Fertilizer dry mass percent?

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Fertilizer dry mass percent?

Post by Green » November 30th, 2021, 6:17 pm

How does fertilizer dry mass percent relate to the analysis percentages? I'm seeing dry mass percentages (especially from organic sources) listed more often on bags lately. In the one or two products I've seen it listed for recently, it seemed to be about the same as the %N from that organic source, but I'm not sure if there is actually an association between the two.

I'm guessing this is something that has been used in compost analyses for a long time, but I didn't come to lawn care after having done other types of gardening first, so I'm not familiar with it, as I'm sure many here aren't.

Thanks.

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Re: Fertilizer dry mass percent?

Post by MorpheusPA » November 30th, 2021, 7:42 pm

Good question. In the case of--say--ferrous sulfate, it's always accounted for. Ferrous sulfate monohydrate is 30% iron by weight. Ferrous sulfate heptahydrate (the most common form) is 18% iron by weight. But you do need to do the research.

For fertilizers in a bag, they must always be guaranteed by weight (by law), so if it says 5% N, it's 5% N minimum, by weight. Period.

When we estimate on an organic, we're using an average. For soy, the 6.25% N is by normal weight, which is typical for soy--a typical analysis is 13% moisture.

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Re: Fertilizer dry mass percent?

Post by Green » November 30th, 2021, 10:16 pm

One situation where this labeling is helpful is in fertilizers combining organics and synthetics. Let's say we have the following Nitrogen content listed:

Total N: 22% *
--10% Ammoniacal
--11% Urea
--1% WIN

Nitrogen derived from:
anhydrous ammonia and sulfuric acid; polymer coated urea; protein hydrolysate** (manure digestate, food digestate, and biosolid digestate).

* 15% slowly available N from protein hydrolysates, PCU, and WIN.

** 11% of the fertilizer dry mass is composed of matter derived from protein hydrolysate.


Question:
22 (total N) minus 11 (urea N) = 11 (same number listed in dry mass for the organics). Is that what you'd expect per labeling standards? Or is it a coincidence, and that value (11 in this case) might vary by organic source and won't always match the math? I'm thinking the latter, because 15-11=4. That would imply that only 4% of the slow release N is not urea. Not sure how that relates to the 11% dry mass number.

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Re: Fertilizer dry mass percent?

Post by MorpheusPA » December 1st, 2021, 5:15 pm

Numbers in fertilizers are always floors as well, so your 5% N organic fertilizer might be 6% or 7% nitrogen if you got lucky, it's just that the lowest assay was (say) 5.98%, so all they can say is 5%. Just FYI.

4% of the slow release being not-sulfur-coated-urea sounds about right for most fertilizers, which may feature a lot of spent grains, cheap ground corn (low N), some soy (higher N) and hydrolized feather meal (very high but very slow N).

I could push it as high as 12%, but you wouldn't be real happy with the fertilizer. I'd either burn the lawn or it wouldn't green up for months (blood meal or feather meal, respectively). Most reasonable responses and ranges will be from 2% to 7%.

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Re: Fertilizer dry mass percent?

Post by Green » December 1st, 2021, 8:28 pm

Morph,

I'm still missing something. Are the 11% dry mass and 4% N (from the label analysis) that I quoted supposed to represent the same fraction/same thing and use the same standard of measurement?

If so, I'm still confused. Dry mass means no water. But clearly there is not 11% N present. It's 4%. Does dry mass actually convey the same standard as the numbers from the N-column in the analysis?

Also: you mentioned hydrolyzed proteins. That was going to be my next question. It seems that protein hydrolysis is what makes the proteins usable as fertilizer. I'm assuming that long polypeptide chains make for poor fertilizer (take ages to break down) and that's why they hydrolyzed them?

And it seems that there are two main ways to naturally hydrolyzed proteins...aerobic composting and anaerobic digestion. It seems the latter is more common in fertilizer manufacture because it preserves a higher nutrient level, from what I read.


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Re: Fertilizer dry mass percent?

Post by MorpheusPA » December 2nd, 2021, 11:54 am

Feather meal is usually just cooked in steam, then dried thoroughly (to 8% moisture or below) and stored. Apparently a feather is about 82% low-digestible crude protein (keratins) before hydrolysis and highly digestible (and apparently rather tasty) afterwards. The hydrolization process breaks the disuphide bonds. These are then used as food additives for ruminants, fertilizer sources, and so on. Source: Poultry World.

