Productive pecans are heavy N feeders. I usually use triple-13 or just ammonium nitrate...kinda depends on what I've got on hand when I get around to doing it.
Lots of info from universities on proper fertilization regimens, soil/leaf testing, etc.
Here's one: https://www.uaex.edu/publications/PDF/FSA-6131.pdf
Zinc may or may not be needed, depending on your location and cultural practices.
Split applications in Mar, Apr, May, June is what I usually shoot for... (but it doesn't always happen)
My dad used to tell me that you could sprinkle a can of Red Devil lye out around the drip line of a big old senescent pecan tree, and it would stimulate it to come back into production.
5-10 years is about in line for most grafted
pecans to begin bearing decent crops...seedlings quite a bit longer. The kids and I planted about 400 2-yr-old pecan seedlings in a CRP riparian bufferstrip back in 2000. Granted, they've received no care other than 2X/yr mowing, but most are approaching 20 ft tall, and maybe 1/4 of them are beginning to flower... a couple produced a few nuts in 2014 & 2015...but the critters got 'em before I did.
TT, there are plenty of pecans around; you just have to look. We're in the northern/midwestern pecan belt. Several of the really good pecan cultivars for this area - some of which have been used extensively by USDA/ARS in their pecan breeding program - originated in the Green River delta, up around Owensboro/Henderson KY. Here's a short article on one of the best: http://northernpecans.blogspot.com/2011 ... hters.html