The organics forum for "...the discussion of organic gardening. Organic gardening is most easily defined as a philosophy that stresses the use of naturally occurring substances and friendly predators and avoiding man-made chemical fertilizers and pesticides." is over here.

This forum is for the discussion of all aspects of soil.

I use herbicides as well, sometimes it is necessary under certain conditions.

Lloyd

We have no idea what your spoil is like, so can't offer advice that is meaningful. Try tilling them in and see how the plants react. IF they show signs of nitrogen deficiency, it's easy enough to correct with a bit of ammonium sulfate.

The ability of wood chips to sequester nitrogen is overestimated.

The carbon to nitrogen ratio could be calculated and an answer could be offered, but then there would be the issue of rate of decomposition of the wood chips and loss of nitrogen prior to it being used. For example, wood chips that come from a tree service wood chipper would be relatively large in size. The outer surface of the wood chip would be ready for decomposition and would use some of the nitrogen, but the inner volume of the wood chip's carbon would not be available until the outer surface was decomposed. If you had provided all of the calculated nitrogen at the beginning of the decomposition process, much of it would be gone before the chip was fully decomposed.

Short answer would be to throw some alfalfa pellets onto the large pile of chips and let the chips get started decomposing. Then spread them on the soil. Keep the chips damp. Don't till them into the soil too deep. As mentioned, we have observed that wood chips seem to decompose much faster when used as a mulch instead of as a soil amendment. Eventually they become a soil amendment, but they rot faster when left on the surface.

I have a chipper/shredder and have observed that green branch tips, when chipped, start decomposing so rapidly that they heat up to over 140 degrees and dry themselves out. My chipper probably chips the branches into much smaller chips than you'd get from a tree service, but I still suspect that your fresh chippings would also heat up from decomposition. Keep them damp and they'll get a good start at decomposition without the use of Urea or other nitrogen sources.

So a search on 'ramial' in this soil forum and you'll find more discussion of the subject of fresh wood chips.

californian are you sure you want to till the wood chips in. They can be a pia for a few years. I would think mulching would be a better use for them. As far as urea I do not have a clue. I like lazygardens idea best. I also am not totally organic. Heck I have even used MG and the world still turns. I had to use Seven last year, but do not like to.

Curt :-)

Hmmm.... SOILS AND COMPOST are under the main heading of the link you provide to ORGANIC GARDENING. Sorry if I stepped on anyone's toes. I didn't mean to shut off any discussion of ANY aspect of soil cuture. Just expressed my opinion within what I thought was the context of this OG forum - "creating a healthy balanced soil".

BTW - Lloyd .. do I have you mixed up with another person who frequently adds as a PS to his comments that he doesn't garden? A distinction between farming and gardening maybe in the use of herbacides, etc.?

I don't want to butt heads over this ... or pick an argument with you .... I admire your viewpoints on composting as well as your occasional irreverent humor.
And EEEEK! don't want to be on the sharp end of your sometimes barbed wit!

Yup, I'm the non-gardener. I have gardened, just not so much since DW became disabled. But I have no issue with using 'cides for what they are designed and allowed for whether in the garden or field.

The soils and compost is under the "related forums" over there just like "organic gardening" is a related forum over here. Just thought you'd get more "organics only" 'stuff' over there as opposed to here if that is what you were looking for. I didn't intend my comment to be a 'disagreement' and I apologize if it came out that way.

And I think you may have had a typo with "your sometimes barbed wit" when you might have meant "you're sometimes a twit". :-)

I like humour (irreverant or otherwise) and I'm sure sometimes a lot of people don't get my humour but I also try to call a spade a spade and will challenge when I think something is incorrect.

I add some of the P.S.'s to make sure that people understand I am not an expert and the grain of salt thingy ought to be considered with some of my opinions.

Lloyd

P.S. Sorry to the OP for going off track here (again).