Dry mass doesn't necessarily mean no water, just minimal water. Dry hydrolyzed feather mass has, apparently, about 8% bound water. Dry soap? It's made with 20-38% water, but cures to 8% water, plus or minus a lot--chemically bound, and bound into the crystal lattice. Dry iron sulfate is 18% to 30% bound water. Water is attracted to almost everything--urea being a famous humectant.

So I think I'm not quite understanding the question. The fertilizer's meeting the set standards (which will include those for moisture) when it gets tested for nitrogen. If it should get a little damp after that, sure, it can impact the N ratio by weight, but the overall N weight in the bag, grand total, should be stable assuming there's no bacterial processing going on (urea flipping form without bacterial assistance is pretty minor, so we can ignore that). Time, treatment by the consumer, and opening the bag will all have an impact, and that has to be accounted for, of course.

For grains, they don't list an NPK on the bag (mine comes in a plain brown bag reading "soybean meal" with a crude protein guarantee and that's it). So moisture doesn't come into play there, and sure, sometimes I get a bag that's a tad cakey. For my purposes, it really doesn't make much difference.

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Re: Fertilizer dry mass percent?

Post by Green » December 2nd, 2021, 8:29 pm

My question was this: how are the differing "slowly available N" and "dry mass from organics" reconciled when they are drastically different? And why the discrepancy?

You can see it in the above example. But here is another example, from a bag of fertilizer in my possession that I'm going to test out next year:

*Total Nitrogen (N).........................16%
----15% Ammoniacal Nitrogen
----0.8% Water Insoluble Nitrogen

*4.8% Slowly Available Nitrogen from protein hydrolysate, water insoluble nitrogen

16% of the fertilizer dry mass comprised of Protein Hydrolysate
-----------

4.8% is not 16%...I'm confused how 16% of the fertilizer dry mass can be from the organic source of only 4.8% of the N (30% of the total) is from those slowly available sources.

Additionally, I don't get why the water soluble 4% (4.8 - 0.8) from organics is labeled as part of the 15% Ammoniacal N, either. All I can conjecture is that a.) Proteins contain N, and b.) This particular fertilizer is made by combining the raw organics with aqueous Ammonia such that it's homogeneous, so they can call everything except the WIN fraction Ammoniacal. (I'm currently reading through the patent.)

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Re: Fertilizer dry mass percent?

Post by MorpheusPA » December 3rd, 2021, 12:44 pm

Gotcha. Yeah, in most cases, we use the "average" (good luck with that!) protein and divide the crude protein mass by 6.25. So soy's 44-49% proteins result in around 7% nitrogen levels. Availability varies, but most of it's moderate.

In this case, it seems that 16% of the average "dry" mass of the fertilizer is made of protein hydrolysate.

The protein hydrolysate itself looks to be 33% nitrogen by weight, which is fantastically high. Those bonds must not be so much broken as shattered, and fairly easily available.

Proteins do contain nitrogen, that's actually why we apply copious grains to our lawns and gardens. Divide the protein content of grains by 6.25 to determine nitrogen content percentage, like the soy example above. About half of the nitrogen supply in the gardens and three-quarters of the nitrogen supply to my lawn is organically (protein) sourced.

However, the ammonia listed isn't aqueous, it's in urea form (I'm presuming), or two ammonia ions bound to a carboxyl base. If not, I'm thinking ammonium sulfate or another soluble ammonium salt form. Insoluble forms are certainly possible and wouldn't surprise me, but I'd think they'd control the process to limit those. Even so, there's gonna be a bacteria that likes those.

Urea has to undergo hydrolysis in the soil to turn into two ammonia molecules (bacteria do that for us). In this case, there seems to be a side effect from the process (I'm guessing) that results in the production of urea. Rather than remove it (why bother?), they simply include it with the rest and ship it off. For soluble ammonia salts, they simply dissolve and the ammonium ion is available. The anion is also available for plant usage, so it's wise to assure that the one supplied is useful...

MIlorganite works the same way. Part of the N in the process is soluble (about 40%).

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Re: Fertilizer dry mass percent?

Post by Green » December 3rd, 2021, 2:41 pm

Hey Morph,

I don't think there is any urea in the most recent example. It would be listed as such. Plus, the maker uses Aqueous Ammonia in the processing (specifically stated--versus anhydrous--because it is easier to transport aqueous material or safer to handle or something). They state that this creates both ammonium sulfate and ammonium phosphate in the final product. Also, the ammoniums apparently get complexed with the organics, resulting in a slow release delivery. They claim that the majority (16 - 4.8% = 11.2% of the N is available over 2-3 weeks. If it were not complexed, ammonium fertilizer would be immediately available...no? And the rest is slowly available over about 6 weeks. So, this complex sounds similar to chelation to me. The product smells like animal feed without even opening the bag...very strong "organic" smell.

