To zinc your pecan trees with my preferred method, you will, of course, need a sprayer of some sort. If you have only a few trees, or if you have a whole orchard of young, small trees, you may opt for an inexpensive pump sprayer although sooner or later, you will find it necessary to 'move up' to a more efficient and easier to use mechanical sprayer. I personally attempt to run my pecan operation in 'the black' and therefore, have generally worked my way up to larger equipment only when the profits from my orchard permit me to 'pay cash' for equipment improvements.
Whatever sprayer you choose to spray your zinc with, keep in mind that you will either need a high volume of pressure to reach to top parts of your pecan trees or will need 'some height' to elevate you and the sprayer to a level of your trees' branches. If you choose a smaller sprayer, you may find that riding in the back of a pickup up and down your orchard rows will work nicely. I rig my sprayer onto our old Farmall 560 and take off down the rows, spraying each tree with a zinc solution.
Ah yes, the zinc solution. Zinc Sulfate can easily be found at most home and garden stores in quantities as small as one pound. It is a powder that dissolves well in water, and a little actually goes a very long way in terms of applying it to your trees. Liquid Zinc is also available, however, it tends to crystallize over a period of time and I've found myself discarding jugs of zinc. I personally recommend the powdered zinc because of this.
Zinc applications must be at the top of your list of priorities when it comes to pecan orchard management. Not near enough attention is given to the importance of zinc in the production of pecans. Zinc is an inexpensive and easy to apply nutrient, and the benefits reaped are more than worth the expense and time it takes to supply your pecan trees with one of the best-kept secrets to pecan production success. Zinc your pecan trees!