Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2005
Publication Date: June 1, 2005
Citation: Larkin, R.P. 2005. Effects of biological amendments on soil microbiology and soilborne potato diseases in different cropping systems. Phytopathology. v. 95. p. S-56. Technical Abstract: Various biological amendments, including commercial and research biocontrol agents, microbial inoculants, mycorrhizae, aerobic compost tea (ACT), and a biostimulant were evaluated for their effects on soil microbial community characteristics (SMCC) and soilborne diseases of potato in greenhouse and field trials in Maine. Most amendments successfully delivered organisms into the soil in the short term, significantly altering SMCC (as determined by FAME analysis) to various degrees 2 wk after amendment. Some amendments maintained significant effects on SMCC throughout the field season. Effects on soilborne diseases and yield were variable, with some microbial inoculants, a biostimulant, and foliar-applied ACT producing no significant effects on disease or tuber yield in 2-yr field trials, whereas arbuscular mycorrhizae, other microbial inoculants, and soil-applied ACT reduced disease and increased tuber yield in some trials. In field trials conducted within 3 different 2-yr crop rotations, amendments interacted with cropping system. Selected amendments significantly reduced Rhizoctonia disease and increased yield within specific barley rotations, but not in continuous potato. Both crop rotation and amendment treatments affected SMCC, but rotation effects were more extensive than amendment effects. These results indicate that certain rotations were better able to support the added beneficial organisms from amendments and enable more effective biological control, and also that favorable crop rotations may be more effective than amendments in manipulating or altering SMCC.