How did you get the 33% number?

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Re: Fertilizer dry mass percent?

Post by MorpheusPA » December 3rd, 2021, 9:51 pm

Green wrote:
December 3rd, 2021, 2:41 pm
I don't think there is any urea in the most recent example. It would be listed as such. Plus, the maker uses Aqueous Ammonia in the processing (specifically stated--versus anhydrous--because it is easier to transport aqueous material or safer to handle or something).
There's a great (for disgusting definitions of great) video of a truck of anhydrous ammonia having an accident out there. The driver is caught in the vapor, collapses, and a trooper catches this on camera as he stops to help. Without investigating the truck, he rushes into the cloud of vapor to help...and collapses. Both died in seconds.

We used this at a previous company as a training video to ALWAYS READ THE FECKING DANGER MARKINGS BEFORE YOU GO INTO A GAS CLOUD OR POOL OF LIQUID.

Yes, aqueous ammonia is much safer and easier to handle than anhydrous. This video is on the Internet. I will not link to it as it shows two men dying. Instead, enjoy https://www.youtube.com/watch?v=IAHzP4umE4M Staplerfahrer Klaus (Forklift Driver Klaus), with English subtitles. It's a hoot.
They state that this creates both ammonium sulfate and ammonium phosphate in the final product. Also, the ammoniums apparently get complexed with the organics, resulting in a slow release delivery.
Sensible. Ammonium sulfate and ammonium phosphate will be fast release, and the sulfate will provide sulfur while the phosphate some phosphorus. Ammonia will happily adhere to any negatively charged site on an organic.
They claim that the majority (16 - 4.8% = 11.2% of the N is available over 2-3 weeks. If it were not complexed, ammonium fertilizer would be immediately available...no?
Variable. Ammonia salts are available the instant they dissolve. The untutored say that urea is immediately available and plants can use a tiny percentage of urea as-is, but it actually does require hydrolysis via bacterial action (natural hydrolysis in water happens, but takes a thousand times longer). That takes time. Figure 3 days, on average, but that's going to vary. A lot, with 3 being the floor number. Very bacteria poor soils, such as nearly pure sand, would take much longer until populations build (which they will rapidly do when the urea is available).

Temperature actually isn't much of a limiter, with any reasonable temperature regime not really impacting availability all that much. A few days, sure.
And the rest is slowly available over about 6 weeks. So, this complex sounds similar to chelation to me. The product smells like animal feed without even opening the bag...very strong "organic" smell.
Yes, it does, and it's an interesting concept. Basically, pour ammonia on compost. Grind to fertilizer. Compress into pellets. Use. In theory, there's nothing wrong with the idea. Organics happily bind positively charged ions quite easily, releasing them as they decay. The bacteria would be more than happy to suck up the ammonium and flick nitrogen forms around indefinitely, handling the nitrogen processing for us and trading it to the plant roots.

The question becomes price; soybean meal is quite cheap for me ($15 for fifty pounds, or about $4.20 per pound of nitrogen). Plus I get the excess, non-processable organics as a soil conditioner (which this would, necessarily, have far less of).
How did you get the 33% number?
If 16% of the mass is protein hydrolysate and 4.8% N is WIN from this, then 4.8 (bag N)/16 (bag % weight) = 0.3 = about a third, or 33% of the mass of protein hydrolysate is nitrogen. As I reconsider this number, it's ridiculously high; no organic has an EC that high. There's more to this story than simply binding ammonium to an organic.

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Re: Fertilizer dry mass percent?

Post by Green » December 4th, 2021, 1:50 am

Morph,

Let's answer the cost question first. Yes, this particular fertilizer we are currently discussing is more expensive than your SBM. I saw it advertised two years ago for $5.10 per lb of N at certain Agway stores, but that was two years ago and I don't have a local store that sells it (though it won't hurt to ask my local stores if they might consider it). That's pretty competitive. The bag I got had to be ordered, so shipping pushed it up into the $8 per lb of N range. Still competitive with Milorganite bought locally, though, which is in the $7 per lb of N range here. But each product really has its own profile, this one having far less P than Milorganite per lb of N. So I don't consider them totally interchangeable and might actually combine them into a single app. Guess I'm a bit of a fertilizer conissieur (or snob, pick your descriptor).

