Due to several record breaking dry summers within the UK over the last few years, summer moisture management has certainly been in the forefront for many greenkeepers. As opposites generally attract, these are often followed by extremely wet winters.
My next article is discussing winter moisture management programme, in particular the consequences of a prolonged wet soil profile and some of the common prevention methods available to greenkeepers and groundsmen.
Issues With Excessive Mositure Within A Rootzone
Microdochium Nivale (Fusarium Patch Disease) becomes problematic when turf experiences lengthy periods of cool, wet weather typical of autumn to winter periods. When there is cool, wet weather the mycelium grows from thatch or soil and infects leaves. Managing thatch is another important way of controlling this disease as there is a direct correlation between high thatch levels and the amount of moisture that is retained within the thatch layer. A deep moist thatch layer creates a favourable environment to the disease to thrive.
Thatch layers act as a “natural sponge” absorbing and retaining moisture near the surface. This surface water will help aid in the spread of this disease as it will allow for the spores to contact nearby healthy plants. The disease becomes very severe if allowed to spread from the leaf blades to the crown of the plant. Despite the fact that cultural controls cannot completely control Fusarium Patch, good moisture management can reduce disease pressure, this can have a noticeable impact and will help to reduce the amount of chemical control that is required.
Surface Firmness for Playability
As well as discussing the benefits of limiting excessive moisture for a integrated disease management approach. Limiting periods of excess moisture can create a firmer playing surface to aid the playabilty of the green or football pitch. In golf pitchmarks and players footprints around the flagpin can prove problematic and deteriorate the trueness of the playing surface. Within football this is one factor which may affect performance in terms of ball roll and bounce and make the pitch more susceptible to wear.
Anaerobic soil conditions is where the soil profile lacks oxygen. Compacted soils can produce anaerobic rootzone as the rootzone will have reduced pore spaces, this will naturally restricted oxygen exchange between these pore spaces. In addition, this will impede the natural drainage of the rootzone. Excess moisture within the rootzone over a considerable period can also lead to anaerobic soil conditions. This can be due to several factors such as the rootzone reaching saturation point – where all easily drained pore spaces between soil particles are permanently filled with water. Significant saturation of the rootzone during the growing season is considered to be a period usually one week or more, this can lead to Blacklayer. Blacklayer occurs when aerobic bacteria cannot survive. This leads to anaerobic bacteria dominating the rootzone as there is little or no oxygen. Anaerobic bacteria respire hydrogen sulphide. The hydrogen sulphide gas bonds with metal ions such as iron forming the black band in the rootzone known as Blacklayer.
Management Pratices for Moisture Management
One of the most common solutions available to most greenkeepers or groundsmen is to review and adopt aeration practices. There are certainly many aeration practices to choose from, such as: Hollow core, Verti-drain, Air2g2, Scarification and Sarel roll to name a few. These all have a part to play in moisture management, such benefits include:
- Alleviating compaction.
- Creating air channels though the rootzone.
- Improving soil surface drainage for water infiltration.
- Aids surface firmness/dryness.
- Increasing ball bounce and surface grip.
- Aid the breakdown of thatch/organic matter.
Penetrant Wetting Agents
Penetrant wetting agents effectively work by lowering the surface tension of water, which means each water droplet spreads more easily and can penetrate soils more readily. This helps remove excess moisture through the surface thatch layer to keep the surface dry and firm. Once a penetrant wetting agent is applied water moves freely downwards through the rootzone assisting the removal of excess moisture in the rootzone. The removal of excess moisture from the pore spaces is replaced by oxygen. Penetrant wetting agents are certainly worth consideration as part of an all year-round moisture management strategy. The benefits include healthier turf less prone to diseases, a firmer playing surface and oxygenating a rootzone to limit anaerobic soil conditions.