PARENT SESSION
Poster Session 24: Agro-Ecology
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Indicators of soil quality in organic and conventional potato fields in the Maritimes.
Nesbitt, Johanna*,1, Adl, Sina*,1, 1 Dalhousie University, Halifax, Nova Scotia, Canada
ABSTRACT- Although conventional agriculture has increased yield in the short term, the intensification of agricultural inorganic inputs, including fertilizers and pesticides, may be detrimental to the sustainability of agriculture and the environment. As an alternative, certified organic agriculture emphasizes the importance of soil biological activity as a means of growing higher yielding, pest free products. Soil quality, defined by Doran and Parkin in 1994, is a concept that is used to evaluate soils fitness for function in managed systems. There is a need for a soil quality index that would use a combination of biological, physical, and chemical indicators to qualitatively evaluate agroecosystems under differing management systems. Using eleven standard indicators of soil quality, conventionally and organically managed potato fields in New Brunswick, Prince Edward Island, and Nova Scotia were compared over the 2004 growing season. Although there are few studies that can serve as soil quality indicator baselines in the Maritimes, benchmarks were gathered from studies of similar climates and management practices. Mites (Acari), collembola, nematodes, testate amoebae, microbial biomass, cellulase assays, and ATP extraction served as bioindicators, while bulk density, soil moisture content, light fraction, and pH served as the physical and chemical indicators. Preliminary analysis has shown no statistically significant difference between conventionally and organically managed potato fields. This suggests that the effects of chemicals on the state of nutrient cycling through decomposition may be less destructive than practices shared by both management regimes, such as the physical disturbance of tillage. Further studies using bioindicators of soil quality are needed to increase the baseline values used in soil quality indexing in the Maritimes, and for further investigation of tillage and no-till practices.
Key words: soil quality, bioindicator, agroecosystem, soil ecology