) indicates that first replacing synthetic fertilizer inputs first with organic fertilizer sources such as animal manure, compost, green manures is a promising strategy in the transition to organic farming. Farmers have also been interested in adopting several of the tillage techniques that are being used in research at FSRU, such as cultivation for weed control and smother-crop no-tillage methodology.

Recommendations:

Areas needing additional study

The Farming Systems Unit at CEFS is as a large-scale, interdisciplinary research and education center designed to continue for perpetuity. The experiment is currently in its seventh year and systems differences are just beginning to emerge. The data presented here document baseline conditions and changes that have emerged in the systems over the first seven years. In time this information will be used to evaluate the amount, direction, and speed of change in the systems and to assess the value of this set of indicators as related to soil quality, ecosystem health and crop productivity. We are currently in the development stages of an organic grain production system. In the future we would like to incorporate more measures of water quality.

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.