Too Much Rain

2014 has been a particularly wet year thus far, and the cumulative effects of this moisture are starting to show up. If given the choice of having to deal with either wet or dry weather conditions, I would choose dry conditions every single time. Dry conditions allow us to supplement moisture with irrigation, whereas our ability to remedy wet conditions is extremely limited.

To allow the plant to properly perform its metabolic functions, the soil must be able to breath. Saturated soils do not have any capacity to exchange the gasses used or produced by the plants metabolic processes. Saturated soils can result in decreased levels of O2, which is the gas that plays a role in hundreds of metabolic processes. In addition, a buildup of toxic compounds such as sulfides and CO2 have been reported in saturated soils.

Denitrification is a symptom of saturated soils which we have observed on the golf course this year. Denitrification is a process that turns nitrate into nitrogen dioxide and dinitrogen gasses that are unavailable to the plant. This process is catalyzed by microbes that function in low soil oxygen environments.

Suspected denitrification and low soil oxygen symptoms

Here you can see the exact path the water takes as it drains.

The two photos above show the same areas after a few days of dry, cool weather and an application of a soluble fertilizer.

Saturated soils usually result in higher summertime soil temperatures. Although wet soils may take longer to heat up due to water’s higher specific heat they also take much longer to cool down due to water’s higher heat capacity. This can result in a sustained soil temperature above preferred  levels for optimal turf health.

Another issue we encounter with an abundance of moisture is disease. Wet and warm weather conditions create a prime environment for most turfgrass diseases. An ill-timed rain event could force an unplanned fungicide application, costing the golf course tens of thousands of dollars.

An additional nuisance effect of all the rain has been the need to keep golfers on the cart paths. At this point, soils are so saturated that even small amounts of precipitation have forced us to employ cart restrictions. I understand that this is an inconvenience and can really slow down play, but because of all the things I have touched on above, the plant is in a weakened state and is less capable of handling traffic stress. It is important to keep all carts off the turf until the surface has dried out.

If water is being displaced by the cart, it's still too wet.

An excellent question I was asked last weekend was "Why are we on paths and another particular course is not?" There are a number of factors to deal with in this situation. Moisture totals from storms can vary greatly from place to place. We have had storms this year that have dropped 7" in some parts of town, and “only” 2" in other parts of town. We have had situations in the past where one side of the course had significant rain totals and the other half did not. In this case, the course we were being compared to was 26 miles from our location and received 0.12" of moisture vs. our 0.50". The difference between cart restrictions and no restrictions could be as small as a couple tenths of an inch so these seemingly minute differences are important.

Also,  keep in mind that all golf courses have different soil types, topography, and drainage systems, which influence their ability to handle water. Some courses topdress fairways, which allows the water to percolate through the profile and away from the surface faster. And, some courses don't have cart paths, so cart restrictions aren't an option. I can promise you that cart restriction decisions are my least favorite decision to make. I thank you for your patience throughout this wet season and hope it starts to dry up a little bit.