khrystyg

• Schultze, Sabrina; Kamenova, Stefaniya Kamenova; Lejzerowicz, Franck Laurent Patrick; Gryn, Kristina; Hjerde, Erik & Åberg, espen [Show all 7 contributors for this article] (2026). Apple replant syndrome: An example for complex system dynamics affecting soil health. Full text in Research Archive Show summary

  In apple orchards trees are replanted every 15-20 years to increase yields. This is usually done in the same soil due to space restrictions. However that often leads to problems in growth and yield of the new trees. This problem is called replant syndrome.

• Schultze, Sabrina; Kamenova, Stefaniya Kamenova; Lejzerowicz, Franck Laurent Patrick; Gryn, Kristina; Hjerde, Erik & Åberg, espen [Show all 7 contributors for this article] (2026). Exploring microbial diversity in healthy and sick orchard soils: Insights into replant syndrome mechanisms. Full text in Research Archive Show summary

  Replant syndrome (RS), or sick soil syndrome, is a microbially mediated soil-borne syndrome that causes significant economic losses in orchards worldwide. It occurs where the same or closely related species are replanted, leading to reduced growth and yield quality. The mechanisms behind this syndrome remain poorly understood, suggesting a complex microbial dysbiosis. Our study examines the microbiomes of “RS-symptomatic” (hereafter: symptomatic soils) and “healthy” orchard soils in Norway. We hypothesized that healthy soils would harbour higher microbial biodiversity. We found that the average shoot length of the lowest seven branches of a tree was the best proxy for replant syndrome in our dataset, but geographic region had a stronger effect on growth patterns than soil health status. We found no significant correlation between chemical and physical soil variables and RS. Our findings based on DNA sequencing showed a higher eukaryotic (18S) Shannon alpha diversity in soil than in roots at all locations, while prokaryotic diversity (16S) was significantly higher in roots than in soil in only one region (Telemark). Comparing healthy and symptomatic soil, we found a significantly higher Shannon alpha diversity in healthy soil for 16S soil samples only in one region (Telemark), while there were no significant differences for 18S, and no significant differences in beta diversity for either. Again, region had a stronger effect on alpha biodiversity in 16S than soil health status, and was also significant in 18S. Average shoot length of the lowest seven branches was negatively correlated with 16S (soil) Shannon alpha diversity in RS soil only, a trend that was repeated but not significant for 18S in roots. We conclude that broad ecological perspectives are necessary to understand RS and highlight the need for studies focusing specifically on functional traits and the soil food web.

• Schultze, Sabrina; Kamenova, Stefaniya Kamenova; Lejzerowicz, Franck Laurent Patrick; Gryn, Kristina; Hjerde, Erik & Åberg, espen [Show all 7 contributors for this article] (2026). Exploring Microbial Diversity in Healthy and Sick Orchard Soils: Insights into Replant Syndrome Mechanisms. Full text in Research Archive Show summary

  Replant syndrome (RS), or sick soil syndrome, is a microbially mediated soil-borne syndrome that causes significant economic losses in orchards worldwide. It occurs where the same or closely related species are replanted, leading to reduced growth and yield quality. The mechanisms behind this syndrome remain poorly understood, suggesting a complex microbial dysbiosis. Our study examines the microbiomes of “RS-symptomatic” (hereafter: symptomatic soils) and “healthy” orchard soils in Norway. We hypothesized that healthy soils would harbour higher microbial biodiversity. We found that the average shoot length of the lowest seven branches of a tree was the best proxy for replant syndrome in our dataset, but geographic region had a stronger effect on growth patterns than soil health status. We found no significant correlation between chemical and physical soil variables and RS. Our findings based on DNA sequencing showed a higher eukaryotic (18S) Shannon alpha diversity in soil than in roots at all locations, while prokaryotic diversity (16S) was significantly higher in roots than in soil in only one region (Telemark). Comparing healthy and symptomatic soil, we found a significantly higher Shannon alpha diversity in healthy soil for 16S soil samples only in one region (Telemark), while there were no significant differences for 18S, and no significant differences in beta diversity for either. Again, region had a stronger effect on alpha biodiversity in 16S than soil health status, and was also significant in 18S. Average shoot length of the lowest seven branches was negatively correlated with 16S (soil) Shannon alpha diversity in RS soil only, a trend that was repeated but not significant for 18S in roots. We conclude that broad ecological perspectives are necessary to understand RS and highlight the need for studies focusing specifically on functional traits and the soil food web.

• Edvardsen, Bente; Gryn, Khrystyna; Šupraha, Luka; Eikrem, Wenche & Saubrekka, Karoline (2023). Biodiversity and distribution of Arctic phytoplankton and ice algae. Universitetet i Oslo. Full text in Research Archive

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