My friend got a load of old powdered horse and cow manure from inside a big barn (dry inside ). This was not composted ! This stuff is dry like dust and pulverized. My question is what is the value of this manure versus some that has been composted . Will the uncomposted manure just take longer for the plants to utilize it ? It has not been leached out because of being inside also because of the lack of moisture there is another factor unknown. smith

Probably full of hay and weed seeds from the horses

It will have a lot of seeds as stated but as to nutrient contents? Because it is very powdery that means the particles are small and thus when moistened and the right temps are reached it will dissolve quite easily and quckly.
As to value? Just because it was inside does not mean a lot of the nutrients could be lost. Most of the N is in the urine and if the urine is all evaporated away a lot of N is gone as well as some of the K. It won't hurt your garden, but there needs to be N in the humus you have as it takes N to break down organic matter so before manure and other OM can contribute it uses N and other nutrients. In most cases thouogh the manure gives back more than it uses. That is why many farmers use a small amount of starter fertilizer and even on fiields of 1st year corn after legumes with manure because the soil needs to reach certain temps to break down OM and the other bugs that help do that. In organic fertilizer can give the seeds and plants a better start. One of the reasons many organic growers plant later is to use the warmer soil temps to have more nutrients quicker for the seeds and plants.

Bryce

Should still work well for your garden. I want to second Bryce's post as well.

We use indoor Manure all the time. We built a Concrete Pad and then walls and a Roof just to keep it in because it is easier to use a Bobcat to load it. We sell what we do not use. It is Horse Manure and sits about a year before emptying it. The Back of the stuff is like Powder and it is good Fertilizer. It tills in better also.

The heat of the compost pile kills the weed and grass seeds in the anaerobic cycles. I would compost it before using it in my vegetable garden.

Thanks to all ! Bryce that is helpful info .You must have some formal schooling on the subject and I appreciate the time you took to share it . My friend that is to use it has little experience in farm or garden and he is afraid to mess up his potatoes . I did not know that the N in urine would evaporate ! If I had more livestock now I would build something like randall has . It is so cold here in winter I would need a big deep pile .I am never too concerned about the weeds in my own pile Kevin .Edp the stuff I have on my place will go in a small patch of oats for hay or grain . Thanks to all smith

Manure is one of my favorite subjects (being an organic farmer and all). Already some very good information posted by Bryce and others. As Bryce mentioned, even if the manure isn't being leached by the rains the material may lose much of its N as ammonia into the air. The value of composting is it tends to fix a percentage of the N into slow release forms. As well as heating up enough to kill weed seed and pathogens if done right. Your pile needs to have sustained temperatures of around 130-140F to accomplish that.

One other point to mention is it depends greatly on how much bedding material (and what the bedding material was) as well as to what the diet of the manure producing livestock was as to how much starting N was in there.. Good protein in- good N out.

Expect that on average cow and horse manure will be somewhere plus or minus 1% N

One more concern I might add to the use of dried manure is the salt content may be higher than some plants like. Continued use of animal manures is known to reduce blueberry yields.

beaverpeeler that is good to know .Last week things are springing up here at last .I was visiting a friend who is an outfitter in the backcountry and he has 30 head of horses to winter on his feed ground and you could not see the ground for the manure on about 10 acres of his place .He buys all his hay so in essence he is importing some fertility . It would be enlightening to see the results of a soil test on that place ! Another place the owner has to winter 150 head of cows on a sandy ridge ,he grows some fine irrigated barley on that piece with the manure from the winter feeding and all he has to do is harrow it in and seed the barley

I wouldn’t use it for a garden but I’ve used similar for canine set cover instead of dirt they don’t shy away from it and it does repel water quite well like peat does