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

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

Summary

The Center for Environmental Farming Systems (CEFS) is an interdisciplinary research facility near Golsdboro, NC. Researchers from North Carolina State University and North Carolina A&T are examining agricultural managment 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. Research nested within the long term experiment continues to grow as faculty and graduate student involvment increases. Several research projects are ongoing while several concluded in fall of 2004.

In 2004 graduate students in Crop Science, Entomology, Crop Science/Entomolgy and Horticulture/Soil Science,completed or are continuing nested studies. A masters student in crop science completed her work examining weedy hosts and movement of Tomato Spotted Wilt Virus (TSWV). Results show that TSWV occurrence was equally likely to be found in the center versus the edge of crop fields, revealing that complete control of host species up to 60 m from a field may not aid in decreasing TSWV in a field. A graduate student in entomology completed 2 years of work examining the efficacy of three commercially available beneficial insect habitat (BIH) mixes. After two years of field studies, it was found that this BIH did not amplify parasitoid effectiveness in an organic tomato cropping system. A graduate student in crop science and entomolgy is continuing work comparing beneficial, (predator and parasitoid), and pest insect populations in conventional and organically managed systems. And a graduate student in horticulture and soil science completed work examing the use of sorghum sudangrass as a summer cover and hay crop for organic fall cabbage production.

Researchers in plant pathology are continuing their examination of soil bacterial populations and changes in soil carbon and nitrogen pools. A range of soil physical properties are still being collected in each of the five systems in the Farming Systems Unit at The Center for Environmental Farming Systems.

Objectives/Performance Targets

1. 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.

Accomplishments/Milestones

Robyn Stout(Under direction of Michael. G. Burton and H. Michael Linker) completed her masters in Crop Science. She examined the distribution of Tomato Spotted Wilt Virus (TSWV) in relation to wild weedy hosts and susceptible crops over a large agricultural landscape. TSWV is an important agronomic and horticultural pest in NC and other parts of the world. Many have speculated that management of weedy species that host the virus and its insect vector may aid in decreasing TSWV occurrence on a farm. In May of 2003 and 2004, weedy species were sampled around six fields conventionally managed fields in the Best Management Practice (BMP system). Plots were located at field edges and in field centers to detect differences between trivial movement of infected thrips and movement up to 60 m from bordering weedy hosts. TSWV occurrence was equally likely to be found in the center versus the edge plots, revealing that complete control of host species up to 60 m from a field may not aid in decreasing TSWV in a field. TSWV occurrence in and around the three replications that were spread across the farm revealed an effect of replication in 2003 when more virus was found in the southern-most replication. Ranunculus sardous (hairy buttercup) tested positive for TSWV most often compared to all other weed species tested and was also found in the highest density near the southern-most replication.

Lisa Jackson, a graduate student in crop science and entomology is examining beneficial, (predator and parasitoid), and pest insect populations in conventional and organically managed systems. Beneficial, (predator and parasitoid), and pest insect populations were compared in conventional, organic, and organic inter-planted with habitat cabbage plots. The effects of organic and conventional pesticides were compared by monitoring beneficial and pest insect populations in non-sprayed plots of each of the three above treatments. Preliminary results show aphid numbers were found to be highest in organic sprayed, and lowest in organic habitat non-sprayed. In addition she is also comparing beneficial, (predator and parasitoid), and pest insect populations in conventional and organic soybeans.

Lisa Forehand (Under the direction of H. Micheal Linker and David Orr) completed her masters in entomology. She evaluated beneficial insect habitat on an organic farm. Her first objective was to examine the purity, composition and germination of three commercially available beneficial insect habitat (BIH) mixes. All three companies had weed seeds present as well as advertised species absent. Composition and germination results varied considerably between the three companies. The second objective was to determine what insects (beneficial or otherwise) are attracted to select cut flower crops, cover crops, and commercial BIH seed blends. Over 42,000 insects were identified and categorized into feeding guilds. Two cut flowers/ herbs, Celosia and fennel had the lowest overall abundance and diversity index values for all feeding guilds, while one BIH had the highest values for beneficial predators and parasitoids and tied with a second company for highest values for herbivore crop pests. The third objective to construct and evaluate a simple beneficial insect habitat based on existing literature. The BIH with the greatest populations of beneficial insects from the second objective was transplanted around the perimeter of tomato plots to evaluate the ability of a readily available food source to increase the effectiveness of both egg and larvae parasitoids. After two years of field studies, it was found that this BIH did not amplify parasitoid effectiveness in an organic tomato cropping system.