If I had access to those chips I would pile them up in a windrow, add plenty of coffee grounds and green stuff, and then add urea as needed to get them heating if you want to use urea. Personally, I think I would try it with other greens, as I think they would bring more life to the party, and aid in preserving moisture in the pile. I don't think it is necessarily a bad thing to pay the man for his fuel, after all, he has already chipped them up for you(no small expense on his part). I think it will take a while to compost those, but hey, I don't have the experience to tell you how long it will take. If you lack patience, you might just be better off without them, but I'd surely give it a shot. I do almost all my composting in a worm bin, and seldom compost anything harder than cardboard, but if I had access to wood chips, I think I would make use of them in some way. steve

Well I don't think its a bad deal to pay for the fuel to get the chips there as long as its reasonable

I don't think there is a sure anser for the question at hand though I would load it up with alfalfa pellets as you till for slow release and then add nitrogen fertilizer as you see fit

Also not everybody has but my tree guy has a pile at home that has been composting for years and they work super as an soil ammendment

Tilling in an amendment that's tough to break down and has an unknown portion of softwood chips, needles etc., with their high resin and lignin content, then adding petroleum-sourced nitrogen to the mix - I don't see this as doing yourself, your soil organisms, or whatever you're planning to grow this year, a favour.

I love tree trimmings, though. We can never get enough. We've used about a dozen truckloads to mulch the wide paths between berry rows. The softwood trimmings are the best for discouraging weeds, and break down into the kind of fungusy mulch brambles like.

Lemme take a crack at this: assume woodchips are all carbon (no N) and urea is 1/2 nitrogen. To get a 30:1 C:N ratio we want a 15:1 ratio of wood chips to urea (by weight).

Now suppose you mixed together 100 lbs of urea and 1500 lbs of wood chips and wetted it all down, you'd have one heck of an ammonia smell for a couple of weeks, 'cause urea nitrogen would pretty much all volatilize or leach out in a month or so. Your pile would be VERY nitrogen-heavy for a month and then revert to just carbon. You don't want those kinds of nutrient swings in your garden, believe me.

The question is how quickly the wood chips can use the nitrogen. Let's assume, they can decompose in three years given the ideal N:C ratio. So (assuming year-round temps above 40F or so) you want to add 1/36th of that urea each month, or about 2.5 lbs of urea for each 1500 lbs of woodchips every month. So, to the extent that we believe the original 3 year figure and year-round composting, that would be the ballpark number to keep the nutrients balanced.

I'll tell you what I do, though: take 4 pallets, make a bin, and fill it with wood chips. Wet down the chips as best as you can. Dissolve about a quart of urea in 5 gals of hot water and pour into the woodchip pile. This will kick it off to 150F or so for 2-4 weeks. When the pile cools back down, turn it over - if not ready, add another quart of dissolved urea and repeat until you're happy with the consistency of your compost. It takes me 3-4 'urea waterings' before the stuff looks reasonable, and I'm ready to till it in.

I received 2 large loads from a local trimmer last fall. One pile heated up on its own (green chips), and when I moved and spread it this week It had broken down substantially. I used it in pathways and as mulch.

More than likely, even with a clay soil, there would be no need to till those wood chips in. Simply putting them on the soil and then allowing the Soil Food Web to work on them for you, and they will move those wood chips into your soil over time, would be far better and that would not require spending money on Urea or any other "fertilizer.
However, with a C:N ratio of around 500 to 1, depending on the age of the chips and the quantity of chips you tilled in per square foot, and at a ratio of 1 part N to 3 parts C you would need about 2 pounds of N per square foot of soil and more if more than a couple of inches of wood chips were to be plunked down and tilled in. That would be 5 pounds of Urea per square foot.

If you get the chips from a tree trimmer, they usually also have a lot of leaves and twigs, which are fairly high N2.

I use anything I run through my chipper as mulch and nothing has died yet.

Many years ago, I filled the benches in my greenhouse with sawdust to embed pots in it. Soon, all sorts of creepy looking animal life started crawling through it. I disposed of that sawdust by mixing a ~6" deep layer with the soil in front of the greenhouse. Nothing would grow there for the first year, but after three, it was the best soil in my yard.

I think there was more than nitrogen depletion inhibiting plant growth. I think that foliar feeding N to the plants in the sawdust amended soil was ineffective but I don't remember exactly.

Check out the North Dakota method for amounts of nitrogen fertilizer needed for compost

http://www.fao.org/docs/eims/upload/230151/On_farm_comp_methods.pdf

It probably gets the C:N ratio where it should be for finished compost but I think I ended up using only about 5 lbs per cubic yard (half a bag of lawn fertilizer) to get my chips into a usable rough compost to add to my clay, and then I fertilized the garden in the normal way (20:20:20 granular fertilizer).

