getting organic matter into depleted soil + tree of heaven

I live in the central valley of California and in my area we have the most depleted over cropped farm land I've ever seen, the soil is composed of very hard light colored clay and rock that is difficult to dig through with virtually no organic matter. I'm looking to improve the soil and have started a small experiment using ideas I got from a permaculture documentary. I dug up an area of about 10 feet long and 3 feet wide approximately 4-5 inches deep and then I worked into the loosened clay a lot of stick and leaves I chopped down from some trees about a month ago, most of it is already decaying. I then covered the soil with a thick top layer of even more leaves and sticks.. I'm hoping this will provide an ideal environment for mold and fungi to thrive in so that the leaves and twigs break down even faster. My goal is to restore the soil so that it has a good amount of organic matter and nutrients for future gardening projects. I would like to get down deeper into the soil to break it up and was wondering if next year I could plant a type of grass or root vegetable like carrots or potatoes to break up the soil even more. Would this be practical or will I have to work deep down into the soil by hand? If you have any thoughts or advice on my project I'd love to hear it!


The area I'm working on.



These are the type of trees I used for mulch, they grow extremely fast, like weeds. (anyone know what they are?)

I'm guessing that's Tree of Heaven, Ailanthus altissima.

that is the dreaded Paradise, Tree of Heaven, Alley tree.

Let it decompose in the sun a bit before you bury it, or dry for 2 seasons before you burn it indoors.

Roots will travel yards at a time, and if you cut down main tree, the roots will shoot up suckers. DONT let it into your garden area.

https://permies.com/t/9273/woodland/kill-siberian-elm-tree-heaven#97908


You are doing exactly correct with the soil, but would add a few things if you have the time.

Char some of the wood, then smother to let it smolder without air. Dont burn it in the hole, it will kill any microbes that have survived in the soil till now.
Douse it with some seawater, and if you can, mix in some seaweed with the brush. If you can find a little rock phospate fertilizers, mix some in the dirt you are backfilling.
It appears sea salt has just about a perfect balance of stuff for plants, but salt water has too much calcium carbonate. Dont use much of either.
Dont leave the dirt you dig out sit in the sunlight, or dry out. Again, will kill any microbes and microlife in the soil that has survived till now.
Order some myco soil innoculant mix from Fungi Perfecti, or borrow some compost from an old neighbors pile to get the local blend started for your area. Drop in a couple scoops when you bury brush.

Try and leave a cross drainage swale (hillock) to capture winter rain, so it will soak down, instead of run off.
A laser level will help with this later. Even a cheapo 2 footer will help a lot.

Yes, that definately looks like tree of heaven. I think you've got the idea, but that's a lot of work your putting into a small area. How much acreage do you have? If it's a small amount, digging and adding compost makes sense to jump start things. However, both long term in small areas and any-term in large areas cover crop the place. Cover crop will work at the hard pan likely to exist somewhere between 15-18 inches down and it will provide food and structure to the soil that is so necessary. To be honest, I have a no-till bias. I've done it even on pots and never had a problem. Tilling also causes more water to run-off the soil surface than penetrate in along with destroying your soil in many other ways blah blah blah...

Anyway, now's a perfect time to plant a cover crop. I'd check out some tillage radishes, clover, and a nice fiberous rooted grain species. Or, if you want to just have fun, throw out a variety of seed and see what comes up. That will help you figure out what plants make the most sense to grow in your area.

In general though, for covercrops try to get a variety of plants and roots. That's what nature does. Look at the weeds - they are the "fixers".

I hope this isn't 90% ranting and 10% advice

I think the 'how much land' question is very relevant. Deep burial of organic matter, whether hugelcultur or compost or something in between, is lots of labor. Plant root action can be very powerful. Consider some nitrogen source for initial plantings... Some of the good tap rooted plants like mustards are not nitrogen fixers, and will work much harder with some imported nutrients... either rotted manure, or organic ammendments. Still plant your nitrogen fixers like the clover recommended, but consider a jump start if your are in a hurry. In general I think it is useful to work at two scales. Apply labor and import materials in a small footprint to accelerate productivity. At the broader scale use soil builders. SInce you are in central CA, water is a limiting factor... so the swale comment makes A LOT of sense... but preceded by observing where water is coming from and where it is runing, and how much water you want to catch, and where it will go when you overflow in a big dumping rainstorm. Water may be you 'limiting nutrient' as much as soil structure and nutrient reserves.

Watch the hugelkultur video - currently at the top of the page.

