Comparing Costs Of Traditional Rock Fertilizers To Poultry Litter

Just how high can fertilizer get? Do we have other options? What about poultry manure?

I released this article in 2017 and again in 2020. I thought it would be a relevant one to release again with current prices on the rise as I am still getting questions asked in my counties about this issue.

I have often wondered and have been asked several times about the dollar value of poultry litter products as they relate to the cost of traditional rock fertilizers. I myself have used poultry litter in the past with mixed results.

Please keep in mind, the following bits of information:

1) Poultry litter is not often tested for analysis so guaranteed percentages of N-P-K are not readily available.

2) Poultry litter is not consistent, as it may or may not contain more filler than manure, at any given time. (Ask the provider if this is a de-crusting or is this a total clean-out of the house?)

3) Availability and delivery of poultry litter are based on the time of year and house clean-outs.

4) Some litter is composted while others may come straight out of the barn, which, at times, may cause a few problems. Composted is better.

5) Understand there may be a few additional benefits to applications of poultry litter other than fertility such as increased microorganism action and an improved carbon ratio.

Let us assume, for mathematical comparison purposes, the test analysis results for poultry litter would be 35-35-35 per ton. If one wishes to dispute this point, then ask for a test. Remember the test will only be for the load at hand, as litter is not usually consistent. You can still use the same method to calculate your own results with your test results. Using the suggested application rate of two tons per acre poultry litter (70-70-70), what would be the break-even point if you were to choose traditional rock fertilizer over litter.

The following current fertilizer prices were obtained through local fertilizer dealers and used to calculate the following (prices provided by Hawks Fertilizer Bolivar, Mo., 2/25/2022)

These were the prices in 2020:

DAP 18-46-0 $441.60/ton .2208/lb Ammonium

Sulfate 21-0-0-24 $357.80 .1789/lb Urea

(Treated) 34-0-0 $490.23 .2451/lb

Potash 0-0-60 $372.00 .1860/lb

And these are the prices today:

DAP 18-46-0 $963.20/ton .4816/lb Ammonium

Sulfate 21-0-0-24 $800.00 .4000/lb Urea

(Treated) 34-0-0 $1026.97 .5134/lb

Potash 0-0-60 $864.00 .4320/lb

Working to solve the P level first, as DAP also carries N, the following was determined: 70lb/.46 = 152.17 lbs of DAP (18-46-0) will meet the need. This also provides 27.39 lbs of N (152.17 x .18 = 27.39) which can be subtracted from the N yet needed. 70 lbs of N needed minus 27.39 lbs already applied through DAP leaves 42.61 lbs yet to be obtained.

Working to solve the additional N requirement, using Ammonium Sulfate (21-0-0-24) as our source, the following was calculated. This also adds additional amounts of sulfur to your soil as well which can be a good thing from time to time. Urea (treated), as the N source, might make it cheaper but no sulfur would be added. Coated Urea has a better release period of nitrogen over a longer period of time than poultry manure. (Volatility)42.61lbs/.21 = 202.9 lbs of ammonium sulfate added to the mix. Both N and P are now met.

Last is the K element. Potash will be used to round out the blend.

70lbs/.60 = 116.66 lbs of Potash will be needed to complete the comparison.

The cost of these items are as follows:

DAP: 152.17lbs x $.4816 = $75.70 Ammonium

Sulfate: 202.90lbs x $.4000 = $81.16 Urea: 125.32 lbs x $.5134 = $64.34

Potash: 116.66lbs x $.4320 = $50.39

Total: (Fertilizer only) 471.73lbs/ acre $207.2

Total: (Fertilizer only) 394.15lbs/ acre $190.40

Spreading rate/acre: $ 10.00 Spreading rate/acre: $ 10.00 Grand Total/acre: (Spreading and Fertilizer) $217.2 Grand Total/acre: (Spreading and Fertilizer) $200.40

The Grand Totals in 2020 were $96.59 and $91.00 respectively.

The Grand Total in 2017 for DAP, Amm. Sulfate, and Potash was $91.89.

Another area of concern may be tons delivered per load. In rock fertilizer blends, each element is weighed to complete the mix, matching your soil test recommends. After all, when you receive a load of corn or price your hay at “X” amount per ton, you usually weigh the load. If you purchase a load of poultry litter you might want to ask for a weigh stub. A little extra is to your advantage but less is not. Without a test analysis or a weigh ticket, you are only guessing at the load.

At this rate, two tons of poultry litter delivered and spread, per acre, should be equal to $217.25/$200.40 per acre of rock fertilizer. Anything higher than this is more than the cost of rock. So, are the additional benefits discussed earlier worth it? Also, keep in mind that manures react somewhat differently than rock fertilizer when applied to your fields.

Maybe poultry litter has definite advantages at times; just make sure you are getting what you pay for.