Tillage radish and other roots as Carbon sink

Before you read this and get the wrong idea, I do a lot of no till. the tilling I refer to is for a medium sized annual garden.
I did a search of the site and came up with nothing on tillage radish. It's just a big Dicon radish used for growing corn in no till crop rotations (usually using herbicide). Anyway it puts a lot or carbon in the soil in a really fast way and it dies in winters with frost -6 or lower thus decomposing and releasing nitrogen and other nutrients at the correct time for the corn (or other annuals).

Anyway today I tilled up a patch of daffodils to use as an annual garden and I started thinking hey here's a plant that can be left in the ground for longer periods collecting carbon and nutrients which can be tilled up and used any time of the year (I grow alot of onions and other fall and spring active plants and tillage radishes may work for fall if tilled in early summer but are not so good for the spring season). So lots of plants store up carbon in the soil, some are weedy (sunchokes, comfrey) and re-sprout setting back the crop you wish to grow. Others Are more difficult to grow or have a higher value, like potatoes (you wouldn't just till up your spuds). So what we need are tuberous plants that do not re-sprout when tilled, are not costly and can (A)die off, or (B) be tilled under, at different times of the year depending on the crop we wish to grow off of their dead bodies. I wish I could find a tuberous plant that would just die off like the radish but I want it to die in august (when it gets really dry) so it will be decomposed by spring.

In conclusion I guess I could just till some radishes under in august and plant the dormant bulbs directly in to the area this would deprive the bulbs of nitrogen in the fall but in spring they would get a good boost. Man typing this out really helps my poor brain to think.

evening primrose has a spiked tuberous root and if your putting it under in august it will never see it's tall growing flowing stalk phase unless you want more biomass. I use it for soil stabilization in boggy territory that goes crust arid in the late summer. But you can get a tonne of seed off it and it grows really fast without regrowing from chopped up roots. Burdock is even bigger but now your messing with an edible crop again which is way more valuable than a potato. It's not daikon carbon sinking but it's off the edible list for us I think but the ducks and rabbit's will chomp into it.

In permaculture, the idea is to plant Daikons so that you don't have to till. You plant them, they break up the soil with their roots and then you leave them in the soil to decompose over winter. Now you have lots of pathways for air and water to infiltrate.

I've got some poor "pasture" on ledge and I'm planting forage turnips and daikons to till for me because I couldn't use a tiller even if I wanted to. I put pigs in last fall to really dig it up too.

You may also want to look at oil seed radish. I am looking at Burdock myself. It takes two years to seed and has a deep root. I have heavy clay soil and it is one plant that grows well.
I am thinking of harvesting it for mulch in the second year before it goes to seed. This way I get the deep root and a useful mulch without the bur issue.

Tillage radishes (or the much cheaper daikons) are typically planted summer/autumn. The idea is to get maximum growth before the first heavy frost kills them. They are then allowed to decompose where they grew, in the soil. (No sense tilling them in - they have worked hard to grow organic matter deeper into the soil than you could have tilled.) As CJ pointed out, this creates pockets (1-2 feet deep) in your soil for the air & water (+ worms) to penetrate. They won't completely decompose until after next summer/autumn.

If you live near suburbia, be forewarned:
they will stink to high-heavens - neighbors may call the gas company to report a gas leak!

If you don't plan on growing anything else there this season, I don't see why they couldn't be spring sown.

John Polk wrote:
they will stink to high-heavens - neighbors may call the gas company to report a gas leak!

Good to know! I hadn't heard that before.

I take that back it's plenty edible, but you wont eat the root's and i'd rather eat more of my linden/lime tree than go hauling up primrose for soups most of the year. Slug's don't seem to like it which means they live in it because of it's high drought tolerance and water retention. I don't think i've ever seen it wilt to any degree worth considering but they'll go down easy in the high summer.

Thank you Saybian.

The thing is the radishes (left to die from frost in my area) suck up nitrogen and other nutrients and release them mostly during the months of May-July and my winter active crops need nutrients mostly during September-December and then again from March-may. By may 30 they have done most of their growing and although the late nitrogen helps them a bit it also helps annual weeds, what I try to do is have most of the nitrogen used up by about may 15 when the annuals start to take off. So using tillage radish in the regular way would be counter productive when dealing with winter active crops.

Also in areas with winter frosts of no colder than -5C the radishes can survive for extended periods thus locking up nutrients for longer and releasing them more sporaticly as plants die one by one over time. This is not so bad but not so beneficial for corn yield, (corn and soy are the main crops that tillage radishes are used for). Corn needs nitrogen mostly during the first three months of growth. I still plan to sow the radishes with corn during the 3rd month of growth but they will be harvested as animal feed and not left in the field to rot.