Doc, are you using the cationic drench as a replacement for energy after week 4?
Ps
No.
Here's an email I got from the lab. This isn't a direct answer to your question, but the answers you seek are contained therein in germ form......
NPK....all nitrogen is "N." It's all the same once the plant breaks it down, right?
Doc Bud,
"Wrong!" says Dr. Reams.
"Nitrogen can be growth energy or reproductive energy depending on molecular configuration."
When nitrogen is in the nitrate form it creates growth energy in plants and soil. Reproductive energy comes in the form of ammoniacal, urea, or organic nitrogen. This dual form of energy for nitrogen makes it the most confusing element to consider when looking at energy.
A basic principle to always remember is that plant growth is all about energy.
You create this energy by reacting growth energy against reproductive energy according to the crop being grown.
Let's take a few examples to clarify this concept. We had a wheat grower who decided to spray his wheat with a few gallons of liquid calcium nitrate. Unfortunately this resulted in a significant yield decline. Fortunately International Ag Labs did not suggest this.
So what happened?
Liquid calcium nitrate is a double growth energy fertilizer. Both calcium and nitrogen in the nitrate form push plants and soils with growth energy. Regrettably the farmer sprayed his wheat just at the time the kernel count was being determined. The growth energy from the calcium nitrate pushed the wheat plants more toward growth energy and away from reproductive energy. What the plants really needed was a reproductive spray to increase kernel set.
Here is another example: A grower with a field of canning tomatoes sought to maximize his harvest of tomatoes all at picking time. To do this he kept his soil on the growth side longer by using growth energy products such as calcium nitrate and potassium nitrate. The result were large tomato plants and thick stalks but not a tomato anywhere. The canning company field rep was getting worried.
At the right time the farmer switched his soil from growth to reproductive and turned his field yellow with blossoms overnight. How did he do this? By using reproductive fertilizers and foliar sprays. These caused the soil and plants to switch from growth to reproductive. How can this be done? Simple - broadcast some ammonium sulfate, 11-52-0 or urea. Then spray the plants with a dilute reproductive spray made from household ammonia, phosphoric acid, vinegar etc. The broadcast switches the soil while the foliar spray switched the plants.
Once a large bunch of tomatoes were set and beginning to develop, the farmer switched back to growth energy dominance. Why? Because growth energy is also bulking energy. Now the farmer wanted to size up the tomatoes. By keeping growth energy dominant he was able to stop new blossoms from developing. What was the end result? A large harvest of tomatoes all ripening at nearly the same time.
Last example: You manage conventional turf. What nitrogen source should you use? The standard practice is to use urea. Urea is a 100% reproductive energy. Turf is a crop that needs growth energy dominance. This means urea is the exact opposite energy of what should be supplied. Organically managed turf using compost or some other organic nitrogen does the same thing. Too much reproductive energy. The answer is to use calcium nitrate.
So is nitrogen just nitrogen? No it is a very specific energy that can influence the soil/plant in the direction you wish.
Usually, you can't do both. If you feed the plant directly, it doesn't feed the biota anymore and the soil dies off.