The Walden Effect: Farming, simple living, permaculture, and invention.

Micronutrient deficiencies in the soil end up on the plate

Map of worldwide micronutrient deficienciesUSDA data shows that the average nutritional content of grocery store vegetables has declined by 25 to 33% over the last 25 years.  Read that line again, because this is a phenomenal finding!  You need to eat a third to a quarter again as many vegetables as your grandparents did to be healthy.

Part of the reason for this decline in nutrition can be attributed to the vegetable varieties being grown today.  Solomon writes that modern plant varieties --- both hybrids and open-pollinated "heirlooms" --- are less nutritious than those developed before 1870.  His reasoning for why this decline came about seems a bit strained to me, so I'll let you check out Gardening When It Counts and read for yourself.

A more solid cause for the lack of nutrition in our vegetables is a decline of soil micronutrient levels in recent years.  The map above clearly shows that the entire continental United States suffers from a medium to widespread zinc micronutrient deficiency, and other micronutrients show a similar decline.  If the soil doesn't have a certain micronutrient in it, there's no way the vegetables grown there will supply that micronutrient to your body.

Steve Solomon's gardenSteve Solomon argues that fertilizing our gardens primarily with compost and manure from the surrounding area can accentuate these micronutrient deficiencies.  Manure quality will vary widely depending on what the animals were fed, with animals raised on substandard pasture producing micronutrient deficient manure.  Similarly, if you make compost out of your garden waste, it will be just as deficient in micronutrients as the garden soil itself.

I'll discuss Steve Solomon's solution --- fertilizing with a mixture of seedmeal, lime, guano, and kelpmeal --- next week.  But as a permaculture addict, I have to admit that I'm dubious that adding large quantities of external fertilizers is the right solution to the micronutrient problem.  We all know that dynamic accumulators can suck up micronutrients from deep in the subsoil, then make those micronutrients available to plants rooting closer to the surface.  Wouldn't it make more sense to create compost out of a diverse mixture of different dynamic accumulators, ensuring a well-balanced compost that adds organic matter to the soil as a bonus?  I'm willing to risk some failures as I build a more sustainable fertilizing regimen.

Read our microbusiness ebook about how we became financially independent on the farm.

This post is part of our Gardening When It Counts lunchtime series.  Read all of the entries:

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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.

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