Advice for dense clay soil

Hi everyone,

I am in the beautiful task to regenerate a 1ha , dry, dead clay soil.
There is almost no plant on it but I am getting lot's of organic material from some prunning companies who regularly drop me their truck load.
Still, I have hard time to find hardy plants that grow nicely in that soil without having to add extra better soil to it. (even leucaena, cajanus cajan doesn't look like to do well).
I planted also some oat and barley for their strong and deep roots but they are doing more or less too...

Now we do have quite some rain coming and some parts of the land have native seeds coming out but some big parts have nothing growing.

I am mainly looking for a ground cover and some trees that could begin to make some shade for the summer to come.

I also have trouble to germinate tipuana seeds even with boiling water....

Here a picture:

Thank you for your advices

The best advice that I can give is to continue what you are doing: keep layering with the prunings you are getting. Do not worry about how thick it gets. Once those rains come that you talked about it will go down fast. You might consider dividing your land into sectors. Get one covered really well, go on to the next, recover the first, etc.

Soil on my farm was similar to yours. When soil is bare and compacted it absorbs heat much like asphalt does. Temperatures on the surface can reach as high as 140° to 160°, especially where you are in Texas. At these temperatures, there is little to no microbial activity in the soil. Moreover, most seeds will not germinate at high temperatures. The reason why things that you have planted are not doing well is because the plants are spending all of their energy on transpiration (analogous to circulation and breathing for us) and have little remaining energy to build tissue and grow.

If you have access to water, try to keep the prunings moist, as it will accelerate decomposition. Do not worry so much about planting right now. The prunings that you are getting likely are carrying some seeds, which will sprout when conditions are right. This will be a signal to you that the soil is ready for you to plant things that you want.

The keys right now are lowering soil temperature, build its water holding capacity, and build new soil on top of your compacted clay. All can be accomplished with the prunings you are getting.

Just in case you doubt what I am saying about soil temperature, try walking barefoot on your land between 10 am and 2 pm

I started my garden in Tenerife clay with corn. You get a lot of root mass quickly. When the corn is 2mths old interplant peas and beans. Just let the plants fall over when they're done. In 3-4 mths you will be ready for leucaena, yuccas, canarian palms, prickly pear, fig, squash and these will make it thru the summer with minimal irrigation. I'm in the south of Tenerife where we get much less rain and a bit more sun than you. Might be getting some rain this evening and later this week, very exciting.

Yes, thank you, I should put more energy into that then trying to plant plants that will shade the soil for the moment.
I am hesitating to rent a shredder to make all the organic material into little pieces or not as they will decompose too fast maybe. What do you think?
The main material we have are palm leaves.

Let me echo the voices above: keep mulching.  Carbon is the solution.  Wood chips will eventually transform that heavy clay into friable soil.

Dandelions and other weeds are your friends --- let them punch a hole down into the soil.  Other cover crops will serve to soften and penetrate the soil profile, and add to the biomass (both above and below he soil line).  

While you mulch heavily, you might want to amend smaller "pockets", and plant vining plants like pumpkins or sweet potatoes that will reach out and cover he mulch.  They'll shade the soil and provide additional biomass.

What I wrote basically still applies. I am about 12° N of the equator in Central America, so I too have access to palm fronds. Although they are great for covering the soil, they tend to decompose slowly. How good are you with a machete? I would recommend chopping most of them up for faster results. A wood chipper would do this too. Spread or rake the pieces out onto a sector. Then, lay whole fronds on top.

hau Michael,

I would recommend that you do some water management first so that you can stop the erosion that is showing in your picture. Find the Key point (where runoff starts to converge) and install a pond there then run your swales and berms out towards the ridges at a 1degree down slope.
Doing this will allow any rains to soak into the soil, which will allow covers such as grasses, clovers, etc. to grow and sink good, deep roots into the clay.
As the cover crops mature you can then bend them over and let them become your mulch, replant either food crops or a reseed of cover crops to let grow to maturity again.
Once you have the water control in place you can decide if you would like to put in rows of trees with alleys for vegetable crops.
If you keep in mind that it will take a few years, you can have crops at the same time you are building the clay into top soil without having to bring in any amendments.

