The Impact of Agricultural Systems on Soil Quality and Sustainability

The Impact of Agricultural Systems on Soil Quality and Sustainability

Summary

A comparison of several biotic and abiotic characteristics of soil among five diverse systems indicates that system affects abundance, diversity and community structure of bacteria, pest and beneficial nematodes, insect pathogens, and microarthropods; and carbon dioxide evolved, bulk density, porosity, hydraulic conductivity and aggregate stability. To date, most differences appear to be related to soil disturbance by tillage, although higher plant diversity may be related to greater abundance of nematodes in the successional system. The pattern of carbon evolution suggests greater microbial activity where surface crop residues are maintained or where animal manure consitutes part of the fertility regime.

Objectives/Performance Targets

Our objectives are to:
1. Develop indicators of soil quality for assessing ecological shifts related to sustainability, e.g., biotic and abiotic factors associated with low pest populations, increased crop health and/or tolerance to pest damage and crop quality and yield.
2. Determine the impact of agricultural system on selected soil organisms and soil chemical and physical indicators.

Accomplishments/Milestones

The systems studied include: successional (old field), forestry/woodlot, integrated crop/animal with six rotations of different lengths, organic production, and conventional best management system with no till and conventional till. Crops in 2001 included annual and perennial pasture grasses, soybeans, cotton and black walnut. We collected and processed soil samples from geo-referenced points within each system in March, May, July and September, 2001. These data are being managed in a GIS database and will be analyzed to determine the spatial and temporal relationship among the measured factors, and their relationship to crop productivity and quality. We will sample the systems again in 2002, analyze data to determine possible indicators of soil quality, and test these indicators based on a reduced number of parameters on selected farms in North Carolina in 2003.

Impacts and Contributions/Outcomes

Data collection and analysis are ongoing. Several presentations on the progress and reusults of the project thus far have been made at meetings, grower’s schools, and field days at the Center for Environmental Farming Systems. A list of some of these follow:

Desarrollo y Implementacion de un Estudio de Sistemas Agricolas al Gran Escala y Larga Duracion. I Simposio Internacional sobre Ganaderia Agroecologica, La Habana, Cuba, 6-8 December, 2001. (Mueller, Barbercheck, Bell, Brownie, Creamer, Hu, King, Linker, Louws, Marra, Raczkowski, Susko, Wagger)

Investigaciones Sobre la Ecologia del Suelo en el Centro de Sistemas Agricolas Ambientales. IV Taller Internacional sobre Recursos Fitogeneticos, Sancti Spiritus, Cuba, 3-4 December, 2001. (Barbercheck, Bell, Brownie, Louws, Koenning, Raczkowski, Wagger)

Organic Agriculture Research at the Center for Environmental Farming Systems. Carolina Farm Stewardship Association 16th Annual Sustainable Agriculture Conference, Rock Hill, SC, Nov. 2-4, 2001. (Barbercheck, Bell, Brownie, Creamer, Hu, Linker, Louws, Mueller, Raczkowski, Wagger)

Sustainable Agriculture Research at the Center for Environmental Farming Systems. Carolina Farm Stewardship Association 16th Annual Sustainable Agriculture Conference, Rock Hill, SC, Nov. 2-4, 2001. (Barbercheck, Bell, Brownie, Creamer, Hu, Linker, Louws, Mueller, Raczkowski, Wagger)

Qualitative and quantitative indicators of soil quality. Carolina Farm Stewardship Association 16th Annual Sustainable Agriculture Conference, Rock Hill, SC, Nov. 2-4, 2001. (Bell, M.C., M.E. Barbercheck, F.J. Louws, and M.G. Wagger.)

Conservation of Insect Pathogens in the Soil. IOBC-ESCOP meeting, The Practice of Biological Control: Importation and management of natural enemies and agents. Aug. 2-5, 2001, Bozeman, MT (Barbercheck)

Soil Ecology at the Center for Environmental Farming Systems. Soil Ecology Society Conference, May 20-23, 2001, Calloway Gardens, GA. (Barbercheck, Bell, Brownie, Creamer, Hu, Linker, Louws, Mueller, Raczkowski, Wagger)

The Ground Crew – Soil Arthropods and Beneficial Organisms. Invited. SC Organic Grower’s School. Columbia, SC, 22 September 2001. (Barbercheck, Collins, Louws)

Transition strategies to organic production systems: economic and environmental indicators. Center for Environmental Farming Systems Field Day, July 9, 2001 (Barbercheck, Creamer)

Physical and chemical indicators of soil quality in diverse agricultural systems. Center for Environmental Farming Systems Field Day, July 9, 2001 (Bell, Raczkowski, Wagger)

Collaborators: