Saturday, 22 March 2014


Healthy Soil

Giving plants all they need relies on good soil, something I haven't got as our little field is clay and compacted. Water can't soak away very quick and when it does the soil stays wet and cold for ages. The soil needs modifying.

The argument as to dig or not has been sorted out in my mind after a couple of experiments. Placing cardboard over the grass and weeds and placing compost and manure on top worked but none of the roots went into the underlying clay. If the roots don't go into the clay then holes aren't created to allow air and water in and also little creepy crawlies can't delve deeper.

I've done a lot of reading since then and can now see how a no dig, less effort soil can work but if the soil isn't right in the first place then it either takes time for a totally no dig approach to work or you need to speed things up and once started you can then never dig again.

I can see how not digging at all, even on a heavy clay soil, will work. You need to grow plants with strong deep roots which will plough their way down, like dandelion, and I think kill some of them off so the root dies leaving a hole that can be populated by water, air and micro organisms. Organic matter from above can fall in and or be taken down by worms. Having lots of organic material above the clay will get worms going and some will dig deeper achieving the same. Bit by bit the clay will get holes in, organic matter enters and life will start. For me that is too slow and I want to speed things up and grow a good crop now.

The farmers way

Looking out of my window I can see fields. At this time of year the farmer is preparing the fields for his crops. He's grown field beans and has ploughed them in to provide nitrogen. He had previously placed a huge pile of manure by the side of the field. It's been steaming away for a while but hasn't broken down totally. That has now been spread and ploughed in.

What's happening is that he is adding organic material and nitrogen and is then allowing the bacteria to continue to break down the organic material before he sows the crop. I think he will till the soil (I think that's the correct term) before he sows. Tilling once more is like stirring the soil to mix the organic material more with the soil but also which gives the bacteria access to organic material that it hasn't worked upon yet. It also makes a finer bed for the seeds. It's the bacteria that turn the organic material into nutrients and help to break it down into something useful.

Just doing this isn't enough often and so he will apply fertilizer, weed killer, pesticides and what ever else. He doesn't have the time with his method to allow the soil to live and be healthy and his pesticides and weed killers, slug pellets etc. will kill most of the micro organisms which would normally (in nature) take his prepared soil and continue the process. He still manages to produce a good crop and repeat (sustain) the process year after year. Of course sustainability is in the context of commercial short termism.


Putting manure in piles is just a way of speeding up the bacteria that break it down by generating more heat and they have more food to keep the process going rather than just one patch on the field. Manure is good organic material which has already had a bit of processing done on it while in the animals stomach. Using manure is just the same as placing grass and other cuttings directly onto a vegetable patch only the initial process has already taken place. It may not contain as many minerals as green material as the animal will have taken some out but it comes in larger more compact amounts. It's simply a quicker way of getting minerals and organic matter into the soil. Manure can also act as a mulch fertilizer to feed plants or just a mulch to protect the soil.

Soil Structure

To get good soil structure humus is needed. Humus is simple organic material that has been processed by micro organisms, and other organisms, to a point where no more processing can be done. It becomes stable when fully processed and serves as a permanent part of the soil giving the soil the ability to hold moisture and minerals.

I think compost is basically the same as humus, organic material that has been processed.

In addition to humus soil needs particles,  ranging from sand, through silt to clay. Clay is just fine particles. A good soil needs a mixture of different sized particles made from different rocks bound up with plenty of humus.

I'm using large amounts of manure simply because I can get it trailered in, free, and from a local source which makes good sense. Obviously using compost will add humus to the soil and give good structure but I don't have enough of it and if I wanted more then I'd have to buy it. I'm hoping that using manure will not only make my humus but also wash down minerals and nutrients into the clay both fertilizing and creating humus at the same time.

Adding sand is something that I have also done but I think the amount is a bit small and I don't have any more. As time goes by I'll add more.

A Living Soil

Once you have a soil structure, sand, silt, clay and humus you want it alive with large and small organisms. Micro organisms are the small ones that you can't see and everything else you can see with your eyes are the large ones. Living organisms need food, dead roots, any organic material and moisture. I think the dead bacteria left over from processing organic material is also food. Another reason for me using manure is that when it has been left in a pile on the ground the worms underneath come up to eat it and multiply rapidly. I first make a pile of manure, wait, then move it to a bed taking worms with it to the bed. Various other organisms will also come along.

To turn my compacted clay field into a new bed I have started to dig up the turf and put it back upside down. Loosening the clay beneath the turf as I go. In the past I would have removed the turf and dug deeply breaking up the clay as I went but this is taking far too long. The hope of doing things this new way is that the grass turf will die, leaving root holes and provides food for the organisms. Piling manure thickly on top will smother the seeds and weeds that wouldn't die, add more worms, and the sheer depth of the manure will hopefully be enough to stop the really strong weeds, like dock and nettle, from finding the surface. I'm hoping that as the grass and weeds die they will leave holes and a softer clay behind for the worms to break up even more. Nutrients will wash down from the manure into this turf layer and below as well as some organic matter being washed down. Worms can take down even more which will slowly achieve the farmers "stirring" or ploughing and mixing.

I'm hoping using fresh manure directly onto the bed will be faster than waiting months for it to break down and then placing it onto the bed because it should break down and be mixed with the clay at the same time. Placing it on a bed rather than in a pile should also provide more air for the bacteria and at the same time keep it cooler so that the other micro organisms can live there at the same time.

Normally you have to use well rotted manure because fresh manure has too much ammonia and nitrogen in that will burn plants but I'm hoping these will be converted quite quickly and washed and diluted deeper into the ground before I plant. The manure will be 2 to 3 months old by the time I plant which should be enough time for ammonia and nitrogen to no longer be an issue.