I had great luck turning clay soil into rich garden soil using urea ammended wood chips, but I composted the wood chips first, adding urea at each turning. In summer the piles would dry out and cool down after about three weeks so I would turn them wet and add more urea. The first time I did this I used December chipped wood ammended with urea and composted under the snow the next spring (May) for a new clay soil garden by putting down a 5-6 inch layer of the young compost and mixing it in to the top ten inches of clay using only a shovel. So,I would suggest at least partially composting the woodchips first (six months to one year) to create an environment conducive to microbial growth and incorporation and transformation of the nitrogen into an organic form. This process would take much longer (years vs months) if you just mixed the chips clay and urea in-ground, and result in a loss of alot of the nitrogen through leaching. I also think that the chunks in unfinished compost (vs fine finished compost) help separate clay clods and the fungal growth acting on the partial compost once it is in the soil will really help on the microstructural level.

I disagree that soil life will turn under wood chips in clay soil. It just does not happen here.

If you mix wood chip compost in with clay soil roots get nutrients from the compost and then grow into the clay clods and help to break them appart the next time the soil is tilled.

Young/rough chip compost may be a bit nitrogen deficient in the soil the first year for some plants and you may need to add more nitrogen. In first year rough soil aggressive rooted plants like tomatoes grew better than things like onions. If I were not in a hurry for a summer crop I would sow a densely rooted cover crop like winter rye in with the compost/clay. By the second year my original yellow clay looked like dark brown potting mix when turned over. Rain does resuspend the clay so the surface will always look like the original clay, and may even cause surface puddles, but the root zone below will still be will be brown and crumbly.

Spiced Ham, how do you think the wood that falls in the wilderness gets digested?

After many years of graduate school followed by teaching university environmental science courses I'm pretty comfortable in my understanding of how wood in the forest gets digested, and my ability to interpret observations in the field. What we are talking about here are fresh wood chips coated in wet clay if they are dug directly into the clay soil. This will seal off a good proportion of the surface area of the wood to microbial action and microbial spread. If composted a bit first the situation will be reversed and the clay lumps can get coated in fine particulates and humics, and fungal threads will be able to grow around the clay in a more or less contiguous organic environment rather than be blocked by walls of clay plaster.

If you are refering to deep incorporation of organic matter down into the soil... if worms etc could break up clay through the addition of organic matter on the surface you would not see the fromation or persistance of the natural soil horizons we are dealing with (the clay fragipan in the B horizon). I would not have a clay problem because I have had grass growing on my lawn for 42 years since the house was built. This means not only 42 years of root penetration and worm activity on decaying roots, but also 42 years of grass clippings from a mulching mower. Still, there is a claypan nine inches below the surface. The yard is home to a good population of night crawlers. Sure the top nine inches is wonderfully mixed topsoil (due to worms and moles), but that doesn't do my tomatoes any good once that top nine inches dries out at the end of June and the clay blocks deep root penetration to subsurface water. Surrounding the yard is a secondary growth forest that is over thirty years old. Plenty of time for soil life to mix decaying organic material into the clay...it just hasn't happened. And here is what I have observed with brush piles sitting atop clay soil for 20 years (total decay of the brush)... a couple of inches of rich black compost over top of clay (the same with old manure piles). I have cut and developed garden plots out of both the yard and the wilderness areas. This includes deep digging down to 2-3 feet by hand to break up the clay and mix in organic matter so I am intimately aware of the soil structure, root pentration and wildlife penetration.

Worms do not live in the clay layer other than for a few permanent vertical burrows, and plants do not put roots down into the clay to a great extent.

In a forest, subsurface clay is broken up by penetration and decay of large woody tree roots (over centuries), not from branch and leaf litter. Invertebrate activity will mix surface material into the nooks and crannies left by decaying roots. Most tree roots are on the surface in the nutrient rich layer, with very few deep verticals, which is one reason it takes so long for deep rich soil to form.

Darwin's estimates of soil turnover by earthworms as so many tonnes of soil per acre per year (in an English cultivated and/or garden setting) seems impressive until you convert it to inches, which turns out to be something like 1/8 inch of soil brought to the surface each year, so over 8 years you could get an inch of soil covering your wood chips, but even this isn't going to happen in worm depauperate clay.

