Mineral Depletion in Post-Glacial Soils

THE MINERAL DEPLETION OF POST GLACIAL SOIL

Feeding the soil with minerals, to the Organic vegetable gardener, usually means putting waste organic matter, (stems, stalks & leaves which we did not eat), back into the soil. But, if the vegetable matter is grown in mineral-poor ground, what does this ultimately mean for the long term future of our soils and subsequent crops?

HOW DID MINERALS GET INTO THE SOIL?

When the last Ice Age receded, leaving behind the ground down remains of rocks, decaying animal & vegetable matter slowly combined with it over the millenia to produce humus and soil rich in minerals. We are at the end of an interglacial period and these minerals in the soil have been slowly used up, resulting in present day mineral depletion levels averaging 70% over the last 50 years alone. Delta land, fed by rivers, makes exceedingly fertile farming land because the minerals washed down from the mountains or hinterland are continuously replenishing minerals taken up by plants. Of course, meats are also affected since the animals are fed on mineral defficient crops. Ask any farmer why he feeds his animals supplements, if their grazing/silage is supposed to be satisfactory, and he will probably say 'Because the animals need it'. Farmers are not usually inclined to spend money without reason!

WARNING BELLS.

As far back as 1894 Dr. Julius Hensel wrote 'Bread from Stones', the first book on this subject. He argued that plants grown on mineralised soils were stronger and more nutritious and that the increasing power of the fertiliser industry was masking mineral deficiencies. A chiropractor, David Thomas, recently carried out a review on data published by the MRC (Medical Research Council), The Min. of Ag. & Fisheries, and by two authors of the Royal Society of Chemistry - R.A.McCance & E.M.Widdowson. The review is called 'A Study of the mineral depletion of the foods available to us a a nation over the period 1940 to 1991'. Anyone interested in further details might like to look atwww.organicgarden.org.uk/min_dep_report.pdf

The conclusions from this report make grim reading: 39% sodium, 72% copper, 59% zinc (crucial to people's behaviour & attentivness), etc. etc., all losses during the short period 1971-1991.

Should we be eating 50 pieces of fruit & veg daily, instead of the 5 as officially recommended! As this is government-produced information, why are we not being informed of the dire state of our soils? Although we appear to be eating more than enough quantities of macro-nutrients (Fats, carbohydrates & protein) no-one mentions the vital micro-nutrients (minerals & trace elements) that are vital to our physical & mental health. Please don't get me wrong; no-one with non-addictive habits in the Western world is dying from vitamin or mineral deficiency; R.D.A. levels are calculated to prevent deficiency diseases. The real questions are 'what is required for optimal health?' and 'what is optimal health?'

SOLUTIONS.

Gardener & journalist Colin Shaw, writing in The Organic Way magazine (the formerly-named Henry Doubleday Research Association, of Ryton on Dunsmore) was impressed by the quality of vegetables, grown on very thin soil over a rocky base on a wind-swept barren Scottish hillside, at The SEER Center, Pitlochrie. The soil was so poor that it had to be manufactured using municipal compost & rock dust, a quarrying by-product, 4:1 by volume. Of his visit there in late July, he comments "there were large & tasty strwaberries, the garden was in full bloom...amazing to see such a healthy, productive garden in such a hostile location". The rock dust came from basalt quarries and is a quarrying waste product known as 'quarry fines'. Analysis by the SEER Center showed around 70 minerals present and is the best rock to use, although any source of volcanic rock is acceptable.

THE PROOF OF THE PUDDING....

Colin tried this method (1 bucket rock dust to 1 barrow of compost) on his own thin-soiled, newly acquired, garden in Derbyshire, building raised beds of the mixture. To his delight, the resultant crops were strong, healthy, disease-free, with no sign of beans blackfly all the summer. He states that other research has shown that the effect builds up over the years and is looking forward to years 2 & 3 with interest. As I regularly suffer from broadbean black spot & aphid damage, I shall try this method as soon as I can!