The best fertility enhancer

You quoted words by William Blake that the mind of man is a garden already planted and sown; it’s a question of cherishing the plants already there. I think this applies very much to the soil as well.

They speak of fertility being “locked up” in the soil, and one of the main aids of promoting fertility is not something one puts on so much as releasing what is already there. It’s a question of allowing such things as soil roots and earth worms to make channels in the soil and therefore make a circulating system so that energy and fertility that is already in the soil is free to circulate.

-Robert Hart

Speeding up succession can take some strange forms, especially as tilling.

Tilling was originally introduced as a fertility enhancer, ‘bringing light into the soil’ as the ancient Zarathustrian texts put it. Today, science is well aware that oxygen, and several other components of air (nitrogen in a roundabout way), play crucial roles in the fertility of soil and the breakdown of organic matter. Tilling makes a huge surge of breakdown of organic matter, hence fertility, by shoving a ton of oxygen into the soil while killing a lot of the soil life -more organic matter for breakdown. It’s a goose that laid the golden egg situation though, as this massive onslaught cuts future fertility short unless things are carefully managed.

As you may have noticed in Niche in fertility, the fertility corresponded with fine tilth (fluffiness) of the soil. I use natural means of getting a good tilth by mulching. This worked because the mulch held moisture and food that attracted worms, and killed the resident grass, leaving a ton of organic matter and little tunnels for air to enter.

Remember too, if I neglected replacing the grass with preferred plants, the soil structure went flat, hard, dead.

This is because plant roots and soil life maintain soil structure. It’s worth noting the excellent results I get from mulching aren’t just from the mulch, they’re also from the grass I’m killing underneath. The deeper and more prolific the roots the better the end result.

The average lawn, even if the nicely clipped grass is green, won’t offer quite the same benefits. By cutting the grass short, we cut its roots short, as roots grow in relation to tops. Without grass clipping or leaves to feed worms, there is little insect or soil creature activity, so about 4 inches down the soil is hard as a rock and lifeless.

I have had the luxury of letting mine grow as tall and as deep as it will with only one or two mowings a  year. Those roots are deep as they can get.

In short grass situations, a good compromise is to get air into the soil by sticking a garden fork or shovel into the ground and gently lifting -not turning, just loosening. This keeps the delicate strata of bacteria and myriad soil life in order but allows roots to penetrate soil that would be very hard to break up.

I’m bringing an area of my parent’s greenhouse into production that’s been under two layers of plastic and one of weed barrier for years now. The soil is completely unamended clay. I know from experience in other parts of the greenhouse that plants cringe at the idea of puncturing their roots into this kind of stuff and just throwing a layer of compost on top will make for stunted plants.

I’m not too keen on tilling either, but I’ve got a schedule I have to adhere to so succession needs to happen fast.

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Not some ancient script. These shovel and garden fork holes are good stuff to get plant roots, worms, and air into the soil.

So I pryed the ground. In some spots (notably by the edges of the plastic) it broke up and cracked whereas others hardly budged. You can see the hardness of the ground in the collateral damage of the mission. I had to finish with another shovel.

I finished the plot in about two hours.

Bill Mollison was quite a proponent of this method of soil rejuvenation as prescribed for Keyline systems. On a large scale this was done with a keyline plow that cut into the soil violently. This shook up the soil on top of slicing it, and in Permaculture I and II Mollison praises the effects, highly recommending it for speeding up succession.

So the next time you start a new bed, take into consideration whether the soil is compacted or not. The effect of a quick pry with a garden fork may save years of succession time. Strange I know to bring any tilling into the picture, but done right, it does hardly anything but good.

11 comments

  1. I was very interested by this. I do a lot of tillage, and in my very heavy and alkaline clay it seems to me to be essential for good results in many areas. I have written on my blog about the experience of resolving to repair a hard-packed area without digging: I built a long low compost pile over the whole area the first year, then in the second year planted the compost with daikon to break up the impaction underneath. The daikon tops looked great, but when I tried to plant into it at the end of the second year, I found that the daikon roots had all turned 90 degrees when they hit the impaction and the soil beneath was as hard-packed and impenetrable as ever. So I gave in and broke up the whole area with a pick. Sometimes there is no way around sweat equity.

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    1. I have to first admire your sensibility to try no-till, and second that you would have the gumption to break it with a pick. Impressive.

      Building a compost pile and introducing worms would have been my first choice for the greenhouse area if I had more time. Ensuring the compost had calcium-rich material would be key as it breaks up soil particles -a process known as flocculation. Worms would be a good alternative because they concentrate calcium in their slime to help them break through soil. Did you have many worms?

      I imagine when you say clay you’re talking very hard clay though, which in my mind would verge on needing dynamite to get things moving. the compost method might have worked, but that might have been a decade later. I think you made a good choice.

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  2. My garden is clay with a lot of stones in it. It is very hard and difficult to dig into when necessary, for example to plant a tree. In parts I have been letting roots do the work of penetrating the soil – root crops like carrotand Jerusalem artichoke but also just plants of many types letting them get to work on the soil and keeping as much growing as possible all year round and only removing those roots which have to go (things like buttercup). It does seem to have worked. I am wondering if they managed to get down into the soil because of the stones which would give a way to go round and down rather than just hitting an utterly impenetrable layer. What do you think?

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    1. I’ve read some fascinating studies and the benefits of rocks from Dr. Phil Callahan. The very slight magnetic fields (so small they are call paramagnetic rather than magnetic) is supposed to help structure the water particles for more efficient metabolism and tissue building. Also, as compared to clay like Wooddogs has rocks are potential nutrients, whereas clay is worn out rock which can be quite depleted of nutrients (the capacity of clay to bind to nutrients is part of the cation exchange capacity). So there are many potential benefits of rocks.

      I haven’t heard much about them offering mechanical assistance though. I imagine they would move less in freezes and thaws and might have little gaps around them that might act as suggestive pathways for plant roots.

      Leaving the roots in the ground is definitely very smart. Each new plant can use the “carbon pathway” of the last plant’s decaying roots and each time move a little deeper.

      Leaving the plants and hence humus chemically gets the soil active as I mentioned in my reply to Wooddogs above.

      I think rocks have a lot very subtle effects that build up to noticeable effects over time. Of course, your sensible management is a big part of that.

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  3. Anni, I’m eager to hear what Mortaltree has to say about this. I think you are right. Many years ago when I lived in northern New York and had stony clay soil, I used to plant daikon to break it up and it worked fine. The stones create a path, and freeze-thaw heaving the stones creates even more space for roots to extend into. In my current garden, with no stones, it doesn’t seem to work.
    One exception is that if I plant alfalfa and let it grow for at least two years, that seems to break up the clay pretty well.

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      1. Alfalfa loves my alkaline soil and improves its fertility, and I cut a lot of greens for my chickens and always let some go to flower for the bees. It’s an incredible plant, and doesn’t need much watering even in my desert conditions once it’s established.

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  4. In the Southwest we have a special kind of highly mineralized clay, the kind that adobe bricks are made of, and there are adobe houses still standing after a hundred years or more, so our clay is to be respected😉. I dread using my pick, and ache for days afterwards, but it is my best gardening friend. Once the soil is broken up, plants seem to do a very good job of keeping it more open. I have developed the strongest kind of respect for alfalfa. I have read that the roots can go 30′ deep, and I believe it.

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    1. I’d love to get my hands inside that clay someday just to get to know it.

      Alfalfa is wonderful at growing deep. I’ve heard notable anecdotes about it puncturing hardpan. Where I live is a big more wet and dreary then it really likes though. Within two years from planting it often starts dying off.

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