418 Properties of Soils in which Sticherus flabellatus Naturally Occurs

Sticherus flabellatus (R.Br.) St John, commonly known as Umbrella Fern, is a member of the Gleichenaceae family. Sticherus flabellatus is found on the N.S.W. coast and ranges, Qld, and eastern Victoria in Australia, as well as in New Zealand and New Caledonia. Fronds emerge from underground creeping rhizomes, forming large colonies in sheltered sites in moist gullies and creek banks in open forest. Propagation of the genus Sticherus has previously been relatively unsuccessful. The ferns are difficult to raise from spore and established specimens resent major disturbance to their roots, therefore making them hard to transplant. As a result of these difficulties the properties of the soil in which S. flabellatus grows naturally were investigated to determine the specific requirements for successful growth. Soil was collected from naturally occurring stands of S. flabellatus growing in a diverse range of sites within and on the periphery of the Sydney Basin. At each site a core of soil (12 cm diameter x 12 cm high) was taken at ≈0, 25, and 50 m along a line transect situated within a S. flabellatus stand, providing three replicates for each site. Physical and chemical properties were determined for each site. Particle size and consequently soil texture were determined using the hydrometer method. Electrical conductivity (EC) and pH readings were taken in a 1 soil: 5 water solution. pH readings were also taken in a 1 soil: 5 CaCl solution. Available P was analysed using the Bray (no. 2) method and organic carbon through colorimetric measurement after dichromate acid digestion. We found that S. flabellatus prefers growing in quite acidic soil with an average pH of 5.2 in a water solution and 4.0 in a CaCl solution. The EC readings were also significantly low with a mean reading of 37.0 μS•cm -1 . Organic carbon was measured at a mean of 2.4% and available P at 4.1 mg•kg -1 of soil. Using the International Soil Texture Triangle the soil in which S. flabellatus is found growing can be classified as sandy. The average sand content was 87.6%, clay 6.8% and silt 5.5%. These results show that S. flabellatus grows naturally in highly acidic, nutrient poor sandy soils that contain only minimal amounts of organic carbon and phosphorus. Therefore this needs to be taken in consideration when trying to successfully propagate the fern.