TY - JOUR

T1 - Non-target effects of the microbial control agents Pseudomonas fluorescens DR54 and Clonostachys rosea IK726 in soils cropped with barley followed by sugar beet

T2 - a greenhouse assessment

AU - Johansen, Anders

AU - Knudsen, Inge M.B.

AU - Binnerup, Svend J.

AU - Winding, Anne

AU - Johansen, Jens E.

AU - Jensen, Linda E.

AU - Andersen, Karen Stevnbak

AU - Svenning, Mette M.

AU - Bonde, Torben A.

N1 - Keywords: Risk assessment; Microbial control agent; Soil microbiota; Non-target effect

PY - 2005

Y1 - 2005

N2 - Non-target effects of a bacterial (Pseudomonas fluorescens DR54) and a fungal (Clonostachys rosea IK726) microbial control agent (MCA), on the indigenous microbiota in bulk soil and rhizosphere of barley, and subsequent a sugar beet crop, were studied in a greenhouse experiment. MCAs were introduced by seed and soil inoculation. Bulk and rhizosphere soils were sampled regularly during the growth of barley and sugar beet. The soils were assayed for the fate of MCAs and various features of the indigenous soil microbiota. At the end of the experiment (193 d), DR54 and IK726 had declined by a factor of 106 and 20, respectively, and DR54 showed a short-lasting growth increase in the sugar beet rhizosphere. In general, the non-target effects were small and transient. IK726 seemed to have general stimulating effects on soil enzyme activity and the soil microbiota, and resulted in a significant increase in plant dry weight. The plant growth-promoting effect of DR54 was less pronounced and the DR54 displaced indigenous pseudomonads. DR54 stimulated growth of protozoans with a tolerance for the anti-fungal compound viscosinamide produced by DR54. Treatment with the fungicide Fungazil had no effects on plant growth or soil microorganisms. Phospholipid fatty acid (PLFA) analysis detected the perturbations of the soil microbial community structure in the MCA treatments as well as the return to non- perturbed conditions reflecting the decline of inoculant populations. The PLFA technique appears to be suitable for in situ monitoring of MCA non-target effects on the soil microbiota, but should be combined with assays for MCA survival and soil enzyme activity.

AB - Non-target effects of a bacterial (Pseudomonas fluorescens DR54) and a fungal (Clonostachys rosea IK726) microbial control agent (MCA), on the indigenous microbiota in bulk soil and rhizosphere of barley, and subsequent a sugar beet crop, were studied in a greenhouse experiment. MCAs were introduced by seed and soil inoculation. Bulk and rhizosphere soils were sampled regularly during the growth of barley and sugar beet. The soils were assayed for the fate of MCAs and various features of the indigenous soil microbiota. At the end of the experiment (193 d), DR54 and IK726 had declined by a factor of 106 and 20, respectively, and DR54 showed a short-lasting growth increase in the sugar beet rhizosphere. In general, the non-target effects were small and transient. IK726 seemed to have general stimulating effects on soil enzyme activity and the soil microbiota, and resulted in a significant increase in plant dry weight. The plant growth-promoting effect of DR54 was less pronounced and the DR54 displaced indigenous pseudomonads. DR54 stimulated growth of protozoans with a tolerance for the anti-fungal compound viscosinamide produced by DR54. Treatment with the fungicide Fungazil had no effects on plant growth or soil microorganisms. Phospholipid fatty acid (PLFA) analysis detected the perturbations of the soil microbial community structure in the MCA treatments as well as the return to non- perturbed conditions reflecting the decline of inoculant populations. The PLFA technique appears to be suitable for in situ monitoring of MCA non-target effects on the soil microbiota, but should be combined with assays for MCA survival and soil enzyme activity.

KW - Former LIFE faculty

KW - Risk assessment; Microbial control agent; Soil microbiota; Non-target effect

U2 - 10.1016/j.soilbio.2005.04.004

DO - 10.1016/j.soilbio.2005.04.004

M3 - Journal article

VL - 37

SP - 2225

EP - 2239

JO - Soil Biology & Biochemistry

JF - Soil Biology & Biochemistry

SN - 0038-0717

IS - 12

ER -