Thanks everyone for the replies. I have looked into clover and I'm considering buying some crimson clover seeds, mainly because I read it will work in clay soils and likes the cold. I'm going to borrow my neighbors rototiller in a few months to loosen up the dirt. I could also really use a chipper to grind up some nice mulch out of all the branches and leaves we have around here, but they are kinda pricey.

Rototilling is verboten in permaculture. You get short term gain but loose soil structure, critters, and so on.
You can sheet mulch to kill existing vegetation or let chickens or pigs till and fertilize for you.

I'm going to borrow my neighbors rototiller in a few months to loosen up the dirt.

I am seeing some amazing results in my compacted, rock hard clay, using Grow Organics sod buster and soil builder seed mixes. I tilled the area then seeded the mixes, then mulched lightly with some straw. It is to late for the fall cover crop mixes, but you should be able to get a summer mix in the spring. I would definitely recommend using the cover crops first, then planting trees and bushes into the mix during the second season.

From reading Sepp H. book, I am not even going to till or cut down my cover crops. I will just dig and plant trees and berry bushes into the area.

My garden is similar with heavy, low organic content, California peninsula clay soil.

You'll save yourself a lot of frustration (and work in the long run) if you just bit the bullet and dig in tons of organic matter all at once.

I tried and failed for 3 years, first with digging in compost, leaves and sticks, then no-till, then cover cropping;
it all wasn't anywhere close to being enough. It all returned to heavy clay the same season.

Digging in 50% wood chips, worked wonders for my garden. Immediately turned around a bed I'd given up on.

Hugel was good also, but only improved areas where rotten logs or dried vertical logs were buried.
In the first season; areas with dried, unrotted, horizontally buried logs didn't improve much.

No-till is a great ideal, that I hope my garden will be now.
But to get my soil up to where it is now after digging in 50% wood chips, would probably have taken a decade or more of no-till cover cropping.

These links have some pictures on what I've done to amend my garden soil:

http://lowcostvegetablegarden.blogspot.com/2012/07/first-3-years-of-failure.html

http://lowcostvegetablegarden.blogspot.com/2012/10/wood-chip-soil-pictures.html

Hey guys just thought I'd return and update my project here. As you can see in the pics I was trying to compost in a big pile on the ground, but I've since scrapped that method and am trying something else now. There was a large stump that took me about a week to dig out by shovel and what I had left was a great big hole. I decided to move my compost pile into the hole and I have been very regularly adding vegetable waste, lawn clippings and tree clippings, branches, leaves etc... The poster above me mentioned that no matter how much organic matter was added to the clay that it always returned to the way it was before, that's what I'm afraid of, so I'm thinking about changing the composition of the soil by adding sand. Would this be a good idea and what kind of sand do you think I should use? The goal of course would be to make the clay less prone to sticking together in large clumps and all around looser so that it's easier to work with. What do you guys think about this idea?

Also, I did plant some crimson clover and a green manure mix of common vetch, hairy vetch and 1 other which I can't remember the name of. I've been watering these regularly. So far the wild grass and green manure mix seeds I planted have completely grown over and crowded out the clover, so I am kinda disappointed about that. I was looking forward to seeing the clover bloom this spring but I don't think it will grow very much now that they are shaded out by the taller plants. Now I'm looking for a clay buster to plant for the summer.

Hi Ringo
I've always been told that clay+sand=concrete, unless you add an enormous amount of sand. Before the 1855 earthquake, where I live was the high-water mark, so I know sand
I say value your clay! It's really mineral-rich, and unlike sand, actually holds onto nutrients.
Organic matter on top and plenty of mulch should do it, but it's likely to be a slow process.
Maybe you could experiment: mix some clay/organic matter, no-dig some...
Will daikon grow in summer in your area? That stuff's amazing! I let the roots get massive, then hack them off at ground-level with my trusty cleaver, leaving the giant roots to decompose in the ground, and the tops as mulch.

Creating texture is a good first step. Mini-swales and small pits hydrate soil evenly, promote biodiversity thru microclimates, and collect organic matter from air currents.

Grasses do most of their work underground. About three quarters of consumption in grassland systems is performed by invertebrates that depend on die-back and regrowth in different root strata. Pulses of available carbon draw fungal structures up from below, further de-compacting.

I've had good results in similar soil by casting a combination of legumes and wild bird seed (mostly grasses) over a well-pitted area with just a little bit of mulch. The bird seed develops quickly, giving you a mat of carbon to at least maintain a toehold in the easily-collapsed soil. I've found added texture to be most important step overall, because it keeps water in the soil long enough (and creates enough edges underground) for the different invertebrates to stay active.