Submitted to: World Congress of Soil Science
Publication Type: Abstract Only
Publication Acceptance Date: 6/15/2006
Publication Date: 7/9/2006
Citation: Larkin, R.P. 2006. Biological amendments and crop rotations for managing soil microbial communities and soilborne diseases of potato. World Congress of Soil Science. CD-ROM
Technical Abstract: Various biological amendments, including commercial biocontrol agents, microbial inoculants, mycorrhizae, and an aerobic compost tea (CT), were evaluated, alone and in conjunction with different crop rotations, for their efficacy in introducing beneficial microorganisms, affecting soil microbial community characteristics (SMCC), and reducing soilborne diseases of potato in greenhouse and field trials in Maine. Most amendments successfully delivered microorganisms into the soil, significantly altering SMCC (as determined by FAME analysis) to various degrees from 2 to 24 weeks, and some amendments maintained significant effects throughout the field season. Effects on soilborne diseases and tuber yield were variable, with some microbial inoculants and a biostimulant producing no significant effects, whereas arbuscular mycorrhizae, other microbial inoculants, and soil-applied CT reduced soilborne diseases (black scurf and common scab) and increased yield in some trials. When used in different crop rotations, biological amendments reduced disease and improved yield in some rotations, but not others. Amendments were effective within specific barley rotations, but not in continuous potato. Both crop rotation and amendment treatments significantly affected SMCC, but rotation effects were more extensive. 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. Establishment and persistence of amendment effects may depend on many factors, but an effective and supportive crop rotation is apparently important.