What is soil fertility?

What does soil fertility mean? 

What are all those books talking about when they tell us some plants prefer "fertile soil"  and some plants prefer "poor soil"?  

Can we really not plant pumpkins on the same patch of ground two years in a row because "they're hungry plants"?  

What even is a "hungry plant"?

All these questions can be answered simply if we realise that these are old fashioned statements that come from a time before we knew - by looking into a microscope - what was going on in the soil.  These books are taking facts about soil from scientists in laboratories who have done very specific experiments to get a very specific answer (because to be a scientific experiment we have to know exactly what's going on and that means only having one variable at once, feeding one species of bacteria at once, testing one nutrient at once using one compound of the nutrient (usually an easy to create salt version) at once. )

That methodology doesn't take into account the enormity of what is going on due to the biological interactions in the soil.  When we take  samples, mix them up, dry it, burn it, evaporate it, make solutions out of it, electrocute it and say "This sample has virtually no nutrient content so plants will never grow there unless we add fertilizer", what have we really looked at?   Now all the biology is dead and all we really discovered is which nutrients were soluble in the sample, not the total nutrient value, because we were asking the wrong questions in the first place.

But now we know silt, sand and clay, rocks, pebbles, gravel, all those "inert" lumps of stuff your soil, is just a crystalline form of all the nutrients plants need.  ie, all basic soil types have all the nutrients within them that a plant needs to survive and thrive.

What is needed to get those nutrients out of the particles and to your plant's roots is lots of naturally occurring (in an oxygen rich environment) bacteria and fungi which can break down the crystalline structure and store the nutrients in their bodies.  These are then eaten by predators and from there and up the food chain nutrients are excreted in plant available forms, dissolved in water, so the plant can absorb them or certain bacteria and fungus can deliver them straight into the plant root.

It is that easy.

But we're all bamboozled by the stories we have been told for so long and now think that to grow vegetables we have to monitor nutrients and chemicals and fertilizers, if we don't our soil will become impoverished.  This is not the case and never was, but it is why our soils are being depleted to the point where we now have only 60 years left before all our tops soil is gone worldwide.  All these chemicals - and tilling and digging - are killing the delicate balance of the biology in the soil which does all the work naturally.  

If we put the biology back by making our own oxygen-rich compost, and stop digging, we will save our soil and our future on this planet.

Ok, I've had my rant, time for a cup of tea and to see if my compost needs turning.