The Impact of Agricultural Systems on Soil Quality and Sustainability

Project Overview

Project Type: Research and Education
Funds awarded in 2000: $191,263.00
Projected End Date: 12/31/2002
Region: Southern
State: North Carolina
Principal Investigator:
Mary Barbercheck
North Carolina State University

Annual Reports


  • Agronomic: corn, cotton, peanuts, rye, soybeans, wheat
  • Vegetables: sweet potatoes, broccoli, tomatoes
  • Animals: bovine
  • Animal Products: dairy


  • Animal Production: pasture fertility, grazing - rotational
  • Crop Production: conservation tillage
  • Education and Training: demonstration, display, extension, on-farm/ranch research
  • Farm Business Management: budgets/cost and returns
  • Natural Resources/Environment: biodiversity, indicators
  • Pest Management: biological control, chemical control, competition, cultural control, field monitoring/scouting, integrated pest management, mulches - killed
  • Production Systems: agroecosystems, holistic management, transitioning to organic
  • Soil Management: green manures, organic matter, soil analysis, nutrient mineralization, soil quality/health


    An interdisciplinary research project compared  soil attributes in agricultural systems: a best management practice (BMP) system; an integrated crop/animal system; an organic production system; a forestry/woodlot system; and a successional ecosystem.  Soil nematode population density maxima for most trophic groups were in July of each year. Three species of beneficial insect-parasitic nematodes, Steinernema carpocapsae,  S. glaseri and Heterorhabditis bacteriophora, and two insect-pathogenic fungi, Beauveria and Metarhizium, were isolated from the site. Cumulative abundance of soil microarthropods was greater in the organic, successional and BMP no-till treatments than in the Woodlot, BMP conventional till and pasture plots.    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 greater in the conventional system.  Carbon and N availability were consistently and significantly lower in grassland, forest and successional systems than in the two agricultural systems, whereas C availability was higher in the grassland and organic soils. High C availability and low N in grasslands significantly affected soil microbes and led to higher microbial biomass C:N ratios and lower N mineralization, suggesting a shift of microbial community composition.

    Project objectives:

    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 yield/quality)
    2 ) determine the impact of agricultural system on selected soil organisms and soil chemical/physical indicators

    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.