For my work, I'm doing a comparison of organic fertilizers available. Bottom line is always cost of course, but relating to the cost would be the potency of the fertilizer, how much would be needed, etc.

Little background first. The lawns we have here are bermuda and a lot of it, about 45 acres I'd say. Currently the fertilizer of choice is Organic Gem Liquid Fish Fertilizer (3-3-3). In my opinion though, I feel this fertilizer is inadequate for bermuda, costs a ton of money, and smells horrible for being a public area.

I know one of the main ideas behind organics is protein content. I've used this idea on my own lawn and that's why I chose soybean as my main choice of fertilizer, being 47% protein I believe. I'm also trying to work on collecting coffee grounds on a mass scale.

My question is what are protein levels of used coffee grounds and liquid fish fertilizer? I've been looking all over for these numbers but they are hard to come by.

To figure nitrogen from protein, one would divide the protein percentage by 7.

To find the opposite, would one simply multiply the nitrogen content by 7?

The fish fertilizer would be about 21% protein?

Coffee grounds about 14% protein?

Not necessarily. That wouldn't work if the material in question has water-soluble nitrogne in it, so it would be bad for Milorganite. It's about 21% protein, 2% water-soluble N. That 5% N wouldn't reverse well.

It should work for fish fertilizer and coffee grounds, though, as I don't believe either have soluble salt-based N in them.

I did find an analysis of Starbucks coffee and its nitrogen level was 2.28. Multiplying it by 7 would make it close to 16% protein then.

Can I ask why 7? I'm a novice when it comes to the organics, so that's why I come here to ask these questions.

Vince92183 wrote:Can I ask why 7?

Cause that is what my search of Bestlawn returned, thats why!

Google actually gives the factor as 6.25 instead of 7, so I'd also like to learn.

This is where I butt the heck out and wait for one of the brains to chime in. I just regurgitate where applicable.

Michael Wise wrote:

Vince92183 wrote:Can I ask why 7?

Cause that is what my search of Bestlawn returned, thats why!

Google actually gives the factor as 6.25 instead of 7, so I'd also like to learn.

This is where I butt the heck out and wait for one of the brains to chime in. I just regurgitate where applicable.

Nitrogen content of protein has to do with the relative proportion of Nitrogen in the amino acids that make up the proteins. In truth, different amino acids have different proportions so the actual ratio will vary based on the source material. All that being said, it turns out that using a multiplier of 6.25 works well as the overall average Nitrogen content of most proteins is 16%.

Now my next question, mainly for a cost analysis. I usually use the formula following formula to figure out how much soybean to put down per 1000 square feet:

(Nitrogen Analysis / 100) x Pounds = 1 Pound of Nitrogen

It comes out to around 15lbs of soybean, but I usually put about 20lbs. I do monthly feedings to achieve the 1lb of nitrogen a month.

Anyway, how do you do this for the liquid fish fertilizer? Is there a formula for liquid?

Nitrogen content of protein has to do with the relative proportion of Nitrogen in the amino acids that make up the proteins. In truth, different amino acids have different proportions so the actual ratio will vary based on the source material. All that being said, it turns out that using a multiplier of 6.25 works well as the overall average Nitrogen content of most proteins is 16%.

If you care to study this for the details, look up the "Kjeldahl Method".

The conversion factor is 6.25, which represents 16g of Nitrogen per 100g of protein.

So, if the organic source is 20% protein, it is 20/6.25, or 3.2% N.

If the organic source has a Nitrogen percentage of 3%, it is 18.75% protein.

andy10917 wrote:

Nitrogen content of protein has to do with the relative proportion of Nitrogen in the amino acids that make up the proteins. In truth, different amino acids have different proportions so the actual ratio will vary based on the source material. All that being said, it turns out that using a multiplier of 6.25 works well as the overall average Nitrogen content of most proteins is 16%.

If you care to study this for the details, look up the "Kjeldahl Method".

I still try to forget organic chemistry lab...

Vince92183 wrote: Bottom line is always cost of course...
The lawns we have here are bermuda and a lot of it, about 45 acres

Pardon me for saying this, but you are out of your mind thinking organic fertilizer for this much area, not to mention would need a full time crew working 7 days a week maintaining it.

But to answer your question Soy Bean Meal is the best bang for the buck requiring 15 lbs/ft2 so for 45 acres would requires 30,000 pounds per application, or based on current wholesale prices of bulk SBM is $6000, or ab out $10,000 retail in the 50 lb/bag. You can buy bulk Urea @ $3500...

