sawdust and horse manure.

[anne1953]

I have access to stable manure and urine soaked sawdust. I know the horse manure is safe to add to compost but I am worried that the sawdust will alter the ph balance in the soil. I plan to leave the mixture to rot over winter.

[RamonaGS]

Ok, my friend grossed me out with this article about human pee-cycling, but I think it can answer your question about the urine soaked sawdust, and it's safety in your compost.

https://www.nwedible.com/2013/03/how-to- ... arden.html

[tomc]

Very rarely does the acidity of an organic material remain after composting.

In the case of urine soaked sawdust, its capacity to harm plants has more to do with the urea in it heating up.

That big steaming pile of barn sweepings, will when composted be a much smaller pile of more stable-ly available fertilizer. Its PH will be about neutral.

[rainbowgardener]

Sawdust directly incorporated in to your soil could cause problems, locking up Nitrogen, changing pH, etc. Sawdust in your compost pile, mixed with manure, kitchen scraps, pulled weeds, etc and preferably not accounting for much more than 10% of the volume of the pile, becomes COMPOST, pH neutral and pretty indistinguishable from any other compost.

[toxcrusadr]

Sawdust is a 'super brown' with very very low N content, so it needs a lot of nitrogen rich material to go with it. I've made tons of very nice compost with sawdust and wood shavings, grass clippings, food waste and garden trimmings.

[RamonaGS]

Sawdust is a 'super brown' with very very low N content, so it needs a lot of nitrogen rich material to go with it. I've made tons of very nice compost with sawdust and wood shavings, grass clippings, food waste and garden trimmings.

Wouldn't the horse manure, and urine be Ni rich?

[toxcrusadr]

Absolutely! Depending on the ratio, it may very well compost down quite nicely. If it doesn't, and you see a lot of sawdust that is still recognizable, it might need more nitrogen. Add depends on what you get from the stable.

OH, one more important thing! Ask the stable if they use any lime for odor control. Sometimes very strong hydrated lime (not the ground limestone you normally get in a bag) is used in barns and stables, and the pH of the manure/bedding mix can be very high. Always good to know that.

[RamonaGS]

Good to know Toxic Crusader, I was not aware of any use of lime, but also I am not using anything from stables to add to my compost, and have not been around horses much. Dogs, cats, chickens, ducks, and occasionally goats, but horses...not so much, lol So how is it lime would change the chemical profile from the type of lime from the hardware store?

[toxcrusadr]

Regular ag lime is ground limestone, calcium carbonate, CaCO3. Or if you get dolomitic limestone, it's magnesium carbonate. It has a natural pH of about 8.3, about like baking soda, so that's about as high as it can drive your soil to if you use a lot of it.

If you roast it in an oven, it becomes calcium oxide, CaO, which is a very strong base. It's then 'slaked' with water to make calcium hydroxide, CaOH2, aka hydrated lime. This stuff has a pH way north of 8.3, more like 12. It's powerful stuff. Since it takes a lot less of it, it can be more efficient if you're treating large fields.

If a farmer uses hydrated lime in the barn for odor control, the manure/bedding can come out with a very high pH. Since it's a mineral base (rather than organic or vegetative) it does not compost away. It's longer-acting and can take time and effort to correct. Now and then someone posts on one of these forums with pH problems that are traced back to barn cleanings. So it's always good to check with the manure supplier. The chance is fairly small but something to watch out for.

Next week we'll go into persistent herbicides used on hay fields showing up in manure which then kills people's gardens...but I don't want overdo all at once.

[Dillbert]

>>but I don't want overdo all at once

and the wormicides . . .

[RamonaGS]

Ah so it's not just lime but super lime. I have not used manure or barn waste in my compost, but never know. Good information to have in the future just in case, lol

[tomc]

Sawdust directly incorporated in to your soil could cause problems, locking up Nitrogen, changing pH, etc.

How exactly would urine soaked saw dust tie up nitrogen?

Inasmuch as wood breaks down by action with mycoriza and the nitrogen used is taken up by those mushroom families.

[RamonaGS]

Sawdust directly incorporated in to your soil could cause problems, locking up Nitrogen, changing pH, etc.

How exactly would urine soaked saw dust tie up nitrogen?

Inasmuch as wood breaks down by action with mycoriza and the nitrogen used is taken up by those mushroom families.

So as a new composter...would sawdust, urine, and manure make compost too rich in nitrogen, nitrogen poor, exactly balanced? Would the sawdust and urine be in balance? When you all talk about a substance being "tied up" does that mean it is in there, but has low bio availability, or is it in there and ready to be absorbed?

[cynthia_h]

I have access to stable manure and urine soaked sawdust. I know the horse manure is safe to add to compost but I am worried that the sawdust will alter the ph balance in the soil. I plan to leave the mixture to rot over winter.

Just so we remember the OP's question....

The topic of nitrogen lock-up has been discussed in minute detail in Teaming with Microbes (rev. ed.), which the forum did as a group read-along in 2011, esp. in Chapters 5 and 19, which address fungi and mycorrhizal fungi. Suffice it to say (without dragging this thread off-topic) that the nitrogen is "busy" degrading/decomposing the wood--a carbon-rich substance--and is thus not available to plants. Once the wood is degraded/decomposed, any remaining or supplied nitrogen will then be available to feed plant roots.

Amazing book; I've got to get back to it. Again....

Cynthia H.
Sunset Zone 17, USDA Zone 9

[RamonaGS]

I'll have to look for that book Cynthia. It sounds very helpful. I just got an Amazon gift card too!

[toxcrusadr]

would sawdust, urine, and manure make compost too rich in nitrogen, nitrogen poor, exactly balanced? Would the sawdust and urine be in balance?

It all depends on the ratio of the ingredients - how much sawdust in relation to the high N manure and urine. If I made you a hot fudge sundae, would it have too much hot fudge for you, not enough, or just right? It all depends.

[rainbowgardener]

same applies to " How exactly would urine soaked saw dust tie up nitrogen?" Sawdust (plain) incorporated in to the soil, will tie up a lot of nitrogen. Urine soaked saw dust maybe not, if there was enough urine to provide enough N to do the decomposition of the sawdust, which as tox has said is a "super-brown." Depends on the balance.

[RamonaGS]

If I made you a hot fudge sundae, would it have too much hot fudge for you, not enough, or just right? It all depends.

Terrible example Toxic! There can never be too much hot fudge on a sundae for me! I'd eat hot fudge right out of the jar!!! NOW....Who's gonna make me a sundae?! Come on...who's my buddy???