Measurement of seasonal variations in the oxygen uptake of various litter layers of an oak forest

Summary The oxygen uptake of decomposing oak leaves in three litter layers was determined with a Gilson respirometer at least once a month. Samples were taken from Meerdink forest over a period of two years. The determinations were made at the same temperatures as those prevailing in the soil in the field at the moment of sampling. Due probably to the supply of fresh litter, the respiration in the L layer is the same in the winter as in the summer, when high temperatures have a stimulatory effect on respiration. In the F and H layers the composition of the material is much more constant, and there is a distinct effect of soil temperature on respiration corresponding with a Q10 of 2. It must be taken into account here, however, that in the H layer root respiration accounts on average for 40 per cent of the total respiration. The moisture content of the decomposing material seems to have a marked effect only in the L layer during prolonged periods of drought. No relationship was found between the level of respiration and the degree of mycelial growth on nylon gauze, although the main contribution to respiration was made by fungi. The respiration of the various litter layers represents an energy consumption which is in good agreement with the annual decomposition of organic matter in the soil. R.I.N.-communication nr. 102. R.I.N.-communication nr. 102.