phosphorus

The usual way of thinking about soil nutrients and turf quality is something like this: when the amount of a soil nutrient is low, the turf quality won’t be as good as it would be if that nutrient were more abundant in the soil.

This is one of the many interesting things I’ve been working on recently. A standard soil test for turfgrass is taken to a 10 cm depth (4 inches below the soil surface).

Normal range of test results Soil test phosphorus (P) is present across a wide range in golf course putting green rootzones. I looked at ATC data from putting greens for the past five years.

When a creeping bentgrass green is sixteen years old, do you expect to find some Poa annua in it? I do. When I see greens that age without noticing any Poa plants, I pay attention.

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.

After I wrote this post about the differences in P fertilizer recommendations when using different methods for soil test interpretation, I heard from some readers that it seemed I was taking something simple—MLSN—and making it seem complicated.

Daniel Hahn and Romain Giraud wrote an article on LinkedIn about fertilisation decisions based on MLSN and STERF’s precision fertilisation (SPF). If you are at all interested in this topic, I hope you’ll read their article.

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.

These pots of variegated tropical carpetgrass (Axonopus compressus) received an application of granular 16-16-16 fertilizer twelve days before this photo was taken. The grass on the right responded with a lot more growth than did the grass at left.

On February 28, 2020, I cut some Wana manilagrass rhizomes to a two node length and planted those two node rhizomes in four sand-filled pots. After eight days, I applied the first fertilizer treatment.