If it sounds too good to be true it usually is. Sage advice.
What kind of fertilizer goes on at only 2 pints per acre?? NONE that's what! This person is selling an AMENDMENT or something, an additive, not true fertilizer. Here's why--Say you're putting on 17-17-17 dry fertilizer at 100 pounds per acre. That's 17 ACTUAL pounds of Nitrogen, 17 ACTUAL pounds of Phosphorus, and 17 ACTUAL pounds of Potassium per acre. Now if your soil test calls for, say, 40 lbs. N, 34 lbs. P, and 20 lbs. K per acre, let's say you decide to put 200 lbs. 17-17-17 on that would be 34 N, 34 P, 34 K per acre.
Now let's look at liquid fertilizer. When I row cropped that was mostly what I used. Liquid aqueous ammonia is 32-0-0. That means that 32 lbs of actual N per 100 lbs. liquid. Phosphate is usually 11-37-0, since the phosphate is dissolved in water and ammonia. It has 11 pounds N and 37 pounds of P in it. Potassium is usually (if I can remember right) 0-0-25, something like that. So, going back to our example, if your soil test calls for 40 N, 34 P, 20 K, and you put 100 lbs. per acre of liquid fertilizer in a blend containing 32-0-0, 11-37-0, and 0-0-25, it would theoretically put down 43 lbs. N, 37 lbs P, and 25 lbs. K per acre. The 32 units of N are added to the 11 units in the 11-37-0. BUT it's not that simple. This is just an example because in reality, when you mix liquid fertilizer it is usually in weird proportions and sometimes you have to add water to keep it from crystallizing or precipitating and settling out. Those calculations can get pretty involved and when I used to get a lot of fertilizer he did it on a computer (OLD computer) and then gave me a mix sheet to take over to the batch plant. Here's a mix sheet I found. The soil test recommended 70-15-0 for the cotton crop. My dealer fed it into the computer which said 250 lbs. acre of a mixture of 28-6-0-1S (1 unit of sulfur added as a micronutrient that I always put out) was the best mixture. The batch mix consisted of 619 gallons of 32-0-0, 117 gallons of 11-37-0, and 25.5 gallons of 12-0-0-26 (sulfur slurry) which had a batch weight of about 8500 pounds at 11.16 lbs./gal. and cost $211/ton in 1995.
What it boils down to is price per unit of N. Some forms of N are cheaper than others because some have more available N than others. You have to do a little checking and a little figuring to see the actual cost of N per pound and how much per acre. The ONLY fertilizer that MIGHT be put out at 2 pints per acre is either a micronutrient or some type of foliar fertilizer and even those (when spoonfeeding cotton became popular a few years ago) you put out like 2-5 gallons of fertilizer per acre in 20 gallons of water sprayed over the top, if I remember right from the extension meetings.
If you want to save money on fertilizer your best bet is to plant a good, well inoculated winter legume that will fix N out of the air for you for free (less the cost of seed, inoculant, and planting) and plant grasses that have lower fertilizer demands like bluestems. You'll still have to topdress a little N and your P and K requirements but getting most of your N for free from legumes that will produce some good grazing or hay will save you more than any "snake oil" somebody might try to sell you. JMHO. Good luck! OL JR
