You need 60 lbs. of potassium per 1 ton of clovers, alfalfas, chicories and other perennials per acre. If your food plot has a removal of 2 ton of dry matter in 2017 you need to replace 60 x 2 ton = 120 pounds of potassium. If you use 0-0-60 straight potassium, you need to put back down 200 lbs. per acre of potassium in the fall. How do we come up with this? When you look at the 3 numbers in a fertilizer sequence, the first number is nitrogen, the second number is phosphorous and the last number is potassium. 0-0-60 contains 60% actual potassium. So, if you get out your calculator here is the math.
120 actual pounds of potassium removed / .60 (60%) = 200 lbs. per acre of 0-0-60
Here is another fertilizer example. Let’s say you need 40 lbs. nitrogen 40 lbs. phosphorous and 80 lbs. potassium per acre of brassicas. Here is how you could fertilize them. If the local supplier only has 17-17-17, 0-0-60 and 46-0-0 urea here is how you could make it work. First let’s meet the requirements for n and p. We would take 40/.17 = 235 lbs. of 17-17-17 would meet all of the n and p and some of the potassium required. So, I’d spread 235 lbs. of 17-17-17 per acre and use additional 0-0-60. How much 0-0-60 do we need to add?
Using 235 lbs. of 17-17-17 gives us 40 lbs. of potassium. If we need 80 lbs. we still need an additional 40 lbs. of potassium. Take 40 / .60 (60%) = 67 lbs. of extra added potassium.
Hope this helps you all figure out how to apply fertilizers. It will take some repetitions for some of you. Good luck hunting!!!