THE INFLUENCE OF IRRIGATION ON GAS COMPOSITION IN THE RHIZOSPHERE AND GROWTH OF THREE HORTICULTURAL PLANTS, CULTIVATED IN DIFFERENT SUBSTRATES

The objective of this study was to investigate how irrigation affected the gas (CO₂ and O₂) composition in air space of different substrates and how the changes in the substrate air composition influenced some plant physiological and growth parameters.
In the first investigation, Ficus benjamini L. was cultivated in two different peat substrates (A-710 and E 910) in a whole plant cuvette.
The substrates differed in the clay content, which was 0% or 20% in A 710 and E 910, respectively.
Measurements of CO₂– and O₂-contents of the substrate air space were carried out continuously.
Plants height, the number of sprouts and new leaves were determined weekly and the leaf fresh weight was measured at the end of experiment.
In the second experiment, paprika (Capsicum annuum L.) was cultivated in perlite or in a peat substrate with a medium particle size in a whole plant cuvette.
CO₂– and O₂ concentration in substrates were continuously recorded, with regard to water application.
In the third experiment, continuous oxygen measurements were recorded in a wood fiber or rockwool substrate, where cucumber plants (Cucumis sativus L.) were grown.
In the first experiment, only slight changes in the gas composition were found in peat substrates after moderate irrigation; more evident changes occurred for daily O₂ and CO₂ concentrations, most likely due to influence of temperature on root respiration and microbial activity.
No differences were found between peat substrates with or without clay.
In experiment with paprika, continuous decrease of the O₂ content was observed in a perlite and in peat substrate after an irrigation of 5 L water per 50 L of substrate, while the CO₂ content was increased only transiently; normal O₂ levels were achieved after several days.
Another phenomenon was observed in the experiment with cucumber grown in wood fiber: soon after irrigation, O₂ content rose momentarily the level recorded just prior irrigation.

International Symposium on High Technology for Greenhouse System Management: Greensys2007

T. Rocksch, N. Gruda, U. Schmidt

CO₂, Capsicum annuum L., Cucumis sativus L., Ficus benjamini L., O₂, peat, substrate

https://doi.org/10.17660/ActaHortic.2008.801.138