With spiced ham's further explanation, I like his suggestion: Compost it first for a full year and then do your thing with it. With respect to his profession, there are many others with similar backgrounds who are not so well versed in the biology of the soil.

What you are getting from the tree trimmer is sometimes called Ramial Chipped Wood. I might lay the chipped wood out and use it for mulch while it was composting rather than piling it in a pile, but you're going to have to keep it moist no matter where you put it. Sometimes it is easier to keep moist when piled up.

I've tried many ways to keep my pile moist and have finally settled on a misting type nozzle. Shower heads waste too much water. The mister water might put out a gallon of water per day. Some might drift away in a breeze, but if you leave it on 24/7, it will wet your pile through and through without making it soggy. The mister I use is the kind used to cool the air in the hot, dry desert. It is not one of the Toro misting nozzles used to water plants. It really throws off fine droplets that seem to evaporate quickly, but somehow everything underneath gets wet.

As to what to use to increase the "nitrogen," keep in mind that it is microbes that cause the decomposition of wood, and those microbes need their nitrogen in the form of food, not chemicals. Inasmuch as urea is a synthetic recreation of a natural molecule, it might be good as food for the microbes. I prefer to use true organic fertilizer made from grains to supply additional nitrogen. Thus I agree with those who suggested alfalfa pellets as a "nitrogen" source and disagree with those who suggested ammonium sulfate (a salt). In organic fertilizer the nitrogen is supplied in the form of protein, which contains nitrogen molecules but is a real food.

Regarding the nature of the Soils forum: we've all been there borderbarb. This forum just seems like it should be organic, but it really isn't. Your wording was, "This is a soil and compost forum ... with a general viewpoint in favor of protecting the life within our soils ... which is adversely affected by chemical fertilizers." . After years of reading this forum you are exactly correct that the "general viewpoint" is in favor or protecting life in the soil. It is just not the only viewpoint nor are other viewpoints rejected as they might be in other forums. So the OP has a valid soils question, this is the place to go for answers (such as they may be). At least he's not asking a question about roses on the Pecan forum.

Here is a link that might be useful: On Ramial Chipped Wood - then follow the links

I am struggling with this now. Urea is almost pure nitrogen how much is needed is a big question mark. None of the composter info is on point because it deals with such dilute forms of nitrogen.

Houz isn't the lively place Gardenweb was at the time this thread started but since it's back from the garve I'll offer comment for consideration by stragglers happening by. I constantly experiment and have found huglekulter smooths out mistakes and consistently yields crops proportionally larger for effort expended. A pile of limbs,leaves and grass with enough clay to fill voids grows everything I plant the first year then gets better each passing year. With 75% less water yields are 75% produced in prepared beds. If wood tied up as much N as commonly advertised these mounds should be baren at least 3 years. That's my two cents on wood tying N up.

they will deliver for free. I have about 100,000 pounds of arborist chips just this last season alone and it's all from one arborist company. it costs them money to get rid of them. How much Urea? One truck load (10yards) is some where between 8000 and 10,000 pounds. To decompose as rapidly as possible you will need a 55 pound bag of Urea. I also use 40 pounds of lime, 50 pounds of wood ash, and 30 pounds of plain white sugar. Keep the pile moist and use a dark tarp. Turn it, when it gets hot. You could just let to go and leave it as a static pile. What happens then is you get anerobic activity instead of aerobic composting and your pile may turn a bit smelly. It may take longer too. I am a fan of fungal composting so I turn my piles. Before you invite an arborist to bring you a load of chips figure out how you will move it and work it. 10yards of chips is a rather considerable amount. you will need a tractor or skidsteer to manipulate your pile.

Some clarification may be needed on this extremely old thread. First, wood chips applied as a mulch or topdressing will not impact soil nitrogen at all. Wood chips incorporated into the soil will not deplete the soil of nitrogen but only make it unavailable to any plants. Once the wood has broken down and is actively decomposing in the soil, that is no longer an issue. At most, any nearby plantings may require some supplemental N for a season or two. If you compost the wood chips before you incorporate them into your soil, you don't even need to do that.

btw, the dry weight of a cubic yard of arborists' wood chips is about 550 pounds. 10 cubic yards would only be around 5-6 thousand pounds. And not nearly as hard to move as previously indicated. I'm a little old lady and I have moved 18 yards of compost - much heavier than wood chips - all by myself.