FOOD FOR THOUGHT II

FOOD FOR THOUGHT (Part II) – Like sands of the hourglass, so are the days of our soils (with apologies to Socrates).  By Rob Blakemore Feb., 2017

socrates

In follow up to my highly ignored Darwin’s birthday article the other week (Ref.) and FOOD FOR THOUGHT Part I (Ref.), I would like to introduce some further Environmental Triage.

Q.- Apart from species extinctions, what is most pressing global environmental health/security issue (and most ignored)?

A. – Unglamorous topsoil loss at an irreplaceable rate of 2,000 tonnes per second.

Q. – How so?

A. – Because soil provides 99.7% of food (plus all our fibre/timber and it filters all drinking water). Soil is foundation of all primary production and thus supports biodiversity too.

Q. – Says who?

A. – Says UN’s FAOSTAT (Ref., also see Pimetel & Burgess, 2013).

Q. – Oops!  Can it be fixed?

A. – Yes, but only if we urgently redirect all our efforts & resources into education & recycling organic ‘wastes’ in order to do what Lady Eve Balfour (1947) advocated:- “Feed Earthworms”.

Despite best efforts of our humus-worm workforce, here’s some background info….

Nett topsoil loss by erosion (water, wind, tillage) is estimated by FAO (2015) at 25-40 billion tonnes per year with median 32,500,000,000 t per yr (or about -33 Gt / yr topsoil loss). A year has 31,536,000 seconds. Thus about 1,000 tonnes / sec topsoil is lost.

Surprisingly, total Global topsoil resource is unknown; an estimate is 4,000 Gt (Ref.).  If so, we have (4,000 Gt / 33 Gt/yr) = ~121 years of topsoil left.

That’s not too urgent.  But… FAO calculate just 60 years more of harvests and, as only 10% of land is arable with rates of erosion & degradation 100-1,000 times higher (FAO 2015: 103), without renewal it is possible our farms have just (121 / 10% =) 12.1 years!

And Pimental & Burgess (2013: 447) have even more worrying data estimating fertile soil lost from agricultural systems worldwide is 75 Gt / yr; more than twice the FAO rate given above, = 2,000 t tonnes / sec topsoil loss thus even 12 years may be optimistic.  This is why rivers are brown and the air dusty around farmland.

Such a timescale may seem extreme although, if my reasoning is correct, arable topsoil loss is the most urgent problem and has the most ramifications.  Now that is food-for-thought…  As a rapid solution, the broad conversion to organic farming/permaculture as a priority may yet “Feed Us All” says Worldwatch Institute (2006) whilst also, incidentally, preserving biodiversity, sequestering carbon and saving both water & fossil energy.

Indeed, as Darwin (1837, 1881: 169) told us, we need to re-appreciate the humble, heroic earthworm who he said creates ~14.09 t/acre/yr castings = 35.4 t/ha/yr x 1.5 Gha arable land = +53 Gt/yr rebuilt topsoil.  However, a major discrepancy is that FAO (2015: 103) now estimate just 0.15 t/ha/yr topsoil formation; if on 9.5 Gha of non-ice/desert land = 1.4 Gt/yr globally.  Possibly, industrial/chemical farming since the 1940s has depleted worm populations by 50-80%, or more. So the only hope for ‘Survival of the Species’ is to reverse erosion & extinction by aiming to double earthworm humus production.

The following graphic summarizes the issue.  [Note that food follows irrigation up to recent times and that excess chemical poisons are now used while earthworms decline].

2010 EW vs chems crop yield water and population with Rachel added

Unsustainable agrichemicals, food & Humanity vs. Earthwormity (as proxy for topsoil loss); just as the ‘Green Revolution’ depleted topsoil, a ‘Brown Revolution’ is needed to recreate it.

Conserving earthworms (vermicomposters & field worms) is the best & only way to rebuild topsoil/humus as is simply & graphically demonstrated in the following photo.

Untitled-1

Here’s the article’s earlier pdf version if you need hard copy – FOOD-FOR-THOUGHT-II.

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