@article{CavaelDiehlLentzsch2020,
  author    = {Cavael, Ulrike and Diehl, Katharina and Lentzsch, Peter},
  title     = {Assessment of growth suppression in apple production with replant soils},
  series = {Ecological indicators : integrating monitoring, assessment and management},
  volume    = {109},
  journal   = {Ecological indicators : integrating monitoring, assessment and management},
  publisher = {Elsevier Science},
  address   = {Amsterdam},
  issn      = {1470-160X},
  doi       = {10.1016/j.ecolind.2019.105846},
  pages     = {9},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@article{CavaelDiehlLentzsch2020,
  author    = {Cavael, Ulrike and Diehl, Katharina and Lentzsch, Peter},
  title     = {Assessment of growth suppression in apple production with replant soils},
  series = {Ecological indicators : integrating monitoring, assessment and management},
  volume    = {109},
  journal   = {Ecological indicators : integrating monitoring, assessment and management},
  publisher = {Elsevier Science},
  address   = {Amsterdam},
  issn      = {1470-160X},
  doi       = {10.1016/j.ecolind.2019.105846},
  pages     = {9},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@misc{RudKaethnerGiesseretal.2018,
  author    = {Rud, R. and K{\"a}thner, Jana and Giesser, J. and Pasche, R. and Giebel, Antje and Selbeck, J{\"o}rn and Shenderey, C. and Fleury, D. and Zude-Sasse, Manuela and Alchanatis, Victor},
  title     = {Monitoring spatial variability in an apple orchard under different water regimes},
  series = {International Symposium on Sensing Plant Water Status - Methods and Applications in Horticultural Science},
  volume    = {1197},
  journal   = {International Symposium on Sensing Plant Water Status - Methods and Applications in Horticultural Science},
  publisher = {International Society for Horticultural Science},
  address   = {The Hague},
  isbn      = {978-94-62611-93-1},
  issn      = {0567-7572},
  doi       = {10.17660/ActaHortic.2018.1197.19},
  pages     = {139 -- 146},
  year      = {2018},
  abstract  = {Precision fruticulture addresses site or tree-adapted crop management. In the present study, soil and tree status, as well as fruit quality at harvest were analysed in a commercial apple (Malus × domestica 'Gala Brookfield'/Pajam1) orchard in a temperate climate. Trees were irrigated in addition to precipitation. Three irrigation levels (0, 50 and 100\%) were applied. Measurements included readings of apparent electrical conductivity of soil (ECa), stem water potential, canopy temperature obtained by infrared camera, and canopy volume estimated by LiDAR and RGB colour imaging. Laboratory analyses of 6 trees per treatment were done on fruit considering the pigment contents and quality parameters. Midday stem water potential (SWP), normalized crop water stress index (CWSI) calculated from thermal data, and fruit yield and quality at harvest were analysed. Spatial patterns of the variability of tree water status were estimated by CWSI imaging supported by SWP readings. CWSI ranged from 0.1 to 0.7 indicating high variability due to irrigation and precipitation. Canopy volume data were less variable. Soil ECa appeared homogeneous in the range of 0 to 4 mS m-1. Fruit harvested in a drought stress zone showed enhanced portion of pheophytin in the chlorophyll pool. Irrigation affected soluble solids content and, hence, the quality of fruit. Overall, results highlighted that spatial variation in orchards can be found even if marginal variability of soil properties can be assumed.},
  language  = {en}
}