potassium

I talked with Frank Rossi today on the ATC Doublecut. You can watch or listen to the show at the links. We discussed potassium (K) fertilizer, and why there are still recommendations for so much more K than the grass can use.

When I make nutrient recommendations, I recommend a quantity of each element that ensures the grass can get all of that nutrient that the grass can use. I also make the recommendation with a thought about the soil.

Soil nutrient levels change because grass is growing and grass uses nutrients. This change is in one direction—down—because nutrients are removed from the soil as the grass grows. Fertilizer addition and addition of nutrients through irrigation water or topdressing materials can cause soil nutrient content to increase.

After the 2014 GCSAA nutrient survey, I wrote a blog post titled “maybe those that soil test are just more likely to fertilize in general?” I made the case that although they might be more likely to fertilize, there seemed to be an effect of soil testing on that too, at least for K.

Doug Soldat has been posting these spectacular photos every year. See the “related posts” section at the bottom for more of these from past years. When he shared this one, he wrote “stop me if you’ve heard this one before.

I received an interesting question about some soil test results. Hey Micah, I’m just looking at the soil test results again … is there anything to worry about regarding sodium (Na) being higher than potassium (K)?

Doug Soldat joined me for an ATC Office Hours discussion about leaf nutrient analyses (tissue testing) for turfgrass. I’ve embedded the video at the end of this post, link to it here, or listen to the podcast version here.

A colleague from Canada wrote to me with five comments after finishing this ATC Office Hours with Chris Tritabaugh (or listen as a podcast here). Just listened to your talk with Chris and wish I had the where about to attend it live, as I would have kept the chat room real busy!

This is a good one. Sand rootzones with low cation exchange capacity (CEC) don’t have a large amount of exchangeable potassium (K), for the simple reason that sands have a low CEC.

You’ve probably listened to one of my seminars in which I explained why conventional nutrient guidelines for turfgrass are broken. Jackie Guevara’s thesis on “Effects of Different Soil Testing Philosophies on Creeping Bentgrass and Annual Bluegrass Putting Greens” is an excellent demonstration of this.