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Separating Fact From Fiction

Forget Peak Oil….Try Peak N, P, and K

Below I have plotted USDA data for Nitrogen (N), Phosphorus (P), and Potasssium (K) applied to crops in the US from 1960 to the present. You will notice two distinct trends (Ex. Fertilizer labels read - for example - 10-10-10 or something like that, which corresponds to 10 Parts N, P, and K Respectively):

1. Nitrogen is and has always been the predominant fraction of fertilizers. However, more importantly N:P ratios have risen at an alarming clip from 1.06 in 1960 to 2.88 in 2007, which translates to 271% in less than 40 years. This in itself is an unsustainable trend that genetic engineering will not be able to offset. Additionally, the ratio of P to K was 134% higher in 1960 with the pivot-point (i.e., more K than P applied) being 1976-1977 (Note: I wonder if it is in any way correlated with the awesome run the Grateful Dead had during that same time frame?).

2. The percent vs. Tons P & K curves, while largely decoupled prior to to 1978 have now converged, which means that more fertilizer needs to be applied - and energy expended - to get the same Energy Return On Investment. This is quite unfortunate given the apparant lake of Global P-Pools and the recent USGS report that quantified global P at 62 Gigatons (ie 1 Billion Tons) and K at 250 Gigatons.

This data demonstrates our reliance on not just Carbon (i.e., Oil) but also N, P, and K alike. It will come to pass that the import of these 3 elements will approach if not surpass that of Oil in the next 50 years mark my words! However, there are tons of ways to ameliorate this trend and they include the application of Industrial Policy to large-scale composting ventures…Not at the Federal level but rather within counties or municipalities. These would produce two sustainable and non-trivial revenue streams via the sale of compost and anaerobic digestion of methane gas. Additionally, these materials could easily be applied to agricultural operations across the country as a dry (No Soluble P or N responsible for eutrophication), nutrient rich, carbon dense amendment. NO ZERO SUM HERE!

My primary concern going forward is what I will call the CNPS Approach, which just means that instead of having such a strong and disproportionate Carbon-Bias policy needs to focus equally on the other two-thirds of the biogeochemical pie, which are Nitrogen (N) and Phosphorus (P) (and Sulfur (S)). Everyone is familiar with the influence of CO2 and the established as well as nascent efforts aimed at monetizing carbon, but with some very simple modeling we could easily link the former to equally important Upward (i.e., CH4, N2O, and N2) and Downward Flows (i.e., NH4, NO3, PO4, and DOC) via emissions and leaching, respectively.

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Category: Agriculture, Ecological Economics, Ecological Stoichiometry, Energy

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