TW, I'm not trying to argue that SBM on 45 acres is practical, but Urea is not a great comparison. Too simplistic. SBM is 7-2-1 NPK even if you ignore the OM implications, other nutrients, etc. At your stated rate of 15 lbs, you'd get .3 lbs of P and .15 lbs of K. And the Urea would be gone from the soil way faster than the SBM. A fairer comparison would be a synthetic 46-16-8 time-release (if there were such a thing).

BTW, I think that you meant 15 lbs/Kft2, not 15 lbs/ft2.

Vince still needs an answer on the cost of fish fertilizer to apply an equivalent number of pounds of protein per 1,000 square feet. His fish juice supplier recommends weekly apps of 1 gallon per acre. This is 3 ounces per 1,000 square feet. In my opinion they may as well not apply it at all. I don't see how 3 ounces of a watered down liquid (3% nitrogen) can equate to 15 pounds of soybean meal. But he still needs to compare cost. How much liquid fish breath would he need to apply to equate to 15 pounds of soybean meal?

I'm guessing that gallon of fish juice weighs 10 pounds (4,536 grams) and contains 3% nitrogen, then at 3% that gallon has 136 grams of nitrogen. Multiply that by 6.25 and you get 850 grams of protein per gallon of fish breath. Multiply that by the grams to pounds conversion (Google) and it comes to 1.87 pounds of protein per gallon of fish juice.

Soybean meal is about 40% protein. When you apply 15 pounds per 1,000 square feet you are getting about 6.2 pounds of protein.

For bermuda we usually talk about how much fertilizer should be applied every month. In order to get 6.2 pounds of fish protein you would have to apply 3.32 gallons per 1,000 square feet. That would be per month so you could cut that amount by 4 for weekly applications. For weekly applications that would be about 100 ounces per week. But they are applying at a rate of 3 ounces per 1,000 square feet. At the risk of confusing everyone, that is about 3% of what it should be assuming my assumption about 10 pounds per gallon is fairly close and I did not confuse myself in the conversions.

Somebody please check my math. Although I have considerable math background, I always stumbled my way through concentrations and percent with respect to chemistry in liquids.

TW, Vince has very little say in what gets applied. He is a lowly university student working for handouts (tuition) for the common area grounds on campus. He's been arguing against the use of the expensive fish fertilizer for some time to deaf ears. Being a university they almost have to be 'green' in their approach. Organic is the name of the game. The guy who sells it is a slick operator who is selling the most expensive approach to organics I can think of. He also sells them expensive compost made from donated feed stocks from the university.

andy10917 wrote: Urea is not a great comparison. Too simplistic. SBM is 7-2-1 NPK even if you ignore the OM implications, other nutrients, etc. At your stated rate of 15 lbs, you'd get .3 lbs of P and .15 lbs of K. And the Urea would be gone from the soil way faster than the SBM. A fairer comparison would be a synthetic 46-16-8 time-release (if there were such a thing).

BTW, I think that you meant 15 lbs/Kft2, not 15 lbs/ft2.

I did mean 15-lbs/Kft2, and urea is a very good comparison if using a slow releases 20-5-10 or 15-5-10. As David points out you would have to be a mufti-millionaire to use fish emulsion and is extremely fast release. Faster than blood meal.

Dchall said it, I have really little say in what is used but it definitely has to be organic. I just know fish is not efficient at all and something else is needed....which brings me to soybean.

Thanks for all the responses, it gives me something to work off of.

Dchall_San_Antonio wrote:TW, Vince has very little say in what gets applied. He is a lowly university student working for handouts (tuition) for the common area grounds on campus. He's been arguing against the use of the expensive fish fertilizer for some time to deaf ears. Being a university they almost have to be 'green' in their approach. Organic is the name of the game.

Last time I was in school Urea was an organic compound along with sulfate of potash and rock phosphate

But it's cooked up in an evil chemical laboratory and all that. It never bothered me, but does bother some people.

Wikipedia says...

For use in industry, urea is produced from synthetic ammonia and carbon dioxide. Large quantities of carbon dioxide are produced during the manufacture of ammonia from coal or from hydrocarbons such as natural gas and petroleum-derived raw materials. Such point sources of CO2 facilitate direct synthesis of urea.

It seems like a waste of natural gas to make it.

It is, but so is flaring off a well, which they do all the time. Natural gas is so common and so cheap that we don't conserve it much. There's no money in doing so.

The gas you see in a well flare is natural gas contaminated with sulfur, hence the bright orange flame. It is burned off for a couple reasons. One is that sulfur dioxide is heavier than air and would quickly kill anyone in the general area. Second reason is it corrodes everything it touches. Sweet natural gas normally burns with a blue/invisible flame.

Sorry this is drifting off topic...

Good info though.