phosphorus

On February 28, I planted ‘Wana’ manilagrass as two node rhizomes in sand-filled pots. All pots have had irrigation and rainfall. One pot has not been fertilized. One has received only N from urea.

I was reading the “Cultural Aspects of Disease Management” chapter in Management of Turfgrass Diseases by Dr. Vargas and came across this gem about soil pH: “Most of the literature tells you that the soil pH should be maintained at the optimum level for turfgrass growth (between 6 and 7).

The MLSN guideline for phosphorus (P) is 21 ppm. I usually recommend enough P fertilizer to keep soil P, as measured by the Mehlich 3 extractant, from dropping below 21 ppm.

After last week’s post about the soil test levels where P deficiency symptoms were seen, Paul Johnson wrote to remind me about another experiment: “This is always a topic of interest to me, beginning with the study I did in the early 2000s.

When I see a photo like the P deficiency one shared by Ben Pease (see photo below), I am really curious to know the soil test levels of the element.

Phosphorus is an essential element for healthy turfgrass plants, but phosphorus can also contribute to algal growth in natural water bodies, so turfgrass managers should try to apply only the amount of phosphorus that is required by the grass.