Healthy or Fertile soil?

Do we mix up the terms healthy soil and fertile soil? 

My contention is that that a healthy soil is one which has a diversity of species which are living in balance with each other.  An analogy would be when a pond eventually becomes crystal clear because everything is in balance.  The problem with creating a healthy soil is that it cannot be worked on and it cannot be cropped.  To do this would upset the balance by removing recycling nutrients, breaking symbiotic relationships and killing soil fauna and flora. 

Having said that, humans are part of the natural world and taking vegetation to eat in a permaculture kind of way must be fairly sustainable just as long as we return our waste to the environment. 

As we have seen from modern scientific agriculture, we can have a fertile soil which is very poor in biodiversity and is very unlikely to be sustainable. 

The trick is to be able to have a healthy soil which has a diverse population of organisms while also being very fertile providing crops to harvest. 

Although this is more likely to happen if we use organic methods, growing food is not a process that is conducive to producing a healthy soil.  Even in organic gardening we have to alter soil conditions to prevent pest and disease organisms dominating the soil population.  Do we just accept that we have to do this to produce food for ourselves or do we work much harder to find methods of growing that do not involve major disturbance to the soil. 

I would suggest that producing small areas of very intensive fertile soil which is as healthy as possible is the way to garden in the future.  I am not really arguing for no dig methods because they are not really viable in a proper cropping rotation.  This method is fine for handkerchief sized raised beds but not for allotment sized beds, although it does have its place even here.  I just think that a “no dig method” will not achieve a healthy soil when the next rotated crop involves digging to crop it – as potatoes do.   Taking crops out of the soil must    affect mico organisms because we are removing both rhizosphere habitat and food.   

Also, to achieve a high fertility in organic systems large amounts of organic matter have to be added to the soil.  This can be achieved by mulches but I would suggest that it is quicker and more effective to dig the organic matter, such as manures and composts, into the soil. 

If we are going to use the hugelkulture where brushwood is laid on top of the soil and covered with top soil to produce a raised bed or my Montezuma method where logs and branches are buried deep in the soil or even the chinampa method of the native South Americans, we will be breaking the soil and affecting the diversity and balance of organisms within the soil. 


All these methods of introducing large quantities of organic carbon into the soil together with the traditional composts and manures  may well alter the dynamics of the soil balance.  I would like to believe that there is an increase in the diversity and interrelationships of organisms within the soil when organic matter is introduced.  Realistically, there must be a cost to breaking the soil to crop it and this is met in the destruction of soil communities when digging and cultivation occur.

The ancient South Americans produced a very fertile black soil now called Terra preta by adding mulches of inoculated charcoal.  These soils are even now sometimes metres deep.  The literature suggests that Terra preta did have a unique population of micro organisms.  Could these soils be called both healthy and fertile?  The charcoal may provide habitats for useful micro organisms that otherwise would be preyed on excessively by the soil predators.  If this is so then charcoal will increase the diversity and possibly the health of the soil.  
Both increasing the health and the fertility of the soil in a balanced way is extremely difficult but if ancient peoples found a way of doing it, it must be possible.  

How I treat the soil for each of the vegetable types.

There is a science to gardening, however the variety of different soil conditions and environments means that growing plants is more down to knowing and understanding your own small growing area than the generalities of ideal conditions.


Is gardening  more of an art than a science?  Certainly the better you know your local conditions the better you can grow plants.


So all things considered the preparation of the soil for different vegetables probably needs to be changed depending on the plants grown.  I cannot honestly say that I prepare the soil particularly differently for any of my vegetables.  I might get an even better crop if I did but the general strategy is to pack as much carbon into the soil as it will take - and its appetite for carbon seems to be insatiable.


So what different strategies do I use for each of the vegetable beds?


During the winter I marinade charcoal in comfrey liquid.  This infuses the charcoal with nutrient and I add this inoculated charcoal to the planting holes of most of  the vegetables - until it runs out.


I see the peas and beans to be net contributors to the soil fertility.  After cropping they will be dug into the soil to add nitrogen. When I was young I was told that you should cut off the tops of peas and beans and put them onto the compost heap leaving  the roots in the soil. The roots add nitrogen.  This is true but roots only contribute about 30% of the available nitrogen.  60% of the nitrogen is in the stems and leaves of leguminous plants (peas and beans).  So, I dig these into the soil too. This will be done at the end of the year for the roots to get the benefits next year.  


If manure or tree leaves are available I will dig these into the pea and bean bed in the autumn and winter.  I put charcoal and a pinch of mychorrhizal fungi in all of the planting holes.  Together with that, I will water the peas and beans with comfrey, sweet cicely, nettle and worm bin liquid mix during the year.  This year I have been able to put a 50 - 100mm top dressing of good home made, friable compost over the whole area. It is full of weed seeds but I can put up with this because it is also full of nutrients. Chicken manure is sometimes used as a base fertiliser along the rows before planting.  


The comfrey liquid is not scientifically mixed.  Whenever I can crop each of the ingredients, I add them to the digester bins to rot down.  What goes in the bins, stays in the bins.  Everything seems to end as a liquid.


I do not add any farmyard manure or leaves to the brassicae bed.  The bed is given a good dose of lime to prevent the brassicas getting club root (Plasmodiophora brassicae.)  The plants are watered in with comfrey liquid and given charcoal in their planting holes.  The summer brassicas are given comfrey liquid to bring them on during the summer.  The winter vegetables are given nothing because they seem to fair much better if left to fend for themselves.  If you feed Brussel sprouts too much, the buds will "blow" or open out before they can be harvested.
Cauliflowers and cabbages do like to have nitrogen in the soil and this is added in the form of chicken or pigeon manure during the winter or early spring.  


The onion bed gets as much organic matter as I can find.  That is farmyard or horse manure, leaves, grass mowings, weeds etc.  The onions seem to relish lots of organic matter in the soil.  This is another bed that I covered with a top dressing of home made compost.  Great stuff except that it has a lot of weed seeds in it.  When planting, I put charcoal and mychorrhizal fungi in the planting holes.  The onions are watered with comfrey during the year but the solution is very dilute. Onions do  not like too much nitrogen in the soil.  The do require a damp root run and just watering will do this more than adequately.  Really, for my rotation system, I should be liming the onions to keep the pH quite high -to about 6.5 to 7.5.  I will do this in 2012.


The potato bed had quite a lot of horse manure and leaves dug into it last autumn.  They were planted with charcoal and mychorrhizal fungi.  They have had nothing else.  I have not even watered them.  If pigeon or chicken manure is available then that is used on the potatoes as well.  


The roots did not have anything dug into their soil except the old bean and pea haulms; grass mowings and weeds.  This will avoid the problem with forking that manure stimulates.  I put comfrey liquid in the sowing drills and a little mychorrhizal fungi.  That is all that they have had this year.  I have watered them  during the very dry weather.


And that is it more or less.  So if you do this for 30 years or so you will get an allotment as good as mine.  


I cropped the garlic yesterday and it has white rot in some of the bulbs.  I had to throw away about 6 of them.
The others are drying in the store shed.
I harvested one large lettuce, some American land cress and some spinach.


The weather is still particularly cold and this is preventing the vegetables from growing.  There is no point in worrying about this because nothing can be done.


There are more strawberries ready to be picked.    You can certainly eat too many strawberries.