I think I follow your calculation. But the WIN portion was 0.8%, if that's what you wanted to base it on. You based it on 4.8 (the total slow release percentage).

I will delve more into the processing and we can try to understand it better.

However, before we go further: why do you think the organic portion (the 4.80% from hydrolyzed protein matter) was included as part of the Ammoniacal N on the label? Is it because proteins have amino acids? Or due to the complex that results from processing with Ammonia?

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Re: Fertilizer dry mass percent?

Post by MorpheusPA » December 4th, 2021, 12:32 pm

That's actually pretty reasonable as a price, so if it were locally available, I'd consider it as an October feeding where it would be in the ballpark for use. I generally boost it with Milo that month for the added iron.

If WIN is 0.8 (I was using total N in the organic), then the bound portion is 0.8/16 = 5%. That's still rather high, but more reasonable.
However, before we go further: why do you think the organic portion (the 4.80% from hydrolyzed protein matter) was included as part of the Ammoniacal N on the label? Is it because proteins have amino acids? Or due to the complex that results from processing with Ammonia?
I couldn't say, but at a guess, it very well may be because it's fast release and reduced to an ammonia salt. So more the latter than the former; amino acids bound into proteins are very much slow release nitrogen. Without knowing the exact process, it's pretty opaque and a magic box to me right now.

The more I consider all this, the more I'm not all that zinged by the fertilizer all things considered. It's OK. There's nothing wrong with it. Overall it's not a problem.

But when you combine the higher price compared to soy, the limited slow release, and the curves I'm seeing (mostly tilted sharply toward 0-3 weeks), with seemingly very little in the way of soil conditioning capability, all things considered and on balance, if the choice were between soy and this, I'd choose soy.

For a transitional product, it's nice. Where grains aren't available, it's great. But where the choices are wider, let's go with a grain and let the bacteria do the processing.

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Re: Fertilizer dry mass percent?

Post by Green » December 4th, 2021, 3:43 pm

So, I've actually never used grain fertilizers. Partially due to lack of availability in my area, but also because I won't handle unprocessed soy fertilizer due to a sensitivity. I also have always bern attracted to the idea of commercially processed organics, which I call high-efficiency organics. I've been using such products as a major part of my program for all these years since joining here. While the exact products have differed over the years due to availability, the core concept remains the same. Milorganite has been the only one I've used consistently, all these years due to availability. I tend to mix and match slower and faster release organics based on time of year, goals, etc.

One of my favorite such products that I've been using for several years has the following analysis for N:

Total N: 8%
--Soluble: 0.6%
--WIN: 7.4%*

*7.4% slowly available N from protein hydrolysate.

It feeds for a very long duration. It also has a 2:1 N:K ratio and a near-zero P level, perfect for my soil. The K source is Sunflower hull ash, which I find intriguing when it comes to sustainability.

The ingredients are: protein hydrolysate, feather meal, sunflower seed hull ash, and molasses.

This reminds me to ask you: are fertilizer ingredients listed in order of quantity?

Also, any comments on the technology? This one likely uses a slightly different processing. From the SDS: "If heated to decomposition, will give off toxic fumes from ammonia." I find that interesting, even though no ammoniacal N is explicitly listed. Thoughts?

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Re: Fertilizer dry mass percent?

Post by MorpheusPA » December 5th, 2021, 8:16 pm

Yeah, some people are certainly allergic to soy. Milo's certainly comparable and sustainable since people are going to poo. :-) I'm fortunate; no allergies of significance. Many allergies that annoy me, though. I have to say, that Roomba? Best thing we ever bought. My allergies are cut down by two-thirds in a week.

Milo has a higher P level, of course, so perhaps not for every month use...

Fert ingredients are by NPK, then internally in the N by Soluble, Insoluble (then chemically insoluble and WIN, respectively). At least that I've ever noted. As to whether that's a law, or just convention, I'm not at all sure.
Also, any comments on the technology? This one likely uses a slightly different processing. From the SDS: "If heated to decomposition, will give off toxic fumes from ammonia." I find that interesting, even though no ammoniacal N is explicitly listed. Thoughts?
The keywords here are, "Heated to decomposition." I'll guess that decomp is at fairly high temperatures, where the nitrogen is just grabbing hydrogen from internal sources and running with it. Or, don't set it on fire. I've over-run a compost bin so hard that it was pouring out ammoniacal nitrogen. It. Was. Awful.

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