This can seem a bit abstract, the whole growth ratio thing. In this post, I go step-by-step through the reasoning behind this, and explain exactly which problem this solves.
There’s a common question that people have when they start measuring the exact amount of clipping volume.
A question came up about optimum clipping volume and whether that quantity of clippings changes by season. That amount must change for any location at which there are seasonal changes in the weather.
Bentgrass grows more—or at least it produces more clippings for a while—when temperatures are higher than optimum for net photosynthesis. This means that you’ll typically see more clippings when the temperature is above the optimum for cool-season grass, even though the growth potential (GP) goes down at those high temperatures.
The PACE Turf topdressing rate spreadsheets have been updated with a new default starting value for monthly maximum topdressing sand.
US units spreadsheet
Metric units spreadsheet
I watched the Greenkeeper App meeting about organic matter, and I recommend you do too. The video has Doug Soldat, Bill Kreuser, and Roch Gaussoin talking about soil organic matter, rootzones, sand topdressing, and turf performance.
Does this sound about right?
Matching sand topdressing to the growth of the grass works out pretty good when applying 1 cm3 of sand for every 1 cm3 of clipping volume.
I’ve sometimes explained the temperature-based turfgrass growth potential (GP) of PACE Turf in relation to the grass conditions at the Masters Tournament.
The playing conditions at the Masters are superb, and the cool-season grass in that season is growing at near optimum temperatures.
I put the series of genki level (GL) blog posts together into this 17 page pamphlet.
The pamphlet explains how one can calculate the genki level from the actual N supplied as fertilizer compared to a standard amount of N for any time duration.
In this series of posts, I’ve showed how one can start with temperatures and go all the way to a standardized comparison of growth in response to nitrogen supply. In this one, I want to emphasize which of these are real, which aren’t real but are useful, and to make an argument that this is a lot easier than it might seem.
The amount of nitrogen (N) supplied over a certain time duration, compared to a standard amount, is what I call the genki level (GL). And the amount of clippings harvested over a certain time duration, compared to a standard amount, is what Jason Haines calls the turfgrass speedo.