Can someone please explain “carbon locking up available nitrogen”

Or refer me to an article or thread? I'm interested in learning more about soils and after reading through several threads I've seen this mentioned a few times. Specifically for my situation I have a 26x40 space where I’m removing the top layer of grass. I plan to use a broadfork to loosen the soil. Add bagged 2 yr old leaves and ash/sawdust from the pellet stove and broadfork in again. Lay a small layer of compost on top then plant. It’s going to be a mixed area of perennial and annual herbs, flowers and vegetables. I planted a Siberian Peashrub along the top middle edge of the garden. Is what I’m doing going to cause an issue with locking up available nitrogen? In another soil thread Paul mentions that this can be mitigated. What are the ways to mitigate this? Thanks for any feedback.

Aaron Festa wrote:Add bagged 2 yr old leaves and ash/sawdust from the pellet stove and broadfork in again.

It's the sawdust you don't want, it will take too long too break down "locking up nitrogen" while that takes place. You might be careful with the ash, depending on how much you have might swing the pH too much.

Save the sawdust for your paths to help suppress weeds.

http://whatcom.wsu.edu/ag/compost/fundamentals/needs_carbon_nitrogen.htm

^This.

Your location indicates New England, which is the Blue Berry capitol of the US.
Blue berries only perform well in acidic soils. Ash is alkaline.
If you have blue berries, don't get ash anywhere near them.

Peaches, on the other hand, love ashes.

Ash is a wonderful, free resource if you wish to 'sweeten' your soil.
The sawdust is best saved for adding to a very green compost pile, where carbon is needed.

The greater the surface area of the carbon that is intouch with the soil.
The faster the microbes can eat and digest it. When the microbes eat, they multiply.
To multiply they need amino acids aka nitrogen. Where do they get this nitrogen from.
They get it from the soil, the same nitrogen that the plants are looking for.

So to slow down the speed at which the microbes eat the carbon, we want to use big chunks of carbon.
That is wood chip vs sawdust. And we dont want to mix the carbon with the soil/compost or but it below the soil/compost.

Next we want to increase the amount of nitrogen that is available to the microbes and plants.
We accomplish this by planting nitrogen fixers such as white dutch clover.
It produces the "most" amount of nitrogen and only get to 8inches after years of being left alone, never cut.

The east coast soil is low in "ash" minerals so adding some is a good idea. Just make sure that it is spread evenly and that not too much.
Plants like blueberry are adopted to the native low ph soil of the east coast. So if you change it with as it will not like it but other plants will like it such as peaches.

Overall other than the sawdust and you covering the woodchip with soil/compost your plan sounds wonderful

I have a better understanding now and I will make the changes based on everyone's input. Thanks again.

Basically, plants eat last.

Bacteria eats first in order to break down the sawdust, and they need nitrogen to do this. The bacteria in the sawdust will not mine the soil for nitrogen because they are higher up in the sawdust, but if you put a little fertilizer on top of the sawdust then the nitrogen in that fertilizer plus what is in the sawdust can be used up by the bacteria before it ever reaches the soil, and the plant might not get enough nitrogen, as it has to go through the rotting sawdust and the bacteria gets to it first.

Of course after the sawdust has been composted the bacteria dies back and the nitrogen they used is released along with the nitrogen in the sawdust and so the plant will eventually get it, but sawdust takes time to break down.

Ruth Stout, who used a deep mulch method, added a layer of fresh straw to her garden every year. The straw at the bottom of the mulch was pretty well broken down and releasing nitrogen while the straw at the top was fresh, and so every year there was a layer at the bottom releasing nitrogen while the layer at the top was just beginning to break down. Plants loved it, as they got their dose of nitrogen every year from the bottom, rotted layer of straw.

Terri Matthews wrote:
Ruth Stout, who used a deep mulch method, added a layer of fresh straw to her garden every year. The straw at the bottom of the mulch was pretty well broken down and releasing nitrogen while the straw at the top was fresh, and so every year there was a layer at the bottom releasing nitrogen while the layer at the top was just beginning to break down. Plants loved it, as they got their dose of nitrogen every year from the bottom, rotted layer of straw.

I've tried that and it didn't quite work so swell for me. But it might be my heavy clay soil, which doesn't really accept the straw, which stays on top. Also adding lots of straw might lead to potassium levels getting out of balance, so people might want to watch out for that. One thing that potassium does do well is give structure to plants, so the plants might actually 'look great' but actually be deficient in nutrients.

I really liked your post, by the way. Good explanation.
William

Terri Matthews wrote:
Ruth Stout, who used a deep mulch method, added a layer of fresh straw to her garden every year.

I know some Vermonters have trouble with this method because it takes the soil longer to warm up. You could move the mulch aside or cover with black plastic a week prior to planting.