Forskning ved Københavns Universitet - Københavns Universitet


Spatial and temporal oxygen distribution measured with oxygen microsensors in growing media with different levels of compaction

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Oxygen microsensors were used to determine oxygen profiles in situ from the top to the bottom layer of
the growing medium for potted plants of Rosa sp. ‘Dior’. The growing medium was peat- based and compacted
uniformly to 3 different bulk densities of 0.14, 0.18 and 0.23 g cm-3 (0, 20 and 40% compacted,
respectively). The water distribution in the pot was determined as water content (gcm-3) in the top,
middle and bottom layers of the peat. Oxygen content was also determined after a standard subirrigation
cycle and after excessive irrigation where the bottom of the pots were left waterlogged for 24 h.
Measurements were carried out at 5.5 weeks during the production phase and at 12 weeks at the end of
the production. The results showed that with increasing compaction and density, more water was transported
to the upper layers of the pot. After a standard irrigation cycle there was no effect of the level of
medium compaction on the oxygen distribution, whereas after excessive irrigation, the oxygen contents
at the bottom of the pots were strongly reduced and the level of compaction significantly affected oxygen
availability. The most compacted medium had the lowest oxygen content at 5.5 weeks, with anoxic
conditions in the bottom 30mm. Plant quality measured as fresh weight, dry weight, height and number
of shoots with flowers and buds was not affected by the different levels of compaction. The use of oxygen
microsensors provided a new insight into the spatial and temporal distribution of oxygen in growing
media and how this was affected by the physical characteristics of the growing media.
TidsskriftScientia Horticulturae
Udgave nummer1
Sider (fra-til)68-75
Antal sider8
StatusUdgivet - 2011

ID: 32439609