TY  - JOUR
A1  - Cavael, Ulrike
A1  - Diehl, Katharina
A1  - Lentzsch, Peter
T1  - Assessment of growth suppression in apple production with replant soils
JF  - Ecological indicators : integrating monitoring, assessment and management
N2  - Apple replant disease (ARD) is a specific apple-related form of soil fertility loss due to unidentified causes and is also known as soil fatigue. The effect typically appears in monoculture production sites and leads to production decreases of up to 50%, even though the cultivation practice remains the same. However, an indication of replant disease is challenged by the lack of specification of the particular microbial group responsible for ARD. The objective of this study was to establish an algorithm for estimating growth suppression in orchards irrespective of the unknowns in the complex causal relationship by assessing plant-soil interaction in the orchard several years after planting. Based on a comparison between no-replant and replant soils, the Alternaria group (Ag) was identified as a soil-fungal population responding to replant with abundance. The trunk cross-sectional area (CSA) was found to be a practical and robust parameter representing below-ground and above-ground tree performance. Suppression of tree vigour was therefore calculated by dividing the two inversely related parameters, Q = ln(Ag)/CSA, as a function of soil-fungal proportions and plant responses at the single-tree level. On this basis, five clusters of tree vigour suppression (Q) were defined: (1) no tree vigour suppression/vital (0%), (2) escalating (- 38%), (3) strong (- 53%), (4) very strong (- 62%), and (5) critical (- 74%). By calculating Q at the level of the single tree, trees were clustered according to tree vigour suppression. The weighted frequency of clusters in the field allowed replant impact to be quantified at field level. Applied to a case study on sandy brown, dry diluvial soils in Brandenburg, Germany, the calculated tree vigour suppression was 46% compared to the potential tree vigour on no-replant soil in the same field. It is highly likely that the calculated growth suppression corresponds to ARD-impact This result is relevant for identifying functional changes in soil and for monitoring the economic effects of soil fatigue in apple orchards, particularly where long-period crop rotation or plot exchange are improbable.
KW  - orchard management
KW  - trunk cross-sectional area
KW  - alternaria group
KW  - apple
KW  - production
KW  - soil fatigue
KW  - apple replant disease
Y1  - 2019
U6  - https://doi.org/10.1016/j.ecolind.2019.105846
SN  - 1470-160X
SN  - 1872-7034
VL  - 109
PB  - Elsevier Science
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Cavael, Ulrike
A1  - Diehl, Katharina
A1  - Lentzsch, Peter
T1  - Assessment of growth suppression in apple production with replant soils
JF  - Ecological indicators : integrating monitoring, assessment and management
N2  - Apple replant disease (ARD) is a specific apple-related form of soil fertility loss due to unidentified causes and is also known as soil fatigue. The effect typically appears in monoculture production sites and leads to production decreases of up to 50%, even though the cultivation practice remains the same. However, an indication of replant disease is challenged by the lack of specification of the particular microbial group responsible for ARD. The objective of this study was to establish an algorithm for estimating growth suppression in orchards irrespective of the unknowns in the complex causal relationship by assessing plant-soil interaction in the orchard several years after planting. Based on a comparison between no-replant and replant soils, the Alternaria group (Ag) was identified as a soil-fungal population responding to replant with abundance. The trunk cross-sectional area (CSA) was found to be a practical and robust parameter representing below-ground and above-ground tree performance. Suppression of tree vigour was therefore calculated by dividing the two inversely related parameters, Q = ln(Ag)/CSA, as a function of soil-fungal proportions and plant responses at the single-tree level. On this basis, five clusters of tree vigour suppression (Q) were defined: (1) no tree vigour suppression/vital (0%), (2) escalating (- 38%), (3) strong (- 53%), (4) very strong (- 62%), and (5) critical (- 74%). By calculating Q at the level of the single tree, trees were clustered according to tree vigour suppression. The weighted frequency of clusters in the field allowed replant impact to be quantified at field level. Applied to a case study on sandy brown, dry diluvial soils in Brandenburg, Germany, the calculated tree vigour suppression was 46% compared to the potential tree vigour on no-replant soil in the same field. It is highly likely that the calculated growth suppression corresponds to ARD-impact This result is relevant for identifying functional changes in soil and for monitoring the economic effects of soil fatigue in apple orchards, particularly where long-period crop rotation or plot exchange are improbable.
KW  - orchard management
KW  - trunk cross-sectional area
KW  - alternaria group
KW  - apple
KW  - production
KW  - soil fatigue
KW  - apple replant disease
Y1  - 2020
U6  - https://doi.org/10.1016/j.ecolind.2019.105846
SN  - 1470-160X
SN  - 1872-7034
VL  - 109
PB  - Elsevier Science
CY  - Amsterdam
ER  -