Nitrogen

I’ve been making estimates of N mineralization from soil organic matter for the past few years using the method described by Gilmour and Mauromoustakos in Nitrogen mineralization from soil organic matter: a sequential model.

Phil Collinson asked an interesting question: when calculating N inputs, do greenkeepers account for N added outside of fertilizer? Greenkeepers - when calculating N inputs for the year do you account for N outside of fert?

In the last ATC update newsletter I included a survey about future video topics. These are the results. Thanks to everyone for the feedback! A topic that has been on my mind and that I want to explain further is N fertilizer and ClipVol.

There’s an interesting article by Espevig et al. on Effects of rolling and N-fertilization on dollar spot and Microdochium patch on golf greens in Scandinavia. rolling a red fescue green two times a week reduced dollar spot by 61% compared to no rolling rolling four times a week reduced dollar spot by 95% increasing annual N on a creeping bentgrass + Poa annua green from 15 to 24 g/m2 reduced dollar spot by 24% but the following spring saw twice as much Microdochium patch on the plots which received the higher N rate There are a number of surface performance benefits that come from rolling, and disease suppression is one of them.

The other day it rained at ATC南店. I knew that the grasses would grow at a faster rate after the rain than they had been growing prior to the rain.

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.

The turfgrass genki level is a way to express the degree to which turgrass is being pushed to grow, or restructed from growing, by the supply of nitrogen.

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.

In part 2, I showed how the ratio of N applied to standard N gives an indication of how much one is pushing the grass to grow. I call that the genki level (GL).