November 6, 2012

Today lime was applied to the fairways. Soil tests taken late summer revealed that the pH had dropped over the past few years and a correction was needed. The availability of certain nutrients to a plant is directly dependent upon pH. Acid soils tie up some nutrients while basic soils tie up others. Plants thrive with and/or without certain nutrients which is why the soil pH is very important to what particular plant is being grown. Turf – most turf – grows best at a pH of 6.5.

That seems simple enough, but an ideal pH is not always ideal. For example, some diseases, summer patch in particular, are more prevalent and destructive at a pH of 6.5 than a lower, or more acid pH. So we have to thread the needle very carefully to balance pH to get the best environment for the turf and the worst for the fungi. For our plants and disease history, a pH of 5.7 to 6.0 has continually given us the best growth and least disease pressure. This best case pH may be different for another course.

Not all lime is the same. There are two common types - high calcium lime, and high mag lime, which contains a high percentage of magnesium. The level of these nutrients found in the soil test will determine which type should be used. Sometimes the soil needs one or the other, or like in our case, we need to use both. To that end, today we are spreading high cal lime as half our lime requirement, and early next spring we will spread an equal amount of high mag lime.

What causes our soils to need liming every so often? Why does pH drop? Certain fertilizers and nutrients cause acidity, as well as irrigation water (yes, we keep an eye on that too!), rain, types of organic matter (like the mulched tree leaves), topdressing materials, etc. Soils are ever evolving, which is why it is so important to monitor them and make nutrient and pH corrections very regularly.