While scrolling through news accounts of the recent boom in the agrochemicals industry — yes, that’s how I spend my days — I came across an interesting take on biofuels and phosphate, a key element of soil fertility.

The article, from Investors Business Daily, takes a standard rah-rah position on what it deems a “heyday in the heartland.” The journal wants to make sure its readers know there’s plenty of cash to be made investing in the companies catering to the great boom in industrial agriculture.

With corn and soy prices both at or near record highs, the article tries to handicap which crop farmers will plant more of in the coming growing season. Impossible to tell, it concludes. Nevertheless:

Fertilizer producers benefit either way. Corn demands more fertilizer than soy or wheat. But price competition among the grains, stoked largely by federal supports for ethanol production, has bled generously into fertilizer markets.

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That’s boilerplate. Anyone who’s checked out the stock chart of Mosaic — the fertilizer giant, two-thirds owned by agribiz behemoth Cargill, recently profiled here — knows that the fertilizer industry has been essentially printing money.

But the Investors Business Daily article really started to pique my interest when it turned to phosphorus — the “P” of NPK (nitrogen, phosphorus, potassium), the main macronutrients required for plant growth.

Of course, industrial agriculture makes a fetish of NPK. Like a ’70s-era faddist who thinks you can maintain health while eating whatever junk food you want, so long as you take a vitamin pill containing “100 percent RDA” of every vitamin, industrial agriculture enthusiasts insist that by isolating NPK and dumping it into soil, you’ve solved the problem of soil fertility.

NPK mentality neglects micronutrients and forgets that healthy soil relies on teeming populations of microorganisms, whose function we don’t fully understand. Lashing the soil with industrial fertilizer doesn’t renew life in the soil; it squeezes life out. Someday, I predict, NPK dogma will crumble and seem as absurd as relying on a bowl of Total for nourishment.

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For now, though, we live in an NPK world — and biofuel production relies absolutely on mined and synthesized macronutrients.

OK, back to the Investors Business Daily article and phosphorus. Toward the bottom, we find this:

Phosphates shot to $300 and then to $400 a ton last year, and are now on track to break $800 … Out of 50 billion tons of potential phosphate rock reserves worldwide, the USGS estimates the U.S. holds only 3.4 billion tons. Morocco owns 21 billion, China has 13 billion. All are keen to closely manage the resource.

Wow, so our big “renewable,” domestic energy source relies heavily on a mined substance, of which we own a tiny reserve. The biggest store lies in an Islamic nation, representing a religious group our government has antagonized. The second-biggest store is lodged within the borders of a budding geopolitical rival. Hmm.

Then we get this:

Global consumption of phosphate rock is projected to grow 2.3% a year. But that rate of growth could increase due to demand for biomass used in biofuel production.

Farmers are harvesting larger shares of the plant rubble left after harvest — a natural source of potassium and phosphate when turned back into the soil. The loss of that natural fertilizer means more P & K demand.

What the article is saying is this: If we transition to cellulosic ethanol — which utilizes whole plants, not just the seeds, as in conventional ethanol — we’ll need even more phosphorus. And demand for this finite resource, located mainly in geopolitically troublesome places, will grower at an even faster clip than the current 2.3 percent compounded annual rate.

I should note here that phosphate mining, as I laid out in the above-linked post on Mosaic, is environmentally ruinous. It leaves behind radioactive waste.

Note further that cellulosic ethanol — perpetually five years away from commercial viability — counts in some quarters as biofuel’s great green hope.

To me, all of this exposes the folly of relying on industrial agriculture to create a “clean” fuel source for transportation. To avoid the political and ecological troubles of mining, we need to nudge agriculture back toward the nutrient loop — recycling animal and vegetable waste back into the soil and building true and sustainable soil fertility. I believe we can “feed the world” that way; we surely can’t feed the world (or its cars) for long using an agriculture style that relies on finite mined products.

As for biofuels, I don’t see how they fit in to a return to sustainable agriculture. Sustainably fertilized land can feed our bellies, but not our cars, too. We surely can’t squeeze enough excess grain out of sustainably managed land to make a dent in the fuel demands of a country with a 210 million-plus auto fleet.

Rather than promote biofuels, environmentalists should be pushing for alternatives to the internal-combustion engine — and for a return to sustainable agriculture.

Here’s a talking point. The Global Subsidies Initiative reckons that the U.S. government supports biofuels to the tune of about $13 billion per year between now and 2012. Amtrak gets about $1.2 billion per year. Let’s defund biofuels and invest the proceeds in a functional national rail system. No?