Water repellent soils as they occur on UK golf greens

Water repellent soils have been identified as a major problem in the management of golf greens in the UK for over 60 years. The cause of this problem has provoked much speculation, but prior to this work, no research into the possible cause of water repellent soils in the UK had been completed. One of the commonly believed links with water repellent soils on UK golf greens was the activity of basidiomycete fungi. This was proposed as a possible causal factor because the symptoms expressed on the turf above affected soils, were similar in many instances to those symptoms expressed by the activity of superficial fairy rings. Since it was impractical to study superficial fairy rings, it was decided to observe other basidiomycete fairy rings (Type 1 fairy rings) to see if any water-repellence could be identified as being associated with them. Three of these rings, caused by the fungus Marasmius oreades (Bolt ex. Fr) Fr., were studied on each of the two different sites. Soil samples were removed at intervals from the centre of the rings, across the obvious symptoms of the rings (i.e. the zone of dead grass bordered on both sides by a zone of stimulated grass growth) and beyond, into the uncolonised soil. These samples were taken to the laboratory, allowed to air dry and were then tested to determine relative levels of water repellence. It was found that on the 'outside' of the fairy rings where the fungus had not yet colonised, the soils were less water repellent than they were in the other zones of the rings (i.e. the dead zone and the inner zone). In the region of the dead zone of these fairy rings, the soil was very water repellent. This may have been expected because the fungus was present in this area in large quantities and the fungus itself repels water. However, of particular interest, were the results from the inner part of the ring where the fungus had been present in the past, but where it no longer colonised the soil. In these soil samples, the rootzone soil was still very water repellent. It was concluded from the study that it was possible for basidiomycete-type fungi to effect water repellence on soils through which they have passed. Thus, this may be at least a contributory factor to the development of severely water repellent soils on UK golf greens.