Browsing by Author "Robinson-Boyer, Louisa"
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Item Open Access Effect on microbial communities in apple orchard soil when exposed short-term to climate change abiotic factors and different orchard management practices(Oxford University Press, 2023-01-11) Cook, Chris; Magan, Naresh; Robinson-Boyer, Louisa; Xu, XiangmingAim We assessed the effect of exposing apple orchard soil to different temperatures and CO2 levels on the resident microbiome of soils from a conventionally managed and an organically managed apple orchard. The key difference between these two orchards was that synthetic fertilizers and pesticides are routinely used in the former one. Methods and results To investigate the effect of CO2 and temperature soil samples from each site at two depths were exposed to elevated temperature (29°C) at either 5,000 or 10,000 ppm for 5 weeks or control conditions (25°C + 400 ppm). Both bacterial and fungal communities were profiled with amplicon-sequencing. The differences between the two orchards were the most significant factor affecting bacterial and fungal communities contributing to 53.7% and 14.0% of variance in Bray-Curtis β diversity respectively. Elevated CO2 concentration and increased temperature affected organic orchard microbial diversity more than the conventionally managed orchard. A number of candidate beneficial and pathogenic microorganisms had differential abundance when temperature and CO2 were elevated, but their effect on the plant is unclear. Conclusions This study has highlighted that microbial communities in bulk soils are most significantly influenced by crop management practice compared to the climate conditions used in the study. The studied climate conditions had a more limited effect on microbial communitiy diversity in conventionally managed soil samples than in organically managed soils.Item Open Access Understanding the resilience of soil beneficials to combat apple replant disease (ARD).(2022-09) Cook, Christopher; Magan, Naresh; Robinson-Boyer, Louisa; Xu, Xiangming; Medina-Vayá, ÁngelApple Replant Disease (ARD), caused by an accumulation of soil-borne fungal and oomycete pathogens in the soil, is an economically important disease of apples. Current management relies on the use of broad-spectrum chemical fumigation. Banning of chemical products has seen increased research into biological management strategies for ARD. This study aimed to test the efficacy of a number of commercially available biological soil amendments to improve the establishment of young apple trees in an attempt to minimise the detrimental effects of ARD. It also looked at changes in planting position and rootstock selection at planting to manage ARD and how climate change abiotic factors affect bulk apple soil microbiome communities. The efficacy of single species amendments was variety specific in the field. There was a increased rate of tree girth expansion in Gala trees amended pre-planting with Pseudomonas fluorescens but the same effect was not observed with Braeburn trees. The single species amendments did not increase the establishment of young apple trees either individually or in a consortium of amendments in semi-field conditions. In both field and semi-field conditions pre-plant amendment significantly altered the abundance of individual operational taxonomic units (OTUs) associated with both beneficial and pathogenic taxa of plants. The planting position in the inter-row alleyways and the genetic relationship of the new rootstock to the previously planted rootstock on the site were both identified to minimise ARD severity. In addition, a significant effect of CO₂ concentration and temperature increase on bulk soil microbiome communities was observed but this was not as significant as site management (organic vs conventional) effect. This research will aid with the development of management strategies for ARD by integrating single species biological amendments and cultural approaches with other management practices.