Denise Finney finished her masters of Horticulture and Soil Science (Under direction of N.G. Creamer, M.G. Wagger, J.R. Schultheis). She examined the use of sorghum sudangrass as a summer cover and hay crop for organic fall cabbage production and found that removal of sorghum sudangrass biomass as hay did not impact total cover crop biomass or weed suppressive qualities of cover crop residues. No-till mulch of sorghum sudangrass generated by mowing less frequently offered broadleaf weed control in cabbage similar to that achieved with conventional tillage, though grass and sedge weed species were generally more abundant under no-till conditions. However, the presence of re-growing sorghum sudangrass contributed to lower cabbage head weight at one site and crop failure at the other under no-till management. Their findings suggest that the potential for growers to manage sorghum sudangrass as both a summer cover crop and hay crop does exist, however, this summer cover crop species may not be compatible with fall cabbage production

Charles W. Raczkowski, an NCA&T Principal Investigator continued to evaluate the impact of crop management systems and production practices on soil physical properties and monitor changes in soil quality. The results obtained were similar from those reported from 2002 and 2003. In general, no differences were found between systems for field capacity, hydraulic conductivity, plant-available water retention and soil microporosity. The bulk density results were somewhat consistent with the type of activity implemented. For example, bulk density was lowest in the organic system, a system that is tilled for the production of organic crops, and highest in the crop/animal system, a non-tilled environment compacted by the grazing activity of animals. No differences in bulk density were found between the no-till, trees and succesional 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.
Relationships among selected soil abiotic and biotic characteristics.

Dr. Cavell Brownie, the statistician on the project, is continually analyzing investigator data and looking for relationships among parameters. The following is a short summary of her work with Dr. Mary Barbercheck’s soil entomopathogen and arthropod data and Dr. Charles Razkowki soil physical parameters:

Cumulative counts of soil organisms were used to assess whether differences in abundance among the agriculture/eco-systems were related to changes observed in management-sensitive physical measurements such as bulk density and macroporosity or to other soil characteristics. The beneficial insect-parasitic nematode, Steinernema carpocapsa, was more abundant in systems in which bulk density increased, with the exception of the pasture system. Similarly, macroarthropods appeared to be more abundant in systems that resulted in increased bulk density and lower macroporosity, in particular the successional, pasture and woodlot systems. Presence of other arthropods tended to be associated with soil properties that differed with soil type and did not change with management. Thus Collembola spp were more abundant in soils which had low microporosity irrespective of the management system. Presence of the beneficial insect-parasitic nematode, Steinernema glaseri, was also associated with soils that were characterized by low microporosity and low soil moisture, and did not appear related to system effects.

Impacts and Contributions/Outcomes

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).

Lectures, Publications and Posters by CEFS faculty and graduates students:

Glover, Lauren H. 2004. Temporal Changes in Aggregate Stability and Biological Indexes in Five Diverse Agricultural Systems. MS Thesis, Department of Natural Resources, North Carolina A&T State University, Greensboro, NC.

Glover. L.H., and C.W.Raczkowski. 2003. Temporal Changes in Aggregate Stability in Diverse Agricultural Systems. Presented at the 2003 ASA, CSSA, and SSSA Annual Meeting. October 2003, Denver, Colorado.

Raczkowski C.W. 2002. Assesing Soil Quality Through Measurements of Soil Physical Properties. 2002. National SARE Conference, October 23 – 26, 2002. Raleigh, North Carolina.

Forehand, L.M. (D.O. Orr, H.M. Linker) 2004. Poster: Evaluation of Beneficial Insect Habitat on Organic Farms. 2004. California Conference on Biological Control, July 13-16, 2004. Berkeley, California.

Forehand, L.M. 2004. Verbal Presentation: Evaluation of Beneficial Insect Habitat on Organic Farms. 2004. Chatham County Extension Services, October 18, 2004. Pittsboro, North Carolina.

Forehand, L.M. (D.O. Orr, H.M. Linker) 2004. Poster Presentation: Evaluation of Beneficial Insect Habitat on Organic Farms. 2004. Chatham County Extension Services, October 18, 2004. Pittsboro, North Carolina.

Forehand, L.M. 2004. Verbal Presentation: Evaluation of Beneficial Insect Habitat on Organic Farms. 2004. Carolina Farm Stewardship Association , November 14, 2004. Asheville, North Carolina.

Forehand, L.M., (D.O. Orr, H.M. Linker) 2004. Poster Presentation: Evaluation of Beneficial Insect Habitat on Organic Farms. 2004. Carolina Farm Stewardship Association , November 14, 2004. Asheville, North Carolina.

Collaborators: