ARS | Publication request: A systems approach for enhancing soil quality and plant health under organic and conventional conditions: Effects on soil properties and fertility

Submitted to: Northeast Potato Technology Forum
Publication Type: Proceedings
Publication Acceptance Date: March 2, 2009
Publication Date: March 6, 2009
Citation: Erich, M., Tavantzis, S., Larkin, R.P., Alyokhin, A., Gross, S., Bernard, E. 2009. A systems approach for enhancing soil quality and plant health under organic and conventional conditions: Effects on soil properties and fertility. Northeast Potato Technology Forum Proceedings. p. 12.

Technical Abstract: Three factors associated with soil regeneration and sustainable production (compost amendments, biocontrol amendments, and Brassica green manures) were evaluated, both individually and in combination, for their effects on soil properties at a conventionally-managed farm (CF) and an organically-managed farm (OF) in Northern Maine in 2007 and 2008. Soil quality was very different between the two sites, with the level of soil organic matter about twice as high at the organic site. In 2007, OF had higher levels of water stable aggregates (WSA) at each of the three sampling times than CF. Compost amendment did not affect aggregation at either site. Biocontrol amendment generally did not affect soil properties at either site. Brassica rotation may have had some effect on soil properties (pH, OM, P, and C) at OF, but not at CF. Although soil moisture was always significantly higher at OF than CF, compost amendment did not affect soil moisture at either site in either year. At the CF site, soil moisture was higher in 2008 than in 2007 at most sampling times. In 2007, soluble inorganic N levels were higher at CF than OF in late June due to the use of inorganic N fertilizer at CF. At all other sampling dates, N levels were similar at the two sites and unaffected by compost use. Nitrate levels were lower at both sites in 2008 than 2007, perhaps due to higher rainfall close to sampling dates in 2008. In 2008 nitrate levels were consistently higher in CF soils than OF soils. These results indicate much higher soil quality at the organically-managed site compared to the conventional site, and that compost and biocontrol amendments had little direct effect on soil properties. These results have implications on fertility, yield, and the management of soilborne diseases.