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Fresno, Ca

Need help analyzing some commercial compost. Mostly to make sure the levels aren't out of whack... toxic. I know these questions come up quite often, it would be nice if someone wrote an article that gave max/min levels and things to watch out for. Thanks in advance for your help

Dry Wt. Basis

Total N 1.5%
Ammonia 5 mg/kg
Nitrate 128 mg/kg
Organic N 1.4%
Phosphorus (P2O5) .51%
Phosphorus (P) 2233 mg/kg
Potassium (K2O) 5.6%
Calcium (Ca) 2.0%
Magnesium (Mg) .52%
Sulfate (SO4) 43044 mg/kg
Copper (Cu) 36 mg/kg
Zinc (Zn) 109 mg/kg
Iron (Fe) 6734 mg/kg
Manganese (Mn) 193 mg/kg
Boron (B) 21 mg/kg
Sodium (Na) .1 %
Chloride (Cl) .13 %
pH 7.28 (wet wt. basis)
Carbonates (CaCO3) 12 lb/ton
Organic Matter 36.3 %
Organic Carbon 17.9 %
Ash 63.7 %
C/N Ratio 12

4/7/2008 9:26:07 PM

southwest MO

You have done a great job relating the information... But I dont see the first thing I look for when evaluating a compost result... Salts-- or Connductivity... I instantly become suspicious when all the other analysis are laided out so nice and neat and connductivity is missing...

Most of these #'s look typical... SO4 is over 4% if you posted correctly. That seems high

Lots of folks who dont look at #'s like these every day are shocked to see them so high... Rememer these are Total #'s not availiable #'s.

Try and get us a salt level.

4/8/2008 10:02:11 AM

Fresno, Ca

Wouldn't salts fall under Sodium and Chloride? I left off Electrical Conductivity, 12.259 Wet basis and 22.40 dry basis. I'm not too concerned about salts because this is all plant matter compost(no manure) city green waste and winery grape pumice. Appreciate your help!

4/8/2008 6:35:23 PM

Fresno, Ca

The sodium and chloride are listed under the Salts, category don't know if that helps either.

4/8/2008 6:36:46 PM

Phoenix, AZ

Salts are negative ions: nitrates, sulfates, chlorides. Don't confuse the everyday "table salt" with your analysis.

Put that stuff on the soil and water and the salts magically go away...well not magically but salts are the least of your problems.

4/8/2008 11:59:28 PM

southwest MO

Salts are the first line indicators of the maturity of the compost. Often times when this sort of compost is made it is pushed out the door as soon as possible as there are storage problems with large volumes... In my opinion this compost is immature and has not finished cycling. Finished compost should have salt levels well under 6 mmohms. Organic matter should be over 50%. If you let it sit these things will happen.

Salts are not negative ions. They are a combination of negative and positive ions to form a nuetral compound called a salt. This forms a bridge on witch a electrical current can pass and then is measured.
I dont think speedguy was after a "put that stuff on you soil" answer. He would have not been so technical in his post...
I would love to hear others opinions on the above analysis as Im sure speedguy would to.

4/9/2008 10:17:57 AM

Fresno, Ca

Appreciate the clarification, wasn't quite sure what the put that stuff in your soil comment was about anyhow. Maybe the best bet would be to mix this compost in with some that I have already made at home and continue to compost it?

4/9/2008 11:58:41 AM

southwest MO

If it where going in my dirt I would use it sparingly this close to planting time. The closer we get the less I would use. I certianly would not bury or mulch vines with it.
If you have the room- pile a bunch of it up now, let it sit till the fall, work it in then, and grow in it in the spring.
I have gotten many loads of "municiple compost" and it is always still very warm or even steaming if its cool out side. It also frequently smells a bit anerobic.

There is certian procedures that have to be followed and such. Mainly they have to get the material over a certian tempature like 131 F for x amount of days. These folks have no trouble doing this at all. They can really man handle it and get if off to a rippin start. The problem is these giant piles are still very active for long periods of time. Yes they meet the criteria for vector reduction and E. coli limits after only 3 weeks but it may take many months for these hundred+ yard rows to completly cure.

4/9/2008 1:47:21 PM

Decatur, IL

Your C/N ratio (12) is low enough for finished compost. As a general rule, you want it below 20 so that you don't have a problem with nitrogen being tied up and not being available to the plants. If it's below 20, I'd consider it mature compost.

4/9/2008 5:36:57 PM

Fresno, Ca

"Smells anerobic"? What exactly does anerobic smell like? My pile at home can get fairly strong smelling like ammonia especially with too many grass clippings, and not enough leaves. Otherwise it smells somewhat earthy/musty There piles definitely smell but I always assumed it was the quantities they are producing.

4/9/2008 10:22:07 PM

southwest MO

C/N ratio on a finished product is useful only if you know the begining C/N ratio. I agree its a good ratio but not the best indicator of maturity.

4/10/2008 10:08:15 AM

Decatur, IL

Start some radish seeds in it. Also start some radish seeds in regular seed starting mix. If the seeds sprout equally well in each, then there probably isn't anything phytotoxic in your compost. Also, if it smells "earthy" or has little or no odor then it's probably fine. If it has a foul or ammonia odor, don't use it.

4/10/2008 11:00:12 AM