Recently, Jason Haines, superintendent at Pender Harbour Golf Club, wrote a post on his blog entitled "How Much Nitrogen?". That post was especially interesting because it described in such clear terms how he makes effective use of nitrogen and its relationship to turf growth.
The main benefit that I see from using the growth potential model is producing a healthier plant. Since switching over to this fertilizing method I have seen a huge improvement in my turf health . . . It has been a very enlightening year so far in regards to putting green fertility. Basically everything I learned in college 8 years ago has been thrown out the window. I am now using the MLSN guidelines and have based nitrogen inputs on the growth potential for my climate. I have to say, this new way of doing things is working a lot better than the old way. I have cut my fertilizer budget by 60% and have drastically increased the quality and health of my putting surfaces. Almost all guesswork has been eliminated and I can make fertility decisions with confidence.
If you've been to one of my seminars about turfgrass nutrition or read handouts such as this one on understanding nutrient requirements, you'll know of the important role that nitrogen plays in producing the desired turfgrass conditions, and how we can use a temperature-based growth potential to determine an estimated nitrogen rate for any grass at any location. We can then adjust that calculated nitrogen rate based on turfgrass response and current turf conditions.
The turfgrass growth potential was developed by Dr. Wendy Gelernter and Dr. Larry Stowell at PACE Turf. The growth potential is quite useful in my work and I see it applied successfully by many golf course superintendents who adjust their nitrogen rate based on the growth potential.
As an example of how the growth potential can be used to predict estimated nitrogen requirement (use) by the grass, this chart shows the monthly and annual nitrogen for bentgrass at Vancouver and Osaka and for bermudagrass at Bangkok and Osaka.
Jason mentioned that he was able to get these improvements in turf health and quality while reducing his fertilizer budget by 60%. In my next post, we will look at how much it actually costs to get these results.