Another problem with using fresh manure is because it normally contains many weed seeds that will germinate, how ever I find that no matter how hot my manure heap gets while it is rotting down I never mix it well enough to kill all the seeds and weeds always appear anyway even with well rotted manure. I'm ignoring the weed issue plus I intend on covering the soil surface with plants and mulch which will help prevent weeds.

There is supposed to be a health risk with using fresh manure. E. Coli, round worms and tape worms among other things and you are told that if your manure heap reaches 140 degrees F these should be killed. From what I have seen of other peoples manure heaps they are often too small, lack oxygen and never get hot enough to achieve this anyway and problems like this seem to be rare. Many people are so risk averse that this is probably over worried about plus I have read in several places that a good healthy soil will contain things that will eat E coli. The main defence against these things is to not eat until you have washed your hands and cook things properly, Vegetables should be properly washed before eating. These things are present all over the place anyway where animals are. General hygiene is the best practice. Also the place where the manure comes from regularly treat their horses for worms which will prevent much of the problem.

This is where we depart from farmers

So far much of what I am doing is the same as the farmer, minus pesticides and minus proper digging that is. Bacteria and organic matter and at least some of breaking up the soil is the same.

Once the soil is living, nutrients and minerals that the plants need to feed on get converted in various ways. Nitrogen is in abundance in the air but plants can't use it in that form. Bacteria can take Nitrogen and Hydrogen and produce Ammonia, then bacteria change the Ammonia into an organic compound which means it contains Carbon. This is Nitrogen fixing. Ammonia gets converted to Nitrite and then to Nitrate via Bacteria. If the soil is dead or is not healthy enough to support these Bacteria then Nitrogen will need to be added in a different form. Nitrogen is the most important nutrient to plants.

Phosphorus is the 2nd most important nutrient to a plant (and the micro organisms in soil) and perhaps the most important reason for growing food in a sustainable way. Farmers add Phosphorus or phosphates to the soil because their soils don't have enough "usable" phosphorus for their crops. There is plenty of phosphorus in soil but it isn't usable in it's natural form. Like most nutrients it needs to be soluble for the roots to take it up. Farming practices, cropping, takes out phosphorus within the plant which depletes what is available. The only ways to put it back are via organic material (manure),although this isn't always enough when plants are cropped intensively, adding it as an artificial fertilizer, although the world has a finite amount that can be mined and the price will rise, or by using micro organisms such as bacteria, fungi and actinomycetes, algae and mycorrhiza to turn the non-usable phosphorus into soluble usable phosphorus.

Permaculture techniques such as no dig and organic mulching win over modern farming practices in this area since not disturbing the soil allows these bacteria and fungi to grow and perform the vital role of providing phosphorus in a plant usable form. Agriculture in due course will have to find another way of adding phosphorus to the soil as the current method is not sustainable. The fertilizer industry is currently looking for a way to isolate which micro organisms are responsible, and best, for producing usable phosphorus and then they need to bottle it and sell it.

I don't know how intensive my crops need to be before the adding of manure isn't sufficient but adding phosphorus is another reason for me using manure but in due course I hope that my soil will build up enough living organisms to provide for itself.

Developing fungi in the soil to provide usable phosphorus has the advantage that the mycelium strands can stretch far and wide to obtain phosphorus and bring it to the plant roots rather than let the roots find it. This may well be the biggest benefit that mycorrhiza gives a plant.

Other nutrients and minerals are also oxidized and made soluble for plant use by micro organisms.

We're back to dig or no dig issues.

 Clearly disturbing the soil will destroy beneficial micro organisms, especially mycorrhiza fungi, but I feel most organisms will be not badly effected. The larger ones like worms can survive a good dig, as can a lot of bacteria. In fact I've read digging or "stirring the soil" can expose bacteria to more organic material which can be beneficial but I can see how damage to mycelium, especially mycorrhiza. would be detrimental since if you break it's strands you have limited the far reaching ability for it to take moisture and nutrients from a wide area directly to the roots. I haven't yet read how long it takes to establish a good mycorrhiza but obviously once established it is something you want to keep.

Some crops like root vegetables will make it impossible not to disturb the living soil so I can see a case for separating root crops from those above the ground.

Clearly organic gardeners produce good crops and regularly dig and are able to sustain these good crops but when you add in the no dig lack of effort and much evidence that you can obtain better crops when mycorrhiza fungi work I feel that I can use a polyculture of plants that help each other, such as deep tap roots to bring nutrients up from down below and combine what I see in nature which is returning organic material back to the surface as a mulch, such as leaves dropping, grass dying and falling, annuals dying and being returned to the soil, with perennials which do not need to be pulled up and combining a manure mulch to help fertility and making sure the ground is constantly covered to keep down weeds and retain moisture.

At the same time I can keep a good soil for my root vegetables by separating these and continuing to dig these beds and adding organic material in the form of manure.

Different plants to choose and different methods to use

If most of my beds are to be a no dig bed I can see that I need to find perennial versions of some crops. I use a lot of onions and garlic. Sometimes onions are used vegetables, sometimes more for flavouring and as additions to a dinner. Welsh Onions and Garlic chives and perhaps wild garlic would seem to be good plants to use when the flavour is needed and perhaps I can reduce my onion patch. Although I do roast Garlic gloves as a vegetable more often than not I chop up finely and use as a flavouring so a non digging up leaf version will suffice.

Rather than pulling up a crop including it's roots, I can see that often it will be better to cut the plant and leave the roots to die in situ.

Because the ground will need to be covered at all times I can see the need to choose different plants and perhaps have some growing in pots ready to replace the ones I crop, or when I crop a plant in a polyculture I can see that would be the time to add a manure mulch just to the area which has become bare.

Bit by bit, learning about soil, I am also slowly becoming aware of changes I need to make and the benefits of doing things differently.

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