Originally Posted by Skipster
Hang on there, Tex!! You're missing the boat on the N issue. Do we want a supply of N as soon as plants break dormancy? YES!!!
You say you're railing against "conventional wisdom," but you're using such "wisdom" in thinking that N is necessarily antagonistic to root growth. Nothing could be further from the truth! N is needed by all plant tissues. High N applications don't even harm root growth (so long as sufficient moisture is present). I think people get this idea from N driving top growth more than it would drive root growth. But, applying more N won't slow roots down -- they'll grow at the same pace. It's just that you'll haveto mow more while its happening.
The tilth that you keep talking about is more of a soil physical property thing and is important in allowing aeration and water infiltration and drainage in the soil, which promote the biological processes of the N cycle. Humus has a lot of CE sites and holds water well, but is mostly brrken down (definition of humus) and doesn't contribute much chemical fertility.
Again, having available N in the soil at dormancy break will not "burn out" roots or carbohydrate reserves. Remember the 16 essential plant nutrients. N is one of them. N is a critical component of the chlorophyll molecule. If we don't have much of it in the spring, we can't produce the carbohydrates needed to replace those lost due to winter respiration.
If you trying to best set up a turfgrass plant for success as it comes out of dormancy, why would you withhold a nutrient it needs for survival?
Here is a CentroWisco site that has a couple of cautionary remarks about early Spring N apps... I'll find some more...
... Never fertilize in April through early May; you will be fertilizing the weeds that are starting to sprout instead of the lawn
... Returning grass clippings to the turf does not contribute to thatch. Early spring fertilization (April & May), fertilizing four times a year, over watering and pesticide use contributes to thatch. Core aeration in the months of May or September (when the turf is actively growing) reduces thatch build-up. Excess thatch cultures several turf diseases.