Originally Posted by Smallaxe
This is the summary at the end of the article and perhaps the thing to do would be to reflect back into the research and see where these claims have merit and where they are deficient...
... "Late-season fertilization lengthens the fall/winter green period and enhances the rate of spring green-up without stimulating excessive shoot growth, thus allowing the turf plant to maintain higher levels of carbohydrates than when spring/summer fertilization is used. This provides both aesthetic and physiological benefits to the plant and customer/client. Nitrogen applied during early spring increases shoot growth rates and decreases the levels of available carbohydrates in the plant, resulting in depressed root growth rates. Late-season nitrogen applications have no similar negative effects on root growth and, in fact, increase root growth during mid winter to early spring. Better carbohydrate storage and root growth ultimately result in a more stress tolerant turfgrass plant during stress periods. No winter damage or snow mold injury occurred as a result of late-season nitrogen applications in OSU research. ..."
I look at this as an explanation as to "Why", the SpringTime natural growth is healthy versus the application of water soluable N to throw it off its normal development,
What is it in the Summary that you don't agree with???
I agree with all but the part about snow mold. It's only from my experience though that when we have more fall rainfall here, more Potassium is lost and on the low end of sufficiency for healthy turf/roots/storage. Then I saw more snow mold issues as a result.
Penn State and Rutgers talked about 2/3rds of the annual Nitrogen to be applied in the 2 fall apps......1 lb when temps cool off and cool season grass is out of summer dormancy and sufficient available water, and then the late season application that was 1- 1.5 lbs N depending on the annual turf "total input". KB needs more than PR, Fescue or TTTF. You just did the math, and adjusted rate accordingly.
In the University studies about late season Nitrogen, I do not recall discussion of "test plots" Essential Macro nutrient levels of P,K,S in Low-Med and High ranges, and the different effects had on turf WITH the Late Season Nitrogen applications. I think in the "Test Plot" world (enough Ca,Mg,P,K,S) in a soil with good CEC and not too much water/leeching, just Late Season Nitrogen would not pose a snow mold issue.
Some Professors input(s) to our findings would be helpful in this thread.