Effects of carbon dioxide concentrations on three grass species grown in mixture in two soil types at different ozone concentrations or temperatures

Abstract

A seed mixture of Phleum pratense L., Lolium perenne L. and Festuca pratensis Huds. was grown in spaghnum peat or sandy soil in six growth chambers placed in a greenhouse compartment. Two different experiments were performed. Increasing the CO₂ concentration from 375 to 740 μmol mol⁻¹ increased the total dry weight of the grass mixture by about 30%, while an increase in the O₃ concentration from < 10 to 50 nmol mol⁻¹ decreased the dry weight by 18% as a mean in both experiments. The relative dry weights of the three species were not significantly affected by elevated CO₂ concentrations at low O₃, while Lolium increased its relative dry weight at high O₃concentrations at low CO₂ on the expenditure of Phleum dry weight. CO₂ enrichment counteracted some of this O₃ effect. No significant interaction between CO₂ concentration and temperature (14 and 19°C mean temperature) was found with respect to the dry weights of the three species. The soil type had generally no influence on the effect of CO₂ and O₃. However, plant growth was significantly slower in sandy soil than in peat.

Key words:

• C0₂ concentration
• grass mixture
• O₃ concentration
• soil type
• temperature

Notes

Address for correspondence.