ARS | Publication request: A systems approach for enhancing soil quality and plant health under organic and conventional conditions: Effects on soilborne diseases and tuber yield

Submitted to: Northeast Potato Technology Forum
Publication Type: Proceedings
Publication Acceptance Date: March 2, 2009
Publication Date: March 6, 2009
Citation: Larkin, R.P., Tavantzis, S., Erich, M., Bernard, E., Gross, S., Alyokhin, A. 2009. A systems approach for enhancing soil quality and plant health under organic and conventional conditions: Effects on soilborne diseases and tuber yield. Northeast Potato Technology Forum Proceedings. p. 14.

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 soilborne diseases and potato yield in field trials in northern Maine under both conventional and organic potato production practices. At the conventional site in 2007, compost amendment and biocontrol treatments (Tvir and HvRs) reduced incidence and severity of black scurf by 10-31%, and compost amendment also increased tuber yields by 13-23%. The combined effect of compost and biocontrol amendments reduced black scurf by 30-48% and increased yield. However, in 2008, compost amendment resulted in increased scurf and common scab severity (by 20-60%). At the organic site, compost had no effect on scurf or scab in 2007, but resulted in increased black scurf in 2008 (20%). In 2007, biocontrol treatments (Tvir and Bsub) reduced incidence and severity of black scurf by 10-48%, scab by 5-20%, and the total of all diseases by 15-30%, but did not consistently reduce disease in 2008. Brassica rotation reduced all soilborne diseases (black scurf, common scab, and silver scurf) by 20-57% at both sites. In 2007, compost amendment significantly increased total and marketable tuber yields (by 9-30%) at both sites, whereas biocontrol amendment did not affect yield. In 2008, compost amendment increased yields at the conventional site (6-15%), but not at the organic site. These studies indicate that compost and biocontrol amendments, and disease-suppressive rotations, can have significant positive effects on soil quality, disease reduction, and yield, and should play an important role in sustainable soil and disease management programs.