A tree that will work well for providing shade quickly, food crop and fodder crop is Moringa. It is very draught tolerant and will do fine in clay soil.
It will grow quickly and then can be coppiced to provide fuel and it will come back with many suckers which will spread for even more shade.
It also will accumulate any contaminants the soil contains, if you do have those, be sure to have anything you harvest tested for heavy metals before consuming or feeding animals.

Redhawk

6 months have passed and I am still with hard time to get through this cement like soil.
I already lost quite some fruit trees that have not been planted with 50% straw (we did not have in the beginning) and only good soil (not one drop of the clay soil.
Even now I get some brown spots on the leaves of the fruit trees as the water stay stagnant after too much watering.
The only tree that is doing ok is El Tarajal (Tamarix Canariensis). I get to grow quite some wattle acacias but they stay tiny.
Bananas and some veggies grow but only with imported soil.

I am soo looking forward to get some weedy crazy growing tree to make holes in this ground.
Any new advice is much welcomed.

Here some new pictures

I showed pictures of the soil although many places are now heavy mulched like in this picture

Daikon might be a good plant to try, they grow huge and when topped the root will rot in place thus adding good humus after the ground breaking growing.

The best tree for what you need to do is still Moringa but if there are any weedy trees where you live, those would be a grand choice, since they already grow in the area.

Tall grasses send down deep roots that break ground as well as bring minerals up, things like Lucerne (alfalfa), cereal rye, barley, oats, wheat are all good choices for this.

Redhawk

You need to find a source for tons and tons of biomass.  Obviously, if you can grow it yourself on site, that's best, but importing it by the truck load will radically speed up the process.

Can you get tree trimmers to dump wood chips on your land?  From the looks of things, you could easily absorb several dozen loads.  You have to find a way to cover that soil with carbon.  Until you do, the sun will continue to irradiate all microbial life and bake what little moisture you have right out of the soil.

Consider planting some sort of pioneer species tree --- a junk tree that you have no intention of maintaining long term.  Nature tends to do this if given time.  Weeds and junk trees are usually the first things to grow in inhospitable environs.  Once they have built the soil carbon level and created a micro-climate where bacterial and fungal life can return to the soil, then "better" trees and plants can survive.

In our area, you see those Mexican Fan Palms growing along railroad tracks and other inhospitable places.  They tend to grow anywhere.  UGLY trees, yes, but they put out a massive root system that pumps a lot of carbon into the soil.  With minimal irrigation, you could plant a forest of trees like that, and within 5 years, they should transform your soil.  Then you chop and drop those pioneer species trees, hugel them, mulch the branches . . . and plant your other stuff underneath them as the soil improves.

Get biomass.

Plant it, truck it in, do whatever it take . . . you need to cover the soil with carbon if you ever hope to decompact your soil.

My soil was a lot like that when I first started, so sterile and barren that even the weeds didn't want to grow. There was no life there.  During the dry season it baked into a solid brick. A pick ax couldn't break through it.  I worked in one small area at a time, chiseled lines like small furrows on eyeball contour, about a foot apart, put handfuls of compost in the lines (only a little because I never produce enough compost for all my projects) and then I planted tropical nitrogen fixers - cowpeas and sunhemp croloteria are pretty rugged and will sprout quickly.  I mulched between the lines with whatever goodness I could find.  Note that I left the soil slightly hilled between the lines - like mini swales and berms, so that any rain was channeled into the lines.  As the mulch broke down, it also went down into the little valleys.  The point was just to get something, ANYTHING growing to start some life.  Those first cowpeas were the saddest, stunted, scraggly little things, and I didn't harvest a single pea.  But that wasn't the point, these are sacrificial. We ate some leaves but at the end of the season they became more mulch.  Like others have said, try to keep the soil covered.  I have a no naked earth policy... I can't always keep up, but I try.

As for bananas, we dig a pit, about 3 feet wide and three feet deep.  We throw all the organic goodness we can find into the pit.  Compost, weeds, manure.  Then we plant the banana and fill the hole partly back in with clay, leaving a good, one foot depression for catching water and further mulching.  It works very well.