How farmers could benefit from fertilizer taxes

Some of the worst water quality problems result from nutrient leaching and runoff from agricultural lands.  Nitrogen and phosphorus applied to cropland and not absorbed by crops in the process of photosynthesis will, one way or another, one day or another, end up in the water.  The same goes for animal waste. The nutrients cause algae blooms, reduced concentrations of dissolved oxygen, and diminished fisheries and ecosystem health (called eutrophication). 

While there has been some effort to deal with these problems, I know of no great success stories, and water quality continues to decline in the Mississippi, the Gulf of Mexico, and the Chesapeake, the Great Lakes, and countless other water bodies.

One obvious remedy would be to tax fertilizer.  This would be a nearly Pigouvian solution.  Better would be to tax runoff and leaching directly, but that’s basically impossible for practical reasons.

The obvious but rarely stated problem is that it would probably require an extraordinarily large tax to have any real influence on the quantity of fertilizer used.  And politically powerful farmers would cry foul, which is why this kind of tax will probably never happen.

But I wonder: What would the incidence of a fertilizer tax, broadly applied, really be?  Agriculture is fairly competitive.  And demand for agricultural commodities is nearly vertical—about as inelastic as anything.  The econ 101 analysis would suggest that burden of the tax would fall mainly on consumers.  That is, food commodity prices would go up enough to compensate for most all of the tax.

Now, I’ve seen some economists propose fertilizer taxes on a graduated scale.  If fertilizer is applied at a sufficiently low rate, no tax would be levied, but the tax would then rise sharply with higher application levels (which is where most runoff and leaching comes from).  This would be a little harder to monitor, but probably not too bad.  If done this way, the total tax bill would cost farmers far less, but cause the same reduction in fertilizer use.  And farmers would still get the full compensating price increase, since less output would be collectively produced.

I think it’s possible—indeed, very probable—that the induced rise in commodity prices would more than compensate farmers for the fertilizer taxes they would have to pay under the graduated tax system.  That is, a statutory tax on farmers could cause their profits to go up.

Anyway, I don’t think anyone has made this point or emphasized it very well.  And it’s an important one, at least politically speaking, because maybe farmers could get on board with a tax that actually benefits them.  I’m not sure if it would save the Chesapeake Bay or Great Lakes from eutrophication, but I bet it would do a lot more good than anything else that’s been tried.

Update: Of course, this is no free lunch: consumers would pay in higher food prices.