how do I figure my fertilizer needs?

[WTA]

I have always left this up to the fertilizer distributer but untill now with these high fertilizer prices, I never paid any attention to what I was paying for and I noticed they gave me different amounts each time I went there. I always told them the same recommendations though as per our soil samples and the same number of acres.

What I want to be able to figure out myself is if the soil sample says I need 60 pounds N per acre then what do I tell the fertilizer distributer in tons for 46-0-0 and 32-0-0? That is all they carry. The 46 is dry and the 32 is liquid.


If someone knows how to figure this stuff out please let me know.


Also, I have just about given up on their spreaders for the dry fertilizer. They tell me they put a ton even in it and how fast I should go and how far apart to drive my rows and it never works out. Not even close. In fact I normally spread it going north south across my field then go look in the hopper and it's still half full so I end up making another pass going east west so I can hopefully have even coverage.
I'm thinking about sticking with liquid from now on because I can control my spray rates with MY sprayer.
Only question is, say I am mixing 32-0-0 with water on about a 50-50 ratio how am I supposed to figure out how many pounds of actual nitrogen that is that I'm putting down per acre?

I didn't grow up farming. Not like this anyway. We had horse teams and grew corn. Now I have modern tractors and hay fields. Big difference. We never had to fertilize that old farm either other than putting the cow manure out on the fields. It had some of the best dirt in the country. Now I'm in West Texas with some of the worst dirt.

 

[burnetma]

OK, let's see if I can make this simple. If not, I apologize.

46-0-0 contains 46% nitrogen by weight or 46 lbs of nitrogen per 100 pounds of fertilizer. In other words, two 50 lb bags of 46-0-0 contain 46 lbs of nitrogen.

So if you need 60 lbs of nitrogen per acre you need to spread

pounds of fertilizer per acre = lbs needed*100/% in fertilizer
pounds of fertilizer per acre = 60*100/46 = 130.5 lbs

Same is true for 32-0-0. It contains 32 lbs of N/100 weight. So if you need 60 lbs/acre...

Fertilizer needed = 60*100/32 = 187.5 lbs/acre

Let me know if I helped you out.

 

[burnetma]

I just finished reading your post. If you are mixing the 32-0-0 with water at 50-50 ratio. Then simply double the rate

You would buy 187.5 lbs per acre, but would apply 2x that amount on the field or 375 lbs per acre, because of the water you added.

Again, I hope this helps.

 

[WTA]

Well, I just got back from the fertilizer store. I actually found a new one that I've never used just two miles away too. I can darn near drive the tractor there.
If my tank was bigger than 100 gallons I would.

We picked up 1400 pounds of 32-0-0 for the 7 acre bermuda field. I'm about to get hot spraying it.

I think I got the math all down now to figure out my spray rate. All I have to figure now is how not to overlap any runs across the field. Or miss any spots.
I have a 20 foot wide Wylie sprayer and a new tractor but even with dye in it I can't see where I just went to save my life. Anyone have an idea to cure that?

 

[burnetma]

Let us know how you make out...

 

[WTA]

Well, I got it out. It took two passes and it was dark so I was driving by my GPS compass last night but I got it. I was running 3.8 MPH and one full tank of 50/50 mix was exactly enough to go from one side of the field to the other. I came back and filled up again and ran the field in the other direction, East West, and now I have 45 gallons left in the fertilizer tank. I can figure this out. Next time I'll mix it a little stronger and cut my ground speed in half then I can get it all out in one pass. I'm going to go spray the remaining fertilizer tonight and I'll go diagonally across the field. On my track map on the gps it looks like I got good even coverage but a much bigger gps unit designed for this sure would be nice. Mine is an old Garmin military unit that I had to hold right in front of my face to drive by. That was fun.

 

[chetlenox]

Don't sell yourself short WTA. GPS-guided "Precision Farming", you are cutting edge!

So what you are saying is that you weren't using this?

Chet.

 

[WTA]

Not even close. I have a old garmin GPS12 that I carried in the service with me. It's been all over Iraq and the Pacific with me. Mine is a civi one that I bought but its the same as the ones we were issued back then. I just wanted to have my own so I knew it was taken care of. My display is only about 2 inches wide and black and white. It's green at night. That's hard on the eyes and the equilibrium when you're doing big circles like that.

I just had it on the coordinates screen with a scrolling compass at the top. I kept my eyes on the compass and kept within 1 degree of true north south east or west depending on which way I was going. It helps but I really need one meant for a tractor like the one you showed. It's just way out of my price range right now. I have to get a few cuttings in and pay some bills first.

 

[chetlenox]

WTA,

I'm doing the same "let's make some money on this hay so I can buy the next piece of equipment" thing myself... only it's for the baler. So rest easy that you are already a step ahead of me.


Chet.

 

[WTA]

It's nice being self sufficient now. No more asking neighbors for help. I love it!!!

Now if I could just get my kid motivated to help pick up bales. If this teff hay comes in like I'm expecting well be close to 4000 bales a month here on just 23 acres. I hope. My next cutting on this half where I have the giant bermuda and alfalfa should be over a thousand bales now. I am keeping